VR6 VAG-COM codes. Engine cutting out at lights.

[aclwalker 3]

Hi all. I've just VAG-COMed my own 1994 VR6 as it's been conking out at traffic lights a lot recently and hunting on idle when cold and wandering a bit when hot.

 

I get the following codes:

 

00537 - Lambda (Oxygen Sensor) Regulation

11-10 - Control Limit Not Reached - Intermittent

 

00543 - Maximum Engine Speed Exceeded -- Engine Warranty VOID! ;-)

35-10 - - - Intermittent

 

00533 - Idle Speed Regulation

10-10 - Adaptation Limit Not Reached - Intermittent

 

I'm guessing the Lambda sensor is the obvious culprit (very high mileage car and probably not replaced for ages (if at all)). The hunting on cold start is making me think twice though. I had a very quick look at the lambda values while idling (engine not quite fully hot, but not cold either) and it seemed to range from just under 0.8 to over 1.2, fluctuating quite a lot. I believe this is quite a big fluctuation, but what is acceptable?

 

I'm assuming the idle speed regulation is a symptom of the general problem rather than the cause.

 

But what about the maximum engine speed sensor code? The text is as is on VAG-COM, smiley and all. I don't red line the car. Have I got a faulty crank speed sensor (camshaft sensor replaced not too long ago)? Or has it really been hammered at my MoT a wee while back?

 

Any help greatly appreciated.

 

Also, a reminder for those in the Glasgow area that I am willing to scan cars (as long as you have the new-style connector).

[dr_mat 0]

Sounds like it's gonna be one of the holy triumvirate: the MAF, the lambda, or the ISV at fault..

You might also have a crank sensor problem, but that's very hard to diagnose. (The fault gets overwritten as soon as the engine stops.)

[Supercharged 2]

00543 - Maximum Engine Speed Exceeded -- Engine Warranty VOID! ;-)

 

Naughty!

 

Could also be a Vac leak - check the flexi pipe to the tb

[Kevin Bacon 5]

I'm guessing the Lambda sensor is the obvious culprit (very high mileage car and probably not replaced for ages (if at all)). The hunting on cold start is making me think twice though. I had a very quick look at the lambda values while idling (engine not quite fully hot, but not cold either) and it seemed to range from just under 0.8 to over 1.2, fluctuating quite a lot. I believe this is quite a big fluctuation, but what is acceptable?

 

Not always, sometimes a more fundamental issue causes the 02 adaptation to run out of of options.....dead MAF for instance, or air leaks as mentioned above.

 

O2 should fluctuate between 0.1 to 0.8V at idle when hot and stick on 0.45V during the warm up cycle. Unlikely your sensor will exceed 1V.

 

But what about the maximum engine speed sensor code? The text is as is on VAG-COM, smiley and all.

 

The engine has been over revved by someone / persons unknown, plain and simple. Or has it been chipped? Remappers always raise the rev limit, or remove it completely.

[aclwalker 3]

Sounds like it's gonna be one of the holy triumvirate: the MAF, the lambda, or the ISV at fault..

You might also have a crank sensor problem, but that's very hard to diagnose. (The fault gets overwritten as soon as the engine stops.)

 

dr_mat, would a crank sensor problem not also make the car hard to restart for a while? I have no problems starting it again on conking out. I remember the hall sensor on my old Golf failing and it would fail completely and the engine would die and refuse to start for a while.

 

Is the crank sensor not of the same principle as the hall sensor? (I understand that the hall sensor in the VR6 is ignored by the ECU if it fails, but the engine still runs. I guess the crank sensor can't be ignored in the same way.)

 

I reckon the lambda is probably the problem. It could even just be waterlogged as I was forced through a large puddle recently due to the months of rain we've had in Glasgow. ;) I've ordered a new one anyway.

[aclwalker 3]

00543 - Maximum Engine Speed Exceeded -- Engine Warranty VOID! ;-)

 

Naughty!

 

Could also be a Vac leak - check the flexi pipe to the tb

 

Thanks, I'll check that.

[aclwalker 3]

Not always, sometimes a more fundamental issue causes the 02 adaptation to run out of of options.....dead MAF for instance, or air leaks as mentioned above.

 

O2 should fluctuate between 0.1 to 0.8V at idle when hot and stick on 0.45V during the warm up cycle. Unlikely your sensor will exceed 1V.

 

Hi Kev,

 

I don't think the measurements I was making with VAG-COM were Volts. I think it's the actual 'lambda' value. I followed this http://www.the-corrado.net/wiki/index.php/VR6_ECU_Reset_Procedure

 

I also read somewhere else about lambda and VAG-COM and it said that a lambda of 1.00 is perfect 14.7 air to fuel ratio. More than 1 was lean (IIRC) while less than was rich (again IIRC). Sorry, I can't remember where I read this.

 

I'll see if VAG-COM gives me the voltage too though...

 

The engine has been over revved by someone / persons unknown, plain and simple. Or has it been chipped? Remappers always raise the rev limit, or remove it completely.

It hasn't been chipped. It's a very standard car, almost totally repaired and maintained by me, but I can't do my own MoT. :cry:

 

The guy who does the MoT is very good, fair, and doesn't fail on the usual MoTer unprovable trivia. But one of his boys might have rallied it when taking it to park up the street (he has limited space). I might mention it to him next year if I remember, but I can't prove anything.

 

Nobody else drives it either...

[dr_mat 0]

dr_mat, would a crank sensor problem not also make the car hard to restart for a while? I have no problems starting it again on conking out. I remember the hall sensor on my old Golf failing and it would fail completely and the engine would die and refuse to start for a while.

 

Yes I think so. They tend to lose definition as they get hot, so the engine stops, and won't restart for a while till it cools a little.

 

But could just be a loose connection causing it to momentarily loose signal, couldn't it?

 

....

 

Btw overrevved probably means someone did something stupid like dropping it into 2nd at 90. You can't force the engine to overrev just with your right foot cos the ECU limiter kills the power, you have to force it to overrev through the gearbox ..

[RS VR6 0]

Off the Ross Tech site:

 

"00533 - Idle Speed Regulation: Adaptation Limit (Add) Exceeded

Possible Symptoms

Bad Fuel Economy

Possible Causes

Air Leak between Mass Air Flow (MAF) Sensor and Engine

Injector(s) faulty

Fuel Pressure Regulator faulty

Throttle Body faulty

Intake Air Filter dirty

 

Possible Solutions

Perform Throttle Body Adaptation

Check Hoses and Pipes to/between Components

Check Intake Air Filter

Check Fuel Pressure Regulator

Check Exhaust Gas Recirculation (EGR) Valve

Check Injector(s)

 

 

00537 - Lambda (Oxygen Sensor) Regulation: Upper Limit

 

Possible Symptoms

No Lambda control

Engine running problems

Possible Causes

Short to Ground

Injector defective (blocked)

Fuel pressure regulator defective

Fuel pump defective

Fuel tank empty

 

Possible Solutions

 

Check Lambda probe and Lambda control

 

Check injectors (N30...N33)

 

Check fuel pressure regulator

 

Check fuel pump

 

Check fuel level in fuel tank

 

 

 

00537 - Lambda (Oxygen Sensor) Regulation: Lower Limit

Possible Causes

 

Activated charcoal filter solenoid valve 1 (N80) leaking/sticking

 

Injector defective (not closing completely)

 

Fuel pressure regulator defective

 

Possible Solutions

 

Check charcoal filter solenoid valve 1 (N80)

 

Check injectors (N30...N33)

 

Check fuel pressure regulator"

 

 

Its tottaly possible that they are "false" codes caused by another issue.

 

I had the 00537 for the longest time. I eventually checked the wiring to the lambda plug. Turns out that one of the wires was down to one strand. I replaced the entire plug, cleared the ECU and the problem went away.

[G60Jet 1]

00543 - Maximum Engine Speed Exceeded -- Engine Warranty VOID! ;-)

 

Naughty!

 

Could also be a Vac leak - check the flexi pipe to the tb

 

also means its been above the red line for a few seconds to trip that

[aclwalker 3]

Well, drove the car today to the dealer today and it was a good bit better. It still conked out a couple of times, but maybe it's just the weather we've been having recently and the flood I had to drive through. Maybe the lambda's drying out. I ordered a new one anyway...

[RS VR6 0]

Normally a bad lambda won't cause the car to stall out...it will cause the car to run super rich.

 

The stalling is probably caused by something else. Did you clean your idle stabilizer? Its posible that its dirty and not opening all the way at idle.