ECU Explanation needed.

[Big_kev]

Hi folks

Recently had a couple of problems with the S2 3b. My alternator failed to charge the battery the other day and as a result the car stopped. Pulled out a few bird feathers and hit (tapped) alternator with a hammer and started working again. Next day had a fuel line rupture spewing precious go go juice onto the road (now sorted). Today i leant a bit heavy on the loud peddle and the car has gone onto what sounds and feels like 4 cylinders.

I have extraced the fault codes from the ecu and this is how they read.

Control Module Part Number: 895 907 404 BA
Component and/or Version: MOTOR PMC 1
Software Coding: 0261200484
Work Shop Code: 1267356560
5 Faults Found:
00537 - Lambda (Oxygen Sensor) Regulation
08-10 - Control Limit Surpassed - Intermittent
65535 - Shareware Version. To Decode all DTCs
00-00 - Please Register/Activate
00532 - Shareware Version. To Decode all DTCs
07-00 - Please Register/Activate
00525 - Oxygen Sensor (G39)
03-10 - No Signal - Intermittent
00513 - Shareware Version. To Decode all DTCs
03-00 - Please Register/Activate

I have had a look at as many as the codes as possible and although i can read them they don't make much sense to me as i do not know the location of some of the parts.

This is what i have so far

00535
Description
Lambda sensor control
- Maximum control limit exceeded
- Minimum control limit exceeded

[B]Possible fault Description
Low fuel pressure (<3.3 bar)
Intake air leak after G70
Leak in exhaust prior to catalyst
G39 faulty
Fuel pressure too high (> 4 bar)

65535
cannot locate


00532
Description
Supply Voltage, B+
- Signal too high
- Signal too low

Possible Fault Description
Supply voltage (B+) into J220 exceeds 16 volts
Faulty alternator
Poor ground at J220
Flat battery

00525
Description

Lambda Sensor, G39
- Signal to B+
- Signal to ground
- No change in signal

Possible Fault Description
Open circuit to J220
Lambda sensor heater (Z19) faulty
Fuse for Z19 blown
G39 faulty
Signal wire short to ground or shielding
Ignition system failure
Intake leak after mass air flow sensor (G70)
Leak in exhaust system before catalysts
Ground wire between pin 10 on J220 and engine block open circuit

00513
Description

Engine Speed Sensor, G28
- No change in signal
- Mechanical fault

Possible Fault Description



I can understand tha 00537 may have been caused by the fuel leak, 00532 by the failed alternator and subsequent flat battery, but with regards to the last couple i have the explanation but cannot determine or know what to look for regarding the codes like g39, j220 etc. Is there any documentaion that indicates these sensors etc. I have the familly album but cannot locate what i am looking for.

Any assistance would be greatly appreciated as car currently close to knackers yard.

Kevin

[S2central.net]

Rather than go into detail on all of these - I suspect some are result of alternator misbehaviour and may not be that meaningful in terms of root cause analysis.

Clear all these codes with VAGCOM, then go for a drive to see which faults come back as currently active.

FYI - J220 is the schematic label for the ECU and G39 is the lambda probe. Don't worry about G28 (speed sensor) as you always get that one with car not running.

Was the car running OK before you had alternator problems, or did you just pull codes cause of the misfire ?

Paul

[Big_kev]

HI

I have cleared the codes from the ecu and rechecked and come up with this one.

VAG-COM Version: Release 409.1-S

Control Module Part Number: 895 907 404 BA
Component and/or Version: MOTOR PMC 1
Software Coding: 0261200484
Work Shop Code: 1267356560
1 Fault Found:
65535 - Internal Control Module Memory Error
00-00 - -

All the codes were taken while the engine was running is this correct?

I have taken off the spark leads from pots 1 & 2 (this was from the front of the engine) and the engine continued to run but no better or worse.

What should i do next.

Much appreciated

Kevin

[S2central.net]

Right well - that code is either a bad earth at the ECU, or a faulty ECU, or a bad chip checksum if its been got at by a lazy / uneducated tuner.

Check all fuses and earth points. Theres an earth strap on the bulkhead near the ECU and another at the drivers side... Theres also two big earth points on the inlet manifold.

If earths are all good then I can checkout your ECU for bad chips if you like... Just cover the postage to and fro.

Paul

[Big_kev]

More than happy to for you to check out chips for me. Be happy to pay for postage and any inconvenience to you. If you could pm me your address i shall get this organised immediately.

I will of course check all the earths that i can find but would be obliged if you could check the chips out as a matter or course. I am not confident in the london based mob that carried out the upgrade in the first place.

[Big_kev]

Hi Guys

Still looking for some assistance in diagnosing this. Have cleared all codes and only memory error returns. The car is still going like a pig (very lumpy). Could the timing belt have jumped a tooth or something and if so how would i check.

Thanks in advance

PS if anyone is wanting a small holiday to the west coast of scotland (isle of bute) you might just happen to see me their.

Kevin

[S2central.net]

Check that the timing marks align on camshaft and crankshaft correctly. Have you checked cylinder compression yet. Are all the sparkplugs tight - the HT leads in good condition - is the dissy aligned with timing marks.

I'll send you a PM later with my address if you want the ECU checked over.

Paul

[Big_kev]

Cheers Paul ECU would be most appreciated.

Going to sound stupid but what am i looking for to check for timing marks and what would i need to buy to check cylinder compression.

HT lead was arcing but that is resolved. All plugs are getting a spark when tested with spare plug against the engine. Don't know how to check to see if plug is sparking in the bore as it needed to be grounded on engine to spark.

[Big_kev]

Done a bit more checking and found that the spark plugs do not spark across the gap when out of the bore. Used a spare one in the bore to keep the compression and inserted new plugs in the HT lead. The only occassion when it would spark at all was when earthed off of the engine. Is the right or indicitive of an earth problem somewhere else. I was under the impression it should spark across the gap even out of the engine.

[Big_kev]

guys

Still looking for some help on this one. Have just replaced the timing belt and checked the alingment etc and this still hasn't sorted the problem. Car still very lumpy when idling and when revved. Cannot drive the car in this state.

Could anyone offer some further suggestions that i may try.

Many thanks in advance

Kevin

[dubmeister]

The plug will only fire when earthed to the engine/ block etc- did you get a nice shock??
If you carry out all the checks mentioned before, timing marks, dizzy aligned etc
Was the car running fine until the alternator problem?
If it is missing/running on 4 you can check which cylinder by pulling a lead off one at a time -no difference in revs- that is the problem cylinder.
Check all the electrical connectors on the engine to be connected properly and go from there.

[UrS4boy]

guys

Still looking for some help on this one. Have just replaced the timing belt and checked the alingment etc and this still hasn't sorted the problem. Car still very lumpy when idling and when revved. Cannot drive the car in this state.

Could anyone offer some further suggestions that i may try.

Many thanks in advance

Kevin

By chance is the throttle body position switch connector disconnected? That produces the lumpy revving symptoms you have. (But it could be something else).

[Acidburn]

wasn't the belts out slightly iirc in one of your other posts? might have got it mixed up but I did post up pictures to someone who needed to time it up again.

[newsh]

You may well just have a big boost leak, that'll make it run real lumpy. Can you do a pressure test on the inlet tract?

"Intake leak after mass air flow sensor (G70)"

[Big_kev]

Cheers for the responses guys.

I have changed the timing belt and re-aligned the engine as the belt needed changing anyway. Have set car up to all the timing marks.

Have checked plugs, leads etc and all seems OK.

I cannot determine whether the car runs worse or not when taking off the leads one by one as the engine runs so lumpy in the first instance

As for the throttle body position switch connector, could someone give me a clue to where that would be.

@dubmeister Been there with the shock before so used insulated pliers. Not much hair left to straighten but there was no need for me to try