2.0TSI VRS EPC light with Oil pressure switch malfunction?

[TeebsVRS]

Been having a few issues with my car lately including coolant leak, timing correlation codes, very poor cold start, coolant temp gauge malfunctions and erratic cabin heating performance.

 

Thought my local garage had got to the bottom of everything with a new water pump, timing chain kit, 2 X magnet solenoids and a new coolant temp sensor after which it seemed to be running well again, apart from erratic cabin heater performance.

 

After driving it for 10 miles or so yesterday car for the first time since all the work, it went into max 4k rev mode driving very low on power, EPC light on and start/stop error on the vehicle info screen.

 

Had VW assist out once home and a diagnostic scan showed a sporadic fault with P168D oil pressure switch 3 malfunction and also P16C1 heater support pump open circuit.

 

Has anyone had these codes before?

 

Car is 64 plate 2.0TSI VRS with 109k miles.

 

[TheClient]

Not had the faults myself but seen and read a lot on the various oil pressure faults that can occur on the ea888 gen 3.

 

That oil pressure fault is nice and specific for the level 3 switch, which is the piston cooling jet circuit. It is located front RHS near the coolant pump. 

 

Given it says malfunction, the first check would be the switch to be tested or replaced and wiring checked. But I have seen malfunction reported when there was a genuine oil pressure out of range issue, so it could be a good idea to test the actual oil pressure at the switch location with the piston cooling jet control valve disconnected. This activates the cooling jet circuit. The control valve when activated, stops flow to cooling jets, this happens in most normal / light duty driving. There is a specific set of parameters for engine speed, temp and load that is used to define operation.

 

On the second fault, that could be playing a part with your heating performance although the support pump is only really called for in start stop operation to provide cabin heat as I recall. If its reported open circuit, the wiring is faulty / disconnected or the electric pump motor is dead and needs replacing. 

[TeebsVRS]

Thanks @TheClient, I did some deep googling as I couldn't sleep for a few hours stressing about the car. Found a video explaining the relation to the sensor 3 and the cooling jet system, and in that car with the same fault it turned out to be the camshaft. Then found another depressing video where an audi engine with similar fault code had chewed up various internal oil mesh filters and caused lots of internal blockages and damage.

 

I have noticed over the last couple of years it has used a fairly high amount of oil between services.

 

Really hope it's just electrical fault as I've spent over £2k on the car in the last month 😭

 

If the other fault is just for cabin heating I might leave that for now. I do get heat through, but seems to fade when stationary or at low revs.

 

I'll see what the local garage think, but may just bite the bullet and send it in to the best VAG specialist in the region.

[TheClient]

Yes, there's a fairly small but serious smattering of oil pressure related faults that are lurking out there.

 

Some of the horrors you read about maybe the gen 2 though.

 

At the moment, in absence of further testing, I'd be hopeful it will be a fix with wiring, the switch or maybe the oil cooling jet control valve that controls oil flow to a mechanical solenoid for activation. 

 

As long as your local garage can locate those three items and do some sense checking and maybe replace or test the switch as a first step, that should be OK.  Or you could probably replace the switch as a DIY, and see what happens with fault cleared.  

 

Maybe the support pump does actually run at other times other than when in start / stop when engine not running as well - that would explain your heat issue at low revs. 

 

Edit. How much oil is it using per how many miles? 

Edited 10 December, 2023 by TheClient

[TeebsVRS]

@TheClient I've not reliably measured, I feel like it had to have most of a 4litre bottle between annual services (10-12k miles) which I believe is well within VWs bonkers tolerance levels of 1l per 1200miles on this engine.

 

The original coolant leak at the 'stat had leaked onto a multiplug but had been checked and cleaned out, also the coolant temp sensor on the head also had damage to wiring due to coolant ingress.

 

Hoping it's a continuation of wiring issues rather than physical engine damage.

 

 

Edited 10 December, 2023 by TeebsVRS

[PetrolDave]

5 minutes ago, TeebsVRS said:

Hoping it's a continuation of wiring issues rather than physical engine damage.

Best way to check whether the oil pressure is OK is to temporarily fit a genuine mechanical oil pressure gauge.

[TheClient]

1 hour ago, PetrolDave said:

Best way to check whether the oil pressure is OK is to temporarily fit a genuine mechanical oil pressure gauge.

Agree but some care is needed to understand what you are seeing. For example, by default at low revs and idle piston cooling jet control valve is closed and there should be no oil pressure at the switch. That test under those conditions doesn't prove an oil pressure issue. 

 

Of course, in a DIY environment, it can be just easier to replace or test the switch and go from there. A guage helps though and clearly a garage would have one as long as you know how to test and how!