VCDS errors - help needed

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vanilla_ice

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Hi,

I have a 2001 S3 AMK and at the weekend I was trying to fix some leaks with the PCV pipes under the inlet manifold. Yesterday, I tightened up various jubilee clips and then degreased (and rinsed the pipework with water) so I could then spot if any of leaks return.

Car started as normal this morning but it was soon obvious there was a problem. Intermittent boost/dumping of boost and lurching, shortly followed by the EPC and ESP dash lights coming on. I suspected the MAF so unplugged it, but noticed no difference. Got to my destination and retrieved the following results from a scan:

6 Faults Found:
16712 - Knock Sensor 1 (G61): Signal too High
P0328 - 35-10 - - - Intermittent
16705 - Engine Speed Sensor (G28): Implausible Signal
P0321 - 35-10 - - - Intermittent
16395 - Bank 1: Camshaft A (Intake): ****** Setpoint not Reached (Over-Advanced)
P0011 - 35-10 - - - Intermittent
16706 - Engine Speed Sensor (G28): No Signal
P0322 - 35-10 - - - Intermittent
16622 - Manifold Pressure / Boost Sensor (G31): Signal too High
P0238 - 35-10 - - - Intermittent
16486 - Mass Air Flow Sensor (G70): Signal too Low
P0102 - 35-00 - -

I cleared these down and then went for a short journey with MAF reconnected. No improvement. Another scan produced this:

3 Faults Found:

16486 - Mass Air Flow Sensor (G70): Signal too Low
P0102 - 35-10 - - - Intermittent
16705 - Engine Speed Sensor (G28): Implausible Signal
P0321 - 35-10 - - - Intermittent
16395 - Bank 1: Camshaft A (Intake): ****** Setpoint not Reached (Over-Advanced)
P0011 - 35-10 - - - Intermittent

From a quick search on here I gather 16486 probably needs a new MAF to resolve that particular fault (can this be confirmed please? Is it worth cleaning with contact cleaner?), but what about 16705 and 16395?

I have found the following Ross-Tech pages:

http://wiki.ross-tech.com/wiki/index.php/16705/P0321/000801
http://wiki.ross-tech.com/wiki/index.php/16395/P0011/000017

Is there any way of checking engine speed sensor without removing it?
I am not aware of ever having timing issues.

Having searched various threads on here and can confirm the following:

Oil pickup was replaced less than a year ago. Oil has been changed since and oil level is fine. In-tank fuel pump replaced ‘the cheaper way’ about 18 months ago.

I’m hoping the VVT unit isn’t goosed. I can check the resistance with a multi-meter (Am I aiming for 10-15ohms?).

Any other suggestions as in what to try next would be gratefully received.

Many thanks.
 
My guess would be a faulty crankshaft speed sensor which is confusing the MAF and camshaft position sensors causing timing/fuelling issues.
 
Thanks Retroman. Anyway of confirming this?

I don't know if this is of any consequence but the engine appears to idle as normal.
 
1) Very unlikely that you would have 4 sensors failing simultaneously

2) A faulty MAF sensor could cause running problems, stalling, poor starting or fuel economy issues but it would not trigger faults with the “timing sensors” e.g., camshaft position and crank speed sensors. If faulty, you would expect the car to run slightly better with it disconnected

3) Your camshaft position sensor is over advancing the timing. A symptom of over advanced timing is “pre-ignition” which is spotted and corrected (if possible) by a knock sensor (in your first list).

4) Why is your camshaft position sensor over advancing the timing? I suspect because it is struggling to synchronise engine speed with ignition timing for fuelling purposes. The timing of the ignition is altered with engine speed.

5) The MAF looks “confused” and gone into fixed, default factory setting as it is the same plugged-in or unplugged.

6) The one unique and unambiguous sensor signal is the one in the first list for the crankshaft speed sensor saying “no signal”.

Like “wheel speed/ABS sensors” you could remove the crankshaft speed sensor, give it a clean and see if the situation improves. Was it dislodged or contaminated during your recent work?
 
Many thanks for your response.

I don't believe it was moved, but I have wondered if water has gone somewhere it shouldn't have. I was going to check/dry/clean the sensor connector etc.

I see some drop the oil and remove filter for better access when removing the sensor. Would I loose oil through sensor's hole if I didn't drop the oil first?

What should I clean with?

If a replacement was required would a sensor from ECP be suitable?

Finally, should I drive the car as it is?

Thanks again.
 
vanilla_ice said:
Thanks Bill.

ECP jobber OK?
Click to expand...

Genuine Bosch one from GSF or a dealer (try the ASN parts request)... do not use pattern parts...

ECP supplied ones (for whatever reason) seemed to have a habit of failing... not used them myself for ages on MAF's as I couldn't trust them..

<tuffty/>
 
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I don’t know your engine (BMW engines are my speciality) but this sensor is normally up by the bell housing. Your oil is in the sump so no oil will gush out when you remove it. They normally look like a little plastic barrel – there is a magnet inside – debris on the outside can cause issues. Clean it with some clean tissue and a solvent such as meths or brake cleaner – Halfords sell a gentle electrical cleaner solvent. Did you dislodge the electrical connection? – It may just have water inside. Some BMW connectors have a rubber washer inside that keeps the tension when the connector is snapped together – sometimes they fall out during maintenance.

Buying unbranded, non-OE sensors can be a risk as quality control seems not as good. I’ve been Ok with aftermarket ABS and brake pad wear sensors but for important engine management sensors I would stick with OE or the company that makes the OE sensor.

Personally, I would avoid driving the car as serious mis-timing issues and pre-ignition is not good for the engine.
 
Thanks all.

Plan is to check electrical connector and clean/dry as necessary. If the faults persist I'll go with a Bosch sensor from GSF.

Am I asking for trouble if I nursed it home (5 miles)?

Finally, is there a common ground that could affecting the various sensors in the faults above?
 
So I checked the connections for the crank sensor. Pin 1 was slightly corroded (connector socket and sensor plug). There were also cracks around pin 1 on the sensors plug，so proceeded with replacing the sensor.

I managed to replace from below without removing the oil filter， but it would certainly be quicker/easier with it out of the way.

Cleared all fault codes down and they haven't returned. Normal power delivery restored.

Thanks all.
 
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So you problem was caused by washing the engine and water getting into the sensor due to cracks in the connector cover?
 
Well done matey – nice feeling to sort out a problem like this by your own efforts. A good example of how one fault can lead to several others and how diagnostics need to be used in conjunction with some normal human brain power and common sense. :glee:
 
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Stuart B said:
So you problem was caused by washing the engine and water getting into the sensor due to cracks in the connector cover?
Click to expand...

Possibly，but I'm not convinced.

The cracks were only visible on the inside of the sensors plug near pin 1.

I don't think it was water related as the way the loom connector points down and goes over the sensor`s plug， water would need to have risen inside the connector to cause the problem. Plus， it was more of a light rinse than a wash and focused to the right of dipstick. Connector is to the left as you look at the engine.

I think it may have just been a coincidence and down to age.

Retroman said:
Well done matey – nice feeling to sort out a problem like this by your own efforts. A good example of how one fault can lead to several others and how diagnostics need to be used in conjunction with some normal human brain power and common sense. :glee:
Click to expand...

Yep. Satisfying to fix it without another garage bill!
 
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