Camshaft POS - Error P0391 -Resolved.

[irelandbuyer]

I’ve been meaning to write up my experience with the P0391 error – Camshaft Position Sensor.

The issue arose when I started the car and it was initially rough but cleared when car warmed up. The day after the Emissions Light came on the dash. I brought it into my shop and they hooked it up and showed the P0391 error. They cleared it but it arose again. I brought it back and they hooked it up again to the VAG.

We paid particular attention to Block 93 and the readings were:

Group 093: Continuous Camshaft Adjustment (Phase Position)
4.5°KW Phasenlage Intake Bank 1
8.6°KW Phasenlage Intake Bank 2
8.6°KW Phase Position Exhaust Bank 1
5.3°KW Phase Position Exhaust Bank 2

From what I gathered online, that the timing chain service limit 8 and these values would be greatly in excess of that indicated a potentially serious problem.

It was clear that reading the forums here and elsewhere that it was pointing to a timing problem.

I took it to the main dealer for an initial diagnostic (I wanted a second opinion). The write up from their works was as follows:

“Carried out investigation into EMA and lack of power. Confirmed EML On. Road-tested but unable to experience lack of power. Carried out a diagnostic check. Numerous voltage faults logged in various control unit. 3 faults logged in engine ECU. “Camshaft Position Sensor “B” Circuit – Range performance. Issue is with Sensor for Camshaft Position G301 (Sensor 4) (Left Bank Outer). Gained Access to Sensor. Disconnected. Found sensor heavily contaminated with oil and oil ingress into wiring. Connected tool and checked supply voltage and Earth Pin 1+3. All Ok. Checked signal on sensor (Hall Effect). All OK. Recommend replacing sensor and connector and 3 wires followed by extended road-test.. Removed and replaced Cam Sensor G3011 + Connector + Wiring. Started vehicle and tested. Engine is running rough. Checked fault memory. Fault is still present. Checked MVB for Cam Shaft Adjusters + Misfire recognition for both Bank 1+2. An adjustment is being recorded of 0.75’ on Bank 2 Exhaust Cam Shaft. Recommend to check cam/valve timing. R+R airbox and inlet pipe. R+R engine bay and front Tube. R+R both cylinder head covers. Checked valve timing using specialist tools. All OK. Reassembled removed parts. Checked MVB again. Adjustment for exhaust Cam Bank 2 is still recorded. Checked signal for adjuster from Engine ECU and compared to Bank 1. Same signal is recorded. Checked signal for both Hall Sensors on Bank 2. Both signals are correct. Swopped inlet and exhaust cam adjusters and carried out basic settings. Fault now logged with inlet adjusters. Swopped back again and re-did basic settings. Fault back on exhaust adjuster. Recommend a new exhaust cam adjuster on Bank 2. Removed and replaced adjuster and carried out basic settings. System Test Now OK. Carried out a Road-test. All OK.”

I was originally thinking this was going to be a very expensive engine out timing chain replacement and thankfully it was a lot less than that.

What was interesting to me was that two independents couldn’t get to the bottom of the problem and it took a main dealer to undertake more in-depth fault analysis to get a result….was costly but not as dear as a timing chain fix....

[Joe2.0E]

Good Result, Which Dealer was it ?