Amarok diesel problem

[andrew55]

Currently my rok is off the road for the past 3 weeks, the coily warning light came on & it went into limp home mode with very little boost, I managed to get it it to the mechanic however the engine check light had also come on. the scan tool came back with 4 faults P0236 turbo boost sensor, P0651 Sensor ref voltage, P1440 & P0403 EGR Ref & voltage codes. the earths at various points were cleaned & reattached. The EGR Cooler was also clogged, this was cleaned & reassembled. The rok was driven for 30kms all was fine. Hey presto drove out of the mechanics & the coily light came on & lost boost, promptly turned around & left it at the mechanics once again. Also have bench tested the turbo actuator & this was working correctly. This part had actually failed on my tdi tiggy at 97K. the rok has only done 75k, I bought it with 65k on the clock.
anyone got any ideas????

[Darkhorse Developments]

Ive had 2 like this and made up a new wiring loom between the turbo pressure sensor and the ecu. Cured both. (Might not cure yours!) Made up a 4 wire loom with new pins and either end and worked.

[andrew55]

thanx for the heads up darkhorse, hopefully will get a result soon & post.

[edi25]

if it's under warranty, vw will probably replace your turbos (mine were replaced at about 30000km from the same issue), as it's the whole assembly they replace. The fault was probably only the boost solenoid valve. I could switch the car off and back on, have full power again until the same conditions were met, then it would go back into limp mode with the flashing glow plug light. In my instance it happened at 100km/hr with cruise control on.

[andrew55]

at last a solution, the egr valve soleniod had a malfunction i.e. stuffed. solution was to replace egr valve assembly, cooler & assoc gaskets. total bill at VW dealership was a bit over $1600, including parts component of about $640. This was the 2nd one that the dealership had seen with the same problem. I must say great service even washed & cleaned the car inside & out.
It leads me to think a 3inch ss exhaust, egr blankoff & ecu reprogram may be the ultimate solution.

[andrew55]

50 kms max & back into limp home mode with coily light flashing with reduced boost; back to dealership, await with baited breath, not!!!

[andrew55]

picked up rok today, they reprogrammed the parameters in the ecu for the new egr valve, drove it for about 40kms, no problem, soon as I drove home after 20kmsl back into limp home. the new fault is low boost which I think is a furphy as it's the ecu trying to protect the engine from damagei!!!

[andrew55]

Picked up the rok twice this week, drove less then 20kms and coily light back on & back to the dealership. I think that they are thinking it could be an issue with the turbo or turbos. Been at dealership for 3 weeks as of yesterday. On Tuesday they checked the boost controller & it was recalibrated to factory specs, still no joy. edi25 may be right, unfortunately in my case no warranty. I have emailed VW Australia to see if they will offer any remedy!

[buzuki]

Id be looking at what darkhorse said.

[andrew55]

hi buzuki,
they checked that part of the wiring loom, all connections etc, could not find or generate a fault. It seems to be occurring at 2600-3000 rpm. does not generate a specific fault code.

[andrew55]

traded the rok last friday, lost confidence in this vehicle, dealership is going to replace the larger turbo, approx $3.2k plus fitting. I'm sure they will cover that in the resale retail price. This was an early build model 12/2010 so I couldn't justify sinking anymore hard earned into it. good luck to all the other owners of early build models!

[Gunbarrel]

Hi Andrew55
I am suffering from very similar symptoms, different fault code but equally irrelevant. Similar to EDI25 I go into limp mode at higher power levels, turn off engine and restart and its OK until the same conditions arise. I get a P087 low fuel pressure, tried a new pressure reg valve, no change, so took it to dealers. They got 20 grains of sand out of the bottom of the filter (had just come back from Canning Stock Route so hardly surprising), concluded "dirty fuel", their remedy is "we start at the tank and replace fuel components until the problem goes away". I figured I could do that at a fraction of the price, so tested the pressurising (lift) pump every which way and ok, replaced high pressure pump, pressure sensor all no change. It could not possibly be the injectors, any fault there would cause misfiring, spluttering etc, no sign of that in the slightest. Very detailed analysis of datalogs indicate the accelerator pedal going to idle setting approx 100msec before the fuel pressure shutdown, implying a fault there. So replaced accelerator pedal sensor, again no change, so now I am also stuffed for an answer, I have no faith in VW to find this, my evaluation is as per your experience, they just replace something and hope. It would appear that in your case having had the vehicle for 3 weeks they are also stuffed for an answer.

My evaluation of the fault code is that the fuel pressure control loop is tuned for the rate of change the pedal can produce, with a fault in the signal giving a very fast change, the control loop cannot respond fast enough and the overshoot causes pressure to go outside the tolerance and generate the fault code. Classic symptom in testing all this is that with the engine NOT running, I can put the ECU into limp mode by stroking the accelerator pedal, at 53% it triggers limp mode, but only starting from idle position. If the pedal is partly held down during the reset, then it does not happen, until position goes below 17% (idle is 14.5%).

If somone can make sense of this I would love to hear from you. Please........ Might try Darkhorse's technique, replace wiring. I am certainly grasping at straws by now.

[langers86]

I’ve had the same issue, replace all the vacuum lines from the turbo to the vacuum solenoids, they get old an bleed air.. easy fix[emoji106]


Sent from my iPhone using Tapatalk

[frednerkenstein]

I had a similar issue. It was the DPF. I spoke with VW about it (it had 1000km on the clock) and was told it was a driver profile error!!