Help advice needed VW Golf limp mode problems
Discussion
On February 2019 I bought my Volkswagen golf GTD (registered on 01/09/2019) from a Ford dealer group. 26 days from purchase, I experienced a fault - the glow plug light flashed, and the car went into limp mode, so lose power. After a while I realised this was a temperamental fault, that happened occasionally. Initially, it kept saying I loss tyre pressure, but the tyres appeared okay having checked and reset values. The tyre pressure loss does not appear with faults now, but did at start, thought worth mentioning just in case linked.
I rang the dealership and emailed highlighting the fault – I was aware under the Consumer Rights Act that I had a statutory right to reject a new or used car within 30days of purchase if any fault is found. After a lot of headache and persuasion the dealership arranged for the car to go to Volkswagen dealership and for the fault to be fixed, at the dealership’s expense.
1. Ford Dealership arranged for the car to be taken to a VW dealer, for them to diagnose the fault and fix. I was told that the VW dealer looked at my car and updated the software. I then collected 2nd April 2019. I believe (was told) they reprogrammed both main and spare key.
2. On the morning of 5th April 2019, the same fault came up on the dash and loss of power. The Ford dealership told me to contact the VW garage myself and arrange for this to be fixed. I took to the VW garage and they replaced the vacuum hose. The invoice states “Turbo Fault Stor Found Low Vacuum Pressure on Cold Start. Replaced Vacuum Hose & Non Return Valve. Retested and All OK” – parts 124855/hoses, 124855/gaskets, 124855/screws, coolant, distilled water included as parts that were changed.
3. For information ahead of VW looking at the car I took the car to a local Seat garage who ran a diagnostics on the car VCDS, Windows based VAG/VAS Emulator and 2 faults were found:
a. 7934 – Turbocharger Boost Control Position Sensor Circuit
P2563 00 [096] – Implausible Signal
Intermittent – Not Confirmed – Tested Since Memory Clear
b. 9127 – Actuator Module for Turbocharger 1
P00AF 00 [096] – Stuck
Intermittent – Not Confirmed – Tested Since Memory Clear
4. Unfortunately, the fault re-appeared in November 2019. I decided to see what the problem was independently (did not contact Ford dealer), as I already had a service booked in with a local garage that I used previously, they specialise in BMWs and Mercedes. The garage said the fault code seems to suggest fuel pressure related issues (EGR seemed fine), they fitted a genuine fuel filter and told me to put miles on, it could be due to fuel starvation.
5. On 19th May 2020, the horrible flashing glow plug light came up and went into limp mode - so the fault still lingers. Once the fault is triggered it will not go off (or out of limp mode) until the engine switched off, whenever I have restarted the engine afterwards it has worked fine (no fault).
In the winter months the car was quite poor at starting, always did start, but sputters and struggles more than I would expect for a car of this age.
Does anyone have any idea what the cause of this fault could be, or experienced before? Recommendations what they would do?
If I were to go back to the Ford dealership and ask for them to help, from my past experiences I would expect this to be extremely difficult and they would be reluctant to help. Do they have to help legally, as it appears to be the same fault that I notified within 30 days of purchase?
I rang the dealership and emailed highlighting the fault – I was aware under the Consumer Rights Act that I had a statutory right to reject a new or used car within 30days of purchase if any fault is found. After a lot of headache and persuasion the dealership arranged for the car to go to Volkswagen dealership and for the fault to be fixed, at the dealership’s expense.
1. Ford Dealership arranged for the car to be taken to a VW dealer, for them to diagnose the fault and fix. I was told that the VW dealer looked at my car and updated the software. I then collected 2nd April 2019. I believe (was told) they reprogrammed both main and spare key.
2. On the morning of 5th April 2019, the same fault came up on the dash and loss of power. The Ford dealership told me to contact the VW garage myself and arrange for this to be fixed. I took to the VW garage and they replaced the vacuum hose. The invoice states “Turbo Fault Stor Found Low Vacuum Pressure on Cold Start. Replaced Vacuum Hose & Non Return Valve. Retested and All OK” – parts 124855/hoses, 124855/gaskets, 124855/screws, coolant, distilled water included as parts that were changed.
3. For information ahead of VW looking at the car I took the car to a local Seat garage who ran a diagnostics on the car VCDS, Windows based VAG/VAS Emulator and 2 faults were found:
a. 7934 – Turbocharger Boost Control Position Sensor Circuit
P2563 00 [096] – Implausible Signal
Intermittent – Not Confirmed – Tested Since Memory Clear
b. 9127 – Actuator Module for Turbocharger 1
P00AF 00 [096] – Stuck
Intermittent – Not Confirmed – Tested Since Memory Clear
4. Unfortunately, the fault re-appeared in November 2019. I decided to see what the problem was independently (did not contact Ford dealer), as I already had a service booked in with a local garage that I used previously, they specialise in BMWs and Mercedes. The garage said the fault code seems to suggest fuel pressure related issues (EGR seemed fine), they fitted a genuine fuel filter and told me to put miles on, it could be due to fuel starvation.
5. On 19th May 2020, the horrible flashing glow plug light came up and went into limp mode - so the fault still lingers. Once the fault is triggered it will not go off (or out of limp mode) until the engine switched off, whenever I have restarted the engine afterwards it has worked fine (no fault).
In the winter months the car was quite poor at starting, always did start, but sputters and struggles more than I would expect for a car of this age.
Does anyone have any idea what the cause of this fault could be, or experienced before? Recommendations what they would do?
If I were to go back to the Ford dealership and ask for them to help, from my past experiences I would expect this to be extremely difficult and they would be reluctant to help. Do they have to help legally, as it appears to be the same fault that I notified within 30 days of purchase?
Obvious error.
The feedback for the turbo position sensor is goosed.
Replace it and it will be fine.
Route cause is the turbo position sensor - this is highly likely to be the primary fault code, and the others are generated as a result of this. (It's not logical for it to be any other way)
Why - sporadic and implausible fault from the turbo position feedback is confusing the ECU into 1 or possibly 2 errors.
Sporadic / implausible is likely to be an electrical issue, not a mechanical one. So.......
Either it sees the turbo position fault, and immediately goes into limp ....... or, it gets confused as to where the turbo actuator actually is, and mis-controls the turbo, resulting in a boost pressure outside defined limits, and goes into limp.
It's possible the wiring to the turbo position sensor is bad, but on a 19 plate car, this is unlikely, even for VW.
The feedback for the turbo position sensor is goosed.
Replace it and it will be fine.
Route cause is the turbo position sensor - this is highly likely to be the primary fault code, and the others are generated as a result of this. (It's not logical for it to be any other way)
Why - sporadic and implausible fault from the turbo position feedback is confusing the ECU into 1 or possibly 2 errors.
Sporadic / implausible is likely to be an electrical issue, not a mechanical one. So.......
Either it sees the turbo position fault, and immediately goes into limp ....... or, it gets confused as to where the turbo actuator actually is, and mis-controls the turbo, resulting in a boost pressure outside defined limits, and goes into limp.
It's possible the wiring to the turbo position sensor is bad, but on a 19 plate car, this is unlikely, even for VW.
t to cover inadequacies. I have an inkling that the position sensor might not be a separate item - ie, someone will need to change the turbo to fix. Madness if this is correct, but quite possible, and someone (presumably Ford) doesn't want to fork out to do this.
I'm an auto electrician who does lots with diesel engines, so I see stuff like this quite often. - but thanks for the kind words.
I'm an auto electrician who does lots with diesel engines, so I see stuff like this quite often. - but thanks for the kind words.
stevemcs said:
You can buy the actuators (electronic controlled ) on there own, we did a scirocco with similar symptoms last week - it also had one duff glow plug, both parts were around £330 fitted. Glow plugs are easy to swap and around £15 each. Actuator is genuine.
I was under the impression that it's a solenoid vac valve with a position feedback sensor on the actuator - hence VW changing the vac pipe - but I'm not 100% and you may be correct. And of course you may be able to change them. I remember doing a scirroco as well - about 2011 IIRC. Sensor has to read exactly 0.78v on idle, and rise to 3.8v or something at max output. Failure to meet the exact values will result in the ecu 'switching off' the solenoid, and needing to cycle the ignition before it would re-engage. In my Scirroco case, the bloke had remapped it, and made errors in the mapping....... So not entirely VW's fault. (on this singular occasion). 
I work for seat witch use the vw engines and there is a TSB for the turbo actuators. In the TSB it instructs you to insert a spacer between the turbo and the actuator then recalibrate the sensors. The reason for this is as the parts wear they start to exceed there tolerances and upset the sensors even though the parts are still fully functioning.
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