ECU Fault Codes
DISCLAIMER: The information in these documents are a collection from experience (friends or myself), magazine articles, mailing lists and Internet web sites etc. So don't take these as 100% correct gospel, hence I don't take any responsibility for any of these guides.
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Created: 19 Dec 2001
Updated: 5 Aug 2002
Revision 6

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Figure 1
10-pin ALDL Test Plug connections.

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Figure 2
Location of the 10-pin ALDL plug in a Nova engine bay.

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Figure 3
Close up of the 10-pin ALDL plug in a Nova engine bay.

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Figure 4
ECU warning lamp on the dash board.

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Figure 5
Location of 10-pin ALDL Test Plug in a Calibra.

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Figure 6
Location of 10-pin ALDL Test Plug in an Astra-F.

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Figure 7
16-pin ALDL Test Plug connections.

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Figure 8
Location of 16-pin ALDL Test Plug in Astra MK4 within Fuse Box.

What are 'fault codes'?

Fault codes are recognised problems or faulty sensors to the EMU (Engine Management Unit) which is a ECU (Electronic Control Unit). The ECU relies on the sensors on your car to make it run at it's optimum performance at all times. When a sensors goes wrong or there is a fault with the engine, the ECU sees this problem and logs the fault code within it's memory (NOTE: not ALL problems are logged, depends on what system your car has). Often the ECU warning light on the dash board may light up, indicating to you that there is a problem.

NOTE: The ECU warning lamp usually needs to be on for more than 30 seconds before the ECU logs a fault code. Otherwise it could consider it an intermittent fault and ignore it.

Do all ECU's handle fault codes?

If your engine is fuel injected then it needs a ECU to control the injection timing. All Vauxhall models that have injection need a ECU to do this and hence they will have the facility to log fault codes. If your engine is run on a carburetor, then it has no ECU, hence no fault codes can be logged or read.

How do I read the fault codes?

There are two common ways to do this. The first is to use a TECH1 or a TECH2 reader which is an expensive bit of equipment. Some dealerships could charge you £50 just to connect it up to your car. The second option is FREE and YOU can do it....with a paper clip.

The paper clip method flashes the ECU warning lamp on the dash, and you read the amount of flashes and pauses. The chart supplied in this article tells you what the fault code means. The paper clip is used to short out two pins in the ALDL connector (also know as 'diagnostics plug' or 'test connector'). These are commonly coloured blue and can be located in the car or within the cabin, depending on model of car and fueling system.

It doesn't matter if the engine is running or not when the flash codes are being read out. In fact it is beneficial to have the engine running since on some ECU's, if it doesn't see the engine running, it will produce a fault code straight away and gives a misleading fault code.

Please note on newer ECU cars in the region of 2000 onwards, most now use ECU codes which can not be read out via the paper clip method. You will have to consult a ECU/fault code specialist or your nearest Vauxhall/Opel Dealer.

What pins do I short out?

If you have Motronic or GM-Multec fuel system, then you'll find a 10-pin ALDL connector. To read the flash codes, then short pins A and B (see figure 1).

If its a Simtec 56.0 or 56.1 fuel system (i.e. Ecotec engine) then you'll find a 10-pin ALDL connector. To read the flash codes you need to short pins A and B (see figure 1).

If its a Simtec 56.5 fuel system (i.e. Ecotec engine) then you'll find a 16-pin ALDL connector. To read the flash codes (P codes) you need to short out pins 5 and 6 (see figure 6).

Can I damage anything if I short the wrong pins?

Yes it is possible but unlikely, depending on what pin you short out. Most of them are 0v connections, but there are live +12v supply pins on there as well depending on which ALDL plug you have. If you are in doubt, don't do it! Double check the diagrams shown.

Where do I find the ALDL connector on the car?

Again if you have a Motronic or GM-Multec system, then these are commonly found in the engine bay or within the fuse box. Look for a 10-pin connector which is usually plugged into a blanking socket (i.e. not actually connected to anything). See figures 2, 3 and 5.

However if you have a Simtec 56.0 or 56.1 system, then the 10-pin ALDL connector can also be found in the engine bay or within the fuse box. See figures 2, 3 and 5.

However if you have a Simtec 56.5 system, then the 16-pin ALDL connector can be found in the fuse box area or under the trim to the hand brake or under the bulge in the carpet beside the passenger front seat. See figures 7 and 8.


  General Notes: To the top

Just before you start, make sure you note the following:

  • If you don't have one, buy a Haynes manual for your car and have this is front of you if you find a fault and wish to investigate it.
  • You'll need a paper clip and a pencil and paper to jot down the fault codes as they are flashed up.
  • You do not need to start the engine but it doesn't hurt. Just switching on the electric's is enough (i.e. dash lights come on).
  • If the paper clip is inserted in the wrong 2 pins, it is unlikely to damage anything, but double check you have the correct connections in the first place.
  • For the ECU to log a fault, the ECU warning lamp on the dash usually has to be on for more than 30 seconds.

OK, got all the above? Then follow the steps below (remember to click on the pics for a bigger view):


Step 1 Step 2 Step 3
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Locate the ALDL plug within your car. In this case it the 10-pin type can be found in the engine bay. With the connector pointing towards you and the retaining clip at the bottom, short the top two pins (A & B) on the left-hand side with the paper clip. Get in the car and switch on the engine. The ECU light will begin to flash and pause a number of times. Take a note of the flash patterns.

  How to read Motronic or GM-Multec Flash Codes: To the top

The Motronic or GM-Multec fuel systems use a 2 digit flash code. The engine does not have to be running when reading the codes, although it doesn't hurt if it is.

Once the wire link is in place and the electric's are on, the ECU warning lamp will begin to flash out the codes (wait for the initial boot up check that lights up all the warning lamps). Each fault code is repeated 3 times and then it moves onto the next one (if any). Once at the end of the logged fault code list, it will go to the beginning again, giving you plenty of time to note down the code (on each fault code shown, there will be a pause before it shows the next one). It will carry on like this forever until you remove the key from the ignition or the battery runs flat. To clear the fault codes, simply remove the battery leads for a few minutes and then reconnect.

For example, lets say there was a ECU warning lamp noted and the owner wanted to read what fault code was logged. The owner has already put the wire link in place and switched on the ignition. A flash is indicated by an astrix (*) and a pause is shown as a dash (-).

*-** (1 flash, 1 pause and another 2 flashes = code 12)
*-** (12)
*-** (12)

**-*** (23)
**-*** (23)
**-*** (23)

*-** (12)
*-** (12)
*-** (12)

**-*** (23)
**-*** (23)
**-*** (23)

*-** (12)
*-** (12)
*-** (12)

Owner then takes the key out of the ignition.

Lets go through what has happened. After switching on the ignition, the dash board lights up showing the self check, after that all the lights go out and the ECU warning light begins to flash the error code. The first code is 12 (one flash, a pause and then two flashes). This is repeated 3 times.

Code 12 at this moment means initiation of diagnosis. After that came code 23, which means 'Knock control module', i.e. there is most likely a faulty unit or a bad connection at its plug. After code 23 has been repeated 3 times it flashes a separator code, which is code 12.

It flashes this 3 times before going to the next fault code. The next code is code 23 again which means its finished showing the logged fault codes and has started back at the beginning. The owner can switch off the ignition. A healthy car should display a stream of code 12's. To find out what fuel system you have, read the "Fault Code Chart" below.


  How to read Simtec 56.0/56.1 Flash Codes: To the top

The Simtec 56.0/56.1 fuel systems use a 2 digit flash code. The engine ideally needs to be running when reading the fault codes, otherwise it may show incorrect fault codes.

Once the wire link is in place and the engine is running, the ECU warning lamp will begin to flash out the codes (wait for the initial boot up check that lights up all the warning lamps). Each fault code is repeated 3 times and then it moves onto the next one (if any). Once at the end of the logged fault code list, it will go to the beginning again, giving you plenty of time to note down the code (on each fault code shown, there will be a pause before it shows the next one). It will carry on like this for ever until you remove the key from the ignition or the battery runs flat. To clear the codes simply turn on and off the ignition 30 times with a 5 second 'on' gap in-between (time allowed for self check to finish).

For example, lets say there was a ECU warning lamp noted and the owner wanted to read what fault code was logged. The owner has already put the wire link in place and switched on the ignition. A flash is indicated by an astrix (*) and a pause is shown as a dash (-).

*-** (1 flash, 1 pause and another 2 flashes = code 12)
*-** (12)
*-** (12)

**-*** (23)
**-*** (23)
**-*** (23)

*-** (12)
*-** (12)
*-** (12)

**-*** (23)
**-*** (23)
**-*** (23)

*-** (12)
*-** (12)
*-** (12)

Owner then takes the key out of the ignition.

Lets go through what has happened. After switching on the ignition, the dash board lights up showing the self check, after that all the lights go out and the ECU warning light begins to flash the error code. The first code is 12 (one flash, a pause and then two flashes). This is repeated 3 times.

Code 12 at this moment means initiation of diagnosis. After that came code 23, which means 'Knock control module', i.e. there is most likely a faulty unit or a bad connection at its plug. After code 23 has been repeated 3 times it flashes a separator code, which is code 12.

It flashes this 3 times before going to the next fault code. The next code is code 23 again which means its finished showing the logged fault codes and has started back at the beginning. The owner can switch off the ignition. A healthy car should display a stream of code 12's (note: some ECU systems will also show code 31 or 19 because it doesn't see the engine turning over, this is not a fault because you haven't started the car). Simply start the car and read the fault codes again. To find out what fuel system you have, read the "Fault Code Chart" below.


  How to read Simtec 56.5 Flash Codes (P Codes): To the top

The Simtec 56.5 fuel systems use a 4 digit flash code. The engine ideally needs to be running when reading the fault codes, otherwise it may show incorrect fault codes.

Once the wire link is in place and the engine is running, the ECU warning lamp will begin to flash out the codes (wait for the initial boot up check that lights up all the warning lamps). Each fault code is repeated 3 times and then it moves onto the next one (if any). Once at the end of the logged fault code list, it will go to the beginning again, giving you plenty of time to note down the code (on each fault code shown, there will be a pause before it shows the next one). It will carry on like this for ever until you remove the key from the ignition or the battery runs flat. To clear the codes simply turn on and off the ignition 30 times with a 5 second 'on' gap in-between (time allowed for self check to finish).

For example, lets say there was a ECU warning lamp noted and the owner wanted to read what fault code was logged. The owner has already put the wire link in place and switched on the ignition. A flash is indicated by an astrix (*) and a pause is shown as a dash (-).

Note that 10 flashes = number 0.

**********-*-*-***** (10 flashs, 1 pause, 1 flash, 1 pause , 1 flash, 1 pause and 5 flashes = P code 0115)
**********-*-*-***** (0115)
**********-*-*-***** (0115)

**********-***-***-********** (0330)
**********-***-***-********** (0330)
**********-***-***-********** (0330)

**********-*-*-***** (0115)
**********-*-*-***** (0115)
**********-*-*-***** (0115)

**********-***-***-********** (0330)
**********-***-***-********** (0330)
**********-***-***-********** (0330)

Owner then takes the key out of the ignition.

Lets go through what has happened. After switching on the ignition, the dash board lights up showing the self check, after that all the lights go out and the ECU warning light begins to flash the error code. There is no initiation flash code, the ECU will flash out the fault codes straight away. This is repeated 3 times.

P code 0115 means 'Intake manifold pressure sensor', i.e. there is most likely a faulty unit or a bad connection at its plug. It flashes this 3 times before going to the next fault code. Remember to show a 0 number it flashes the ECU warning lamp 10 times.

The next code is code 0330 which means 'Knock sensor 2' which suggests the engine has two knock sensors on it, hence the 2nd one is faulty or has bad connections. Again this flashes the same fault P code 3 times before moving onto the next. In this case it there are no more faults and the P codes repeat themselves.

The owner can switch off the ignition. A healthy car should display no fault codes what so ever, i.e. the ECU warning lamp never comes on or flashes. Some ECU systems will also show code 0335 because it doesn't see the engine turning over, this is not a fault because you haven't started the car. Simply start the engine and read the fault codes again. If 0335 shows again while the engine is on, then its a fault. To find out what fuel system you have, read the "Fault Code Chart" below.


  Fault Code Chart: To the top

Over the years there have been many different models in the Vauxhall range and hence there are different ECU systems. With each different system there are (usually) different fault codes. Listed below are the fault codes, search for the model of your car and click on the link to view the fault codes.

This list is by no means complete and still need gaps filling in and some corrections. If you know more about other engine systems or can correct anything below, please e-mail us at ecu_codes@topbuzz.co.uk. Thank you.


 Vauxhall Astra / Opel Kadett: To the top
Model Engine Code Year System
Astra-F 1.4i X14NZ 1997 GM-Multec CFi
Astra-F 1.4i X14XE 1996-1997 GM-Multec CFi
Astra-F 1.4i cat C14NZ 1990-1996 GM-Multec CFi
Astra-F 1.6 cat C16NZ 1990-1995 GM-Multec CFi
Astra-F 1.8i cat C18NZ 1991-1994 GM-Multec CFi
Astra Van 1.6i cat C16NZ 1991-1994 GM-Multec CFi
Astra-F 1.4i cat C14SE 1991-1996 GM-Multec MPi
Astra-F 1.6i cat C16SE 1992-1995 GM-Multec MPi
Astra-F 1.4i cat C14SE 1993-1994 GM-Multec MPi
Astra-F 1.6i X16SZ 1993-1996 GM-Multec CFi
Astra-F 1.6i cat C16SE 1993-1994 GM-Multec MPi
Astra-F 1.6i X16SZR 1996-1997 GM-Multec CFi
Astra 1.6i cat C16SE 1991-1992 Bosch Motronic 1.5
Astra 1.8i 18SE 1987-1991 Bosch L3 and EZ61
Astra GTE 2.0 20NE 1987-1990 Bosch Motronic ML4.1
Astra GTE 2.0 20SEH 1987-1990 Bosch Motronic ML4.1
Astra 2.0i 20SEH 1990-1993 Bosch Motronic 1.5
Astra 2.0i cat C20NE 1991-1995 Bosch Motronic 1.5
Astra 2.0i 16v DOHC 20XEJ 1988-1991 Bosch Motronic 2.5
Astra-F 2.0i 16v DOHC C20XE 1993-1996 Bosch Motronic 2.5
Astra-F 2.0i cat SOHC C20NE 1991-1995 Bosch Motronic 1.5.2
Astra-F 1.8i 16v C18XE/L 1993-1997 Siemens Simtec 56.0/56.1
Astra-F 1.8i 16v X18XE 1996-1998 Siemens Simtec 56.5
Astra-F 2.0i 16v X20XE 1995-1998 Siemens Simtec 56.5

 Belmont: To the top
Model Engine Code Year System
Belmont 1.4i cat C14NZ 1990-1993 GM-Multec CFi
Belmont 1.6i C16NZ 1987-1993 GM-Multec CFi
Belmont 1.8i cat C18NZ 1990-1992 GM-Multec CFi

 Brava: To the top
Model Engine Code Year System
Brava 2.3i cat 4ZD1 1995-1996 GM-Multec MPi

 Calibra: To the top
Model Engine Code Year System
Calibra 2.0i SOHC & 4x4 cat C20NE 1990-1996 Bosch Motronic 1.5.4
Calibra 2.0i 16v DOHC cat C20XE 1990-1993 Bosch Motronic 2.5
Calibra 2.0i 16v & 4x4 DOHC cat C20XE 1993-1996 Bosch Motronic 2.8
Calibra 2.0i 16v Turbo 4x4 DOHC cat C20LET 1992-1996 Bosch Motronic 2.7
Calibra 2.5i 24v V6 cat C25XE 1993-1996 Bosch Motronic 2.8
Calibra 2.5i 24v V6 cat X25XE 1997-1997 Bosch Motronic 2.8
Calibra 2.0i 16v cat X20XEV 1994-1998 Siemens Simtec 56.0/56.1

 Carlton: To the top
Model Engine Code Year System
Carlton 2.0i 8v 20SE 1987-1990 Bosch Motronic ML4.1
Carlton 2.0i 8v SOHC C20NE 1986-1987 Bosch Motronic ML4.1
Carlton 2.0i 8v SOHC C20SE 1987-1990 Bosch Motronic ML4.1
Carlton 2.0i 8v SOHC C20NE 1990-1994 Bosch Motronic 1.5
Carlton 2.0i 8v SOHC C20SE 1990-1994 Bosch Motronic 1.5
Carlton 2.0i cat SOHC C20NEJ 1990-1993 Bosch Motronic 1.5
Carlton 2.4i cat CIH C24NE 1988-1990 Bosch Motronic 1.3
Carlton 2.4i cat CIH C24NE 1990-1993 Bosch Motronic 1.5
Carlton 2.6i cat CIH C26NE 1990-1994 Bosch Motronic 1.5
Carlton 3.0i 12v cat CIH C30NE 1990-1994 Bosch Motronic 1.5
Carlton 3.0i 24v cat DOHC C30SE 1989-1994 Bosch Motronic 1.5
Carlton 3.0i 24v cat Estate DOHC C30SEJ 1990-1994 Bosch Motronic 1.5

 Campo: To the top
Model Engine Code Year System
Campo 2.3 cat 4ZD1 195-1996 GM-Multec MPi

 Vauxhall Cavalier / Opel Vectra-A: To the top
Model Engine Code Year System
Cavalier/Vectra-A 1.6i cat C16NZ 1990-1993 GM-Multec CFi
Cavalier/Vectra-A 1.6i cat C16NZ2 1993-1994 GM-Multec CFi
Cavalier/Vectra-A 1.6i C16NZ/NZ2 1993-1996 GM-Multec CFi
Cavalier/Vectra-A 1.6i X16SZ 1993-1995 GM-Multec CFi
Cavalier/Vectra-A 1.8i cat C18NZ 1990-1994 GM-Multec CFi
Cavalier/Vectra-A 2.0i 20SEH 1987-1990 Bosch Motronic ML4.1
Cavalier/Vectra-A SRi 130 20SEH 1987-1988 Bosch Motronic ML4.1
Cavalier/Vectra-A 2.0i cat C20NE 1991-1992 Bosch Motronic 1.5
Cavalier/Vectra-A 2.0 SOHC 20NE 1990-1993 Bosch Motronic 1.5
Cavalier/Vectra-A 2.0i & 4x4 SOHC 20SEH 1990-1993 Bosch Motronic 1.5
Cavalier/Vectra-A 2.0i SOHC cat C20NE 1990-1993 Bosch Motronic 1.5
Cavalier/Vectra-A GSi 2000 16v DOHC 20XEJ 1989-1991 Bosch Motronic 2.5
Cavalier/Vectra-A 2.0i 16v 4x4 DOHC cat C20XE 1989-1992 Bosch Motronic 2.5
Cavalier/Vectra-A 2.0i 16v 4x4 Turbo C20LET 1993-1995 Bosch Motronic 2.7
Cavalier/Vectra-A 2.0 20NE 1987-1990 Bosch Motronic ML4.1
Cavalier/Vectra-A 2.0i SOHC 20NE 1990-1993 Bosch Motronic 1.5
Cavalier/Vectra-A 2.0i cat SOHC C20NE 1990-1993 Bosch Motronic 1.5
Cavalier/Vectra-A 2.0i 16v C20XE 1989-1995 Bosch Motronic 2.5
Cavalier/Vectra-A 2.0i 16v X20XEV 1993-1995 Siemens Simtec 56.0/56.1

 Vauxhall Corsa MK1 / Opel Corsa-B: To the top
Model Engine Code Year System
Corsa-B & Combo 1.2i C12NZ 1992-1993 GM-Multec CFi
Corsa-B & Combo 1.2i X12SZ 1993-1997 GM-Multec CFi
Corsa-B & Combo 1.4i X14SZ 1996-1997 GM-Multec CFi
Corsa-B 1.4i & Van C14NZ 1993-1996 GM-Multec CFi
Corsa-B 1.4i C14SE 1992-1994 GM-Multec MPi
Corsa-B 1.4i X14XE 1994-1996 GM-Multec S
Corsa-B 1.6i C16NZ 1990-1991 GM-Multec MPi
Corsa-B 1.6i 16v GSi C16SE 1994-???? GM-Multec MPi
Corsa-B 1.6i 16v GSi C16XE 1993-1994 GM-Multec S
Corsa-B 1.6i 16v automatic X16SZ 1993-???? GM-Multec MPi

 Frontera: To the top
Model Engine Code Year System
Frontera 2.0i cat SOHC C20NE 1991-1995 Bosch Motronic 1.5
Frontera 2.4i cat CIH C24NE 1991-1995 Bosch Motronic 1.5
Frontera 2.0i X20XE 1995-1996 Bosch Motronic 1.5
Frontera 2.0i 8v X20SE 1995-1997 Bosch Motronic 1.5.4
Frontera 2.2i 16v X22XE 1995-1996 Bosch Motronic 1.5.4

 Vauxhall Nova / Opel Corsa-A: To the top
Model Engine Code Year System
Nova/Corsa-A 1.2i 8v cat X12SZ 1993-1996 GM-Multec CFi
Nova/Corsa-A 1.2i 8v cat C12NZ 1990-1994 GM-Multec CFi
Nova/Corsa-A 1.4i 8v cat C14NZ 1990-1993 GM-Multec CFi
Nova/Corsa-A 1.6i 8v GTE cat C16NZ 1990-1992 GM-Multec CFi
Nova/Corsa-A 1.4i 8v cat C14SE 1992-1994 GM-Multec MPi
Nova/Corsa-A 1.6i 8v cat C16SE 1992-1993 GM-Multec MPi
Nova/Corsa-A 1.6i 8v GSi cat C16SE 1993-1994 GM-Multec MPi
Nova/Corsa-A 1.6i 8v MPi cat C16SEI 1990-1992 Bosch Motronic 1.5

 Omega: To the top
Model Engine Code Year System
Omega 2.0i 20SE 1987-1990 Bosch Motronic ML4.1
Omega 2.0i SOHC 20SE 1990-1993 Bosch Motronic 1.5
Omega 2.0i SOHC cat C20NE 1990-1993 Bosch Motronic 1.5
Omega 2.0i SOHC cat C20NEJ 1990-1993 Bosch Motronic 1.5
Omega-B 2.0i 8v X20SE 1994-1997 Bosch Motronic 1.5.4
Omega 2.4i CIH cat C24NE 1990-1993 Bosch Motronic 1.5
Omega 2.5i X25XE 1994-1996 Bosch Motronic 2.8
Omega-B 2.5i 24v X25XE 1994-1997 Bosch Motronic 2.8.1
Omega 2.6i CIH cat C26NE 1990-1993 Bosch Motronic 1.5
Omega 3.0i X30XE 1994-1996 Bosch Motronic 2.8.1
Omega 3.0i CIH cat C30NE 1990-1994 Bosch Motronic 1.5
Omega 24v DOHC cat C30SE 1989-1994 Bosch Motronic 1.5
Omega 24v DOHC Estate cat C30SEJ 1990-1994 Bosch Motronic 1.5
Omega-B 2.0i 16V X20XEV 1994-1999 Siemens Simtec 56.0/56.1

 Senator: To the top
Model Engine Code Year System
Senator 2.6i CIH cat C26NE 1990-1993 Bosch Motronic 1.5
Senator 3.0i C30LE 19??-19?? Bosch Motronic 1.5
Senator 3.0i CIH cat C30NE 1990-1994 Bosch Motronic 1.5
Senator 3.0i 24v DOHC cat C30SE 1989-1994 Bosch Motronic 1.5
Senator 3.0i 24v Estate DOHC cat C30SEJ 1990-1992 Bosch Motronic 1.5

 Sintra: To the top
Model Engine Code Year System
Sintra 2.2i X22XE 1996-1999 Bosch Motronic 1.5.4
Sintra 3.0i 24v V6 X30XE 1996-1999 Bosch Motronic 2.8.3

 Tigra: To the top
Model Engine Code Year System
Tigra 1.4i 16v X14XE 1994-1996 GM-Multec MPi
Tigra 1.6i 16v X16XE 1994-1997 GM-Multec MPi

 Vauxhall Vectra MK1 / Opel Vectra-B onwards: To the top
Model Engine Code Year System
Vectra-B 1.6i 16v X16SEJ 1996-1999 GM-Multec CFi
Vectra-B 1.6i 16v X16XEL 1996-1999 GM-Multec CFi
Vectra-B 1.6i 16v X16SZR 1995-1999 GM-Multec CFi
Vectra-B 1.8i 16v X18XE 1995-1999 Siemens Simtec 56.5
Vectra-B 2.0i 16v X20XE 1995-1999 Siemens Simtec 56.5
Vectra-B 2.5i V6 24v X25XE 1995-1999 Bosch Motronic 2.8.3

BOSCH Motronic ECU Fault Codes
This fault code chart shows the Bosch Motronic fault codes for the following systsms:- 1.5, 1.7, 1.8, 2.5, 2.7, 2.8, 2.8.1, 2.8.3, 3.1, MP3.1, 3.2, 4.1, 5.1, 5.1.1, First Generation and MPi.

  Bosch Motronic Code Chart: To the top
Code: Item:

Fault:

12 Initiation of diagnosis. n/a
13 Oxygen sensor No change in voltage/open circuit.
14 Coolant Temperature Sensor (CTS) Low voltage
15 Coolant Temperature Sensor (CTS) High voltage
16 Knock sensor 1 No change in voltage
17 Knock sensor 2 No change in voltage
18 Knock control unit No signal, Engine Control Unit (ECU) fault
19 RPM signal (crankshaft sensor) Incorrect signal
21 Throttle position sensor High voltage
22 Throttle position sensor Low voltage
23 Knock sensor module n/a
24 Vehicle speed sensor (VSS) No signal
25 Injector valve 1 High voltage
26 Injector valve 2 High voltage
27 Injector valve 3 High voltage
28 Injector valve 4 High voltage
28 Fuel pump relay Low voltage
29 Injector valve 5 High voltage
31 Engine RPM signal (crankshaft sensor) No signal
32 Injector valve 6 High voltage
32 Fuel pump relay High voltage
33 Inlet manifold pressure sensor Voltage too high
34 Exhaust Gas Re-circulation (EGR) valve Voltage too high
34 Manifold Absolute Pressure (MAP) sensor Low voltage
35 Idle Speed Control Valve (ISCV) Poor or no idle speed control
36 Incorrect RON/Octane setting Damaged RON plug or bad connection.
37 Engine self-diagnosis (fault code light) Low voltage
38 Oxygen sensor Voltage low (1990 model year on)
39 Oxygen sensor Voltage high (1990 model year on)
41 Vehicle speed sensor (VSS) Low voltage
41 1 gear ident switch (C20LET systems) Low voltage
41 EST Line coil cylinder 2&3 (M2.8/XEV systems) High voltage
42 Vehicle speed sensor (VSS) High voltage
42 1 gear ident switch (C20LET systems) High voltage
42 EST Line coil cylinder 2&3 (M2.8 / XEV systems) High voltage
43 Linear EGR system (XEV systems) Faulty
44 Oxygen sensor Air/fuel mixture too lean (weak)
45 Oxygen sensor Air/fuel mixture too rich
46 Air pump relay High voltage
47 Air pump relay Low voltage
47 Linear EGR Position (XEV systems) Faulty
48 Battery voltage Low voltage
49 Battery voltage High voltage
51 ECU Programmable memory PROM error, hardware failure
52 Engine check light; final stage (fault code light) High voltage
53 Fuel pump relay Low voltage
54 Fuel pump relay High voltage
55 Engine Control Unit (ECU) fault Renew Engine Control Unit (ECU)
56 Idle Speed Control Valve (ISCV) Short to earth
57 Idle Speed Control Valve (ISCV) Interruption
59 Inlet manifold valve 1 Low voltage
61 Fuel Tank Vent Valve (FTVV) Low voltage
62 Fuel Tank Vent Valve (FTVV) High voltage
63 Inlet manifold valve 1 High voltage
63 EST Line coil cylinder 2&3 (M2.8 / XEV systems) Low voltage
64 EST Line coil cylinder 1&4 (M2.8 / XEV systems) Low voltage
65 Carbon Monoxide (CO) potentiometer Low voltage
66 Carbon Monoxide (CO) potentiometer High voltage
67 Throttle valve switch - idle position switch Low voltage - switch not opening
68 Throttle Switch (TS) - idle contact Idle switch not opening
69 Air Temperature Sensor (ATS) Low voltage
71 Air Temperature Sensor (ATS) High voltage
72 Throttle Switch (TS) - full load contact High voltage - Full load switch not running
73 Air Flow Sensor (AFS) Low voltage
74 Air Flow Sensor (AFS) High voltage
75 Transmission switch - torque control Low voltage
76 Automatic Transmission (AT) torque control Engaged long, ignition retard long
79 Traction control unit Incorrect ignition/injector cut-off
81 Injector valve 1 Low voltage
82 Injector valve 2 Low voltage
83 Injector valve 3 Low voltage
84 Injector valve 4 Low voltage
85 Injector valve 5 Low voltage
86 Injector valve 6 Low voltage
87 Air Conditioning (AC) cut off relay Low voltage
88 Air Conditioning (AC) cut off relay High voltage
89 Oxygen sensor heater Low voltage
91 Oxygen sensor heater High voltage
92 Camshaft sensor failure (XEV systems) Faulty
93 Hall Effect Switch (HES) Low voltage
94 Hall Effect Switch (HES) High voltage
95 Hot start valve Low voltage
96 Hot start valve High voltage
97 Traction control unit - ignition/injection cut off Incorrect signal - high voltage
98 Oxygen sensor Open circuit, wiring break
99 Code unknown n/a
113 Turbo boost control Boost presure high, out of range
114 Idle boost valve Above upper limit
115 Full boost pressure Below lower limit
116 Boost pressure Above upper limit
117 Wastegate valve Low voltage
118 Wastegate valve High voltage
121 Oxygen sensor 2 Lean exhaust, weak mixture
122 Oxygen sensor 2 Rich mixture/exhaust
123 Inlet manifold valve 1 Blocked
124 Inlet manifold valve 2 Blocked
132 Exhaust Gas Re-circulation (EGR) valve Incorrect signal
133 Exhaust Gas Re-circulation (EGR) valve 2 High voltage
134 Exhaust Gas Re-circulation (EGR) valve 2 Low voltage
135 'Check engine' lamp (fault code lamp) Low voltage
136 Engine Control Unit (ECU) n/a
137 Engine Control Unit (ECU) box High temperature
141 Secondary air pump Not enough air
142 Secondary air pump Air without pump
143 Immobiliser function in ECU No or incorrect signal
144 No immobiliser signal recived Faulty unit or break in wiring
145 Incorrect immobiliser signal received Faulty unit or break in wiring

GM-Multec ECU Fault Codes
This fault code chart shows the GM-Multec fault codes for the following systems:- SPi, MPi, CFi, M and S.

  GM-Multec Code Chart: To the top
Code: Item:

Fault:

12 Initiation of diagnosis. n/a
13 Oxygen sensor No change in voltage/open circuit.
14 Coolant Temperature Sensor (CTS) Low voltage
15 Coolant Temperature Sensor (CTS) High voltage
16 Knock signal circuit n/a
18 Knock control processor n/a
19 Crank Angle Sensor (CAS) Incorrect RPM signal
21 Throttle Potentiometer Sensor (TPS) High voltage
22 Throttle Potentiometer Sensor (TPS) Low voltage
24 Vehicle Speed Sensor (VSS) No speed signal or low voltage
25 Injector valve Low voltage
28 Fuel pump relay contacts Contact problem
29 Fuel pump relay Low voltage
32 Fuel pump relay High voltage
33 Manifold Absolute Pressure (MAP) sensor High voltage
34 Manifold Absolute Pressure (MAP) sensor Low voltage
35 Idle stepper motor Poor or no idle speed control
41 Amplifier control signal, cylinders 2 and 3 (Direct Ignition System (DIS)) High voltage
42 Amplifier control signal, cylinders 1 and 4 (Direct Ignition System (DIS)) High voltage
43 Primary ignition (distributor systems) High voltage
44 Oxygen sensor Air/Fuel mixture too lean (weak)
45 Oxygen sensor Air/Fuel mixture too rich
46 Amplifier (Direct Ignition System (DIS)) control signal (A+B) High voltage
47 Linear exhaust gas re-circulation (EGR) position n/a
49 Battery supply to Engine Control Unit (ECU) High voltage (greater than 17 volts)
51 Engine Control Unit (ECU) Defective ECU (disconnect and reconnect (ECU), then recheck for fault codes). Memory failure
52 Secondary air pump relay Low voltage
53 Secondary air pump relay High voltage
54 Idle Carbon Monoxide (CO) potentiometer n/a
55 Engine Control Unit (ECU) fault Renew Engine Control Unit (ECU)
56 Air control soleniod Low voltage
57 Air control soleniod High voltage
61 Fuel tank vent valve (FTVV) Low voltage
62 Fuel tank vent valve (FTVV) High voltage
63 Amplifier control signal, cylinders 2 and 3 (Direct Ignition System (DIS)) Low voltage
64 Amplifier control signal, cylinders 1 and 4 (Direct Ignition System (DIS)) Low voltage
65 Primary ignition (distributor systems) Low voltage
66 Throttle position sensor (TPS) Hose broken
67 Air Flow Sensor (AFS), hot wire meter (air mass meter) Signal is outside normal operation parameters (out of range)
68 Air Flow Sensor (AFS), hot wire meter (air mass meter) Faulty air mass meter signal, incorrect frequency
69 Air Temperature Sensor (ATS) (MPi only) Low voltage
71 Air Temperature Sensor (ATS) (MPi only) High voltage
72 Amplifier (Direct Ignition System (DIS)) control signal (A+B) Lead interruption, open circuit
75 Torque control (Automatic Transmission (AT) only) Low voltage
76 Torque control (Automatic Transmission (AT) only) Continuous
81 Injector valve High voltage
83 Immobiliser No or wrong code
84 Immobiliser No signal
85 Immobiliser Wrong signal
87 Air conditioning cut-off relay Low voltage
88 Air conditioning cut-off relay High voltage
92 Camshaft sensor Faulty hall effect sensor or circuit
93 Quad drive module (in ECU) n/a

Siemens Simtec 56.0/56.1 ECU Fault Codes

  Siemens Simtec 56.0/56.1 Code Chart: To the top
Code: Item:

Fault:

12 Initiation of diagnosis. n/a
13 Oxygen sensor Open circuit
14 Coolant temperature sensor Voltage low
15 Coolant temperature sensor Voltage high
16 Knock sensor signal circuit No change in voltage
19 Incorrect Revs per Minute (RPM) signal (crankshaft sensor) Incorrect signal, check sensor
21 Throttle position sensor (TPS) Voltage high
22 Throttle position sensor (TPS) Voltage low
23 Knock control module signal Out of range
24 Vehicle speed signal (VSS) No signal
25 Injector valve 1 Voltage high
26 Injector valve 2 Voltage high
27 Injector valve 3 Voltage high
28 Injector valve 4 Voltage high
37 Check light (fault code lamp) Voltage low
38 Oxygen sensor circuit Voltage high
39 Oxygen sensor circuit Voltage low
44 Oxygen sensor Lean exhaust (weak mixture)
45 Oxygen sensor Rich exhaust (rich mixture)
48 Battery Voltage low
49 Battery Voltage high
52 Check light (fault code lamp) Voltage high
53 Fuel pump relay Voltage low
54 Fuel pump relay Voltage high
55 Engine Control Unit (ECU) faulty Check chassis earth and ECU connector.
56 Idle air control Voltage high
57 Idle air control Voltage low
61 Fuel tank vent valve Voltage low
62 Fuel tank vent valve Voltage high
69 Intake air temperature sensor Voltage low
71 Intake air temperature sensor Voltage high
73 Mass air flow temperature Voltage low
74 Mass air flow temperature Voltage high
75 Torque control (automatic) Voltage low
76 Torque control (automatic) Continuous signal, ignition retard long
81 Injector valve 1 Voltage low. Injector short circuit to ground.
82 Injector valve 2 Voltage low. Injector short circuit to ground.
83 Injector valve 3 Voltage low. Injector short circuit to ground.
84 Injector valve 4 Voltage low. Injector short circuit to ground.
87 Air Conditioning (A/C) cut-off relay Voltage low
88 Air Conditioning (A/C) cut-off relay Voltage high
91 Oxygen sensor heater Voltage high
92 Camshaft sensor Incorrect signal
98 Oxygen sensor heater Voltage low, open circuit

Siemens Simtec 56.5 ECU Fault Codes

  Siemens Simtec 56.5 Code Chart (P Codes): To the top
Code: Item: Fault:
0100 Mass Air Flow (MAF) sensor n/a
0105 Intake manifold pressure sensor n/a
0110 Intake Air Temperature Sesnor (ATS) n/a
0115 Intake Coolant Temperature Sesnor (CTS) n/a
0120 Throttle Potentiometer Sensor (TPS) n/a
0130 Heated Exhaust Gas Oxygen (HEGO) sensor n/a
0135 Heated Exhaust Gas Oxygen (HEGO) sensor heater n/a
0150 Heated Exhaust Gas Oxygen (HEGO) sensor n/a
0173 Heated Exhaust Gas Oxygen (HEGO) sensor n/a
0201 Injector valve 1 n/a
0202 Injector valve 2 n/a
0203 Injector valve 3 n/a
0204 Injector valve 4 n/a
0205 Injector valve 5 n/a
0206 Injector valve 6 n/a
0230 Fuel pump n/a
0325 Knock sensor n/a
0330 Knock sensor 2 n/a
0335 Crank sensor n/a
0340 Camshaft sensor n/a
0351 Ignition coil 1 and 4 n/a
0352 Ignition coil 2 and 3 n/a
0400 Exhaust gas circulation valve n/a
0403 Exhaust Gas Re-circulation (EGR) valve n/a
0410 Secondary air pump relay n/a
0412 Secondary solenoid valve n/a
0433 Tank vent valve n/a
0500 Idle speed stepper motor/idle air regulator n/a
0560 Battery n/a
1110 Switch over valve solenoid n/a
1112 Switch over valve 1 n/a
1113 Switch over valve 2 n/a
1120 Throttle body malfunction n/a
1229 Power supply relay n/a
1231 Fuel pump relay n/a
1320 Knock control cylinder 1 n/a
1327 Knock control cylinder 2 n/a
1328 Knock control cylinder 3 n/a
1329 Knock control cylinder 4 n/a
1405 Exhaust Gas Re-circulation (EGR) valve n/a
1410 Secondary air pump relay n/a
1411 Secondary air pump n/a
1501 Immobiliser control unit n/a
1502 Immobiliser control unit n/a
1503 Immobiliser control unit n/a
1530 Air flow relay n/a
1600 Internal control module n/a
1601 Engine Control Unit (ECU) too hot n/a
1602 Knock control module n/a
1604 Knock control unit n/a
1605 Knock control unit n/a
1606 Knock control unit n/a
1640 Knock control unit or quad drive module n/a
1690 MIL/Engine fail (malfunction indicator lamp) n/a
1740 Torque control unit n/a

Special thanks go to CavWeb, Andy Kirwan , Marko Virtanen and list members on the 'vauxhall_senator' mailing list for the help and advice on the construction of this fault code chart and engine systems.


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