error P164D oil pressure

[rudzionek26]

T6 CXHA engine, 2017, 150 hp

I have a problem with the engine's oil pressure. While driving, the engine runs fine, and it runs quietly, but when I give it some pressure and then slow down and drive, around 2000 rpm, the oil light and warning light come on. I think the low oil pressure sensor might be faulty, either a green or brown sensor, meaning a brown sensor, or the oil pressure valve.

The pressure gauge showed at 80 degrees:

Idle 1.1 bar

1500 rpm 2 bar

2000 rpm 2.2 bar

2500 rpm 2.5 bar

I'm wondering if the valve is stuck in the low ECO pressure position?

I did the VCDS valve test and it came back positive!!

I think I'll buy two sensors plus the valve...

Have you done this?

VCDS error

16058 - Oil pressure switch for reduced pressure. Oil

P164D 00 [01101100] - Malfunction

Intermittent - Confirmed - Tested since clearing error codes

 

[rudzionek26]

I replaced two valve sensors and I still have error P0134d, I don't know what to do?

 

[manfrotto]

Did you work out what the piece you found in the sump was from?

And you changed both green and brown sensors (with genuine parts)?

 

[rudzionek26]

I couldn't determine where this component in the engine came from. So I replaced two, one green and one brown, plus the valve. Everything was purchased at a service center, not replacements.

 

[manfrotto]

Looking at the status of the sensors with teh engine runing at various revs, the low pressure sensor (IDE00497-MAS00628) is opening and closing throughout.
I don't think that is normal, and is likely causing the fault code. Perhaps @mmi could comment on whether it is normal or not. The actaul oil pressures look about right, so your oil pump is OK.
If you have changed the sensor, maybe it is a wiring issue. Did you check the wiring between the sensor and the ECU?

 

[rudzionek26]

The wiring is good, but I'm wondering about the pump's adjustment piston, which I pulled out to check. It has scratches, and maybe the pump isn't maintaining pressure. The oil is leaking sideways and not building pressure?

 

[DXX]

The wiring is good, but I'm wondering about the pump's adjustment piston, which I pulled out to check. It has scratches, and maybe the pump isn't maintaining pressure. The oil is leaking sideways and not building pressure?

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D

Post in thread 'Dreaded oil pressure switches'

2 Jan 2026

Maybe DXX is onto something if switches are failing on a regular basis - see post #35

Spool valves are bad enough with gear oil let alone filthy soot loaded engine oil, they have very tight machined tolerances.

• DXX

 

[DXX]

The wiring is good, but I'm wondering about the pump's adjustment piston, which I pulled out to check. It has scratches, and maybe the pump isn't maintaining pressure. The oil is leaking sideways and not building pressure?

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I think you may have found the reason, not sure that leakage would be the issue, more excessive friction.
Spool valves / servo pistons don’t work for long in contaminated oil and at that point in the oil circuit the only protection is a fairly coarse sump pickup strainer.
What mileage were the oil changes carried out?

 

[rudzionek26]

I recently bought the car, and this is my first oil change. I don't know how often the previous owner changed it, but I think it was every 30,000 km, as the car was serviced, and that's the interval. I change it every 10,000 km.

 

[DXX]

I recently bought the car, and this is my first oil change. I don't know how often the previous owner changed it, but I think it was every 30,000 km, as the car was serviced, and that's the interval. I change it every 10,000 km.

30000km would explain a lot.
Yet another plastic component that isn’t up to the job.

 

[rudzionek26]

I've seen similar pistons in ZF automatic transmissions and I've read that their failure affects gear shifting and causes gearbox failures, such as stalling or hard gear changes. This is due to low pressure in the gearbox.

 

[DXX]

Designing an oil pump is a very limited life is a sure way to guarantee vehicle disposal and new sales!
The material looks like Nylon 6-6, I’ve seen similar in PEEK which is also garbage compared with ground steel.
Probably a classic case of a supplier reducing unit cost in order to get the VW contract.

 

[manfrotto]

Out of interest, where did you connect the mechanical oil pressure gauge for the reading posted above?
I assume the one by the oil filter?

 

[rudzionek26]

Yes, at the oil filter, where the brown sensor is. Access to the green sensor is limited because it's a T6, not a Crafter.

 

[rudzionek26]

When I measured the pressure at the bottom of the filter, I wonder what the pressure was at the top when the light came on? The green sensor has a normal operating range of 0.3 to 0.6 bar. If VCDSS showed a signal and the oil light came on, the pressure must be less than 0.3 bar. I wonder if my cylinder head is seized? But it's quiet; I don't hear any metallic noises while the engine is running. I hope everything will be fine.

 

[DXX]

It’s crazy that manufacturers are trying to reduce oil pressures to reduce engine load, there are some things that you don’t save money on.
One of the reasons to keep the oil service interval at approx 7-8K miles.

 

[rudzionek26]

One thing still puzzles me. I know that companies that rebuild these engines in Poland, e.g., CXHA for the T6, install different oil pumps, which I'd say are better than the ones in the T6, according to ETKA 04L145208P. They replace the pump from a passenger car with, e.g., ETKA 04L145208T, because they're supposedly improved, don't make noise, etc. They only change the intake manifold and the gear. It's a hybrid.

 

[DXX]

don't make noise,

I don’t think your going to hear the oil pump over a 4 cyl’ 1.9 diesel.

 

[rudzionek26]

not 1.9 tdi but 2.0 cxha in T6 vacum apparently makes the most noise

 

[DXX]

not 1.9 tdi but 2.0 cxha in T6 vacum apparently makes the most noise

OK 2.0L but I’ve never heard anybody discussing a noisy vacuum pump before.
If it’s more reliable then great.