Amarok idles higher than usual.

[Yehnahnope]

Hi guys,
After some info,
I have a 2013 Amarok Highline for the last 4 years been driving like a dream. Lately I’ve noticed that sometimes after a drive the idle sits at 950rpm instead of the standard 830ish rpm. If I turn the car off and then straight back on it goes back down to the standard 830rpm. It happens at random times, sometimes after a 5 min drive sometimes after a long drive. It’s not everyday though it is once a week at least. Have not noticed it doing this before. Taken it to VW last week and they said there’s no issues or codes, though I’m sure it hasn’t been doing this the whole time iv owned it. Any thoughts ?

[The_Hawk]

If I had to guess I would say it's the DPF doing a regen in the background.

[Lucas_R]

A lot of the 4 cylinder diesels do raise their idle when the DPF is doing a regeneration - so its possible this is what you are noticing. If you turn the engine off while this is happening do the engine fans keep running flat out for a while?

Otherwise, now that its starting to warm up people are using their air conditioner which causes the engine RPM to raise and drop a bit as the compressor turns on and off.

[Yehnahnope]

That was kind of my thoughts, though It’s just strange that I haven’t noticed this rpm rate before and it’s doing it even after 5 min drives.

I will have to check the fans next time it does this high revs.

The aircon doesn’t seem to be a factor as I have this on most times of the year, and putting it full barely moves the revs.

[Lucas_R]

Are there any driveability issues or lights on your dash when the revs change. A vacuum leak (a crack or rip in any of the many rubber pipes on the engine) can cause the idle to fluctuate so its possible this could be a factor. Does the engine still perform well (no loss of power)?

[Yehnahnope]

Seems to be performing as usual. No issues when driving, no vac hose cracks or problems. The only symptom is the high rev at idle at strange times. And it goes to the exact same ideal rate when it goes into the higher revs-950rpm. But again when it turn the car off and back on it goes back to the standard 830rpm. So the idle isn’t jumping around. It’s either the 830 standard or the higher 950.

[Lucas_R]

Ok im thinking its just the DPF doing a regeneration then. Do you notice the higher revs when stationary (eg at a traffic light) or only when you get home and put it into Park? If you notice it before you get home, try continuing to drive for another 10-15 mins and see if the revs go back to their normal level (a regen usually takes about 20 mins from start to finish).

A regen only normally occurs every X amount of km's (every car is different and can also be affected by how you drive the car - for example the V6 Amaroks do one every 300km or so and my car does one every 500km or so) but if you interrupt the process by turning the car off it will try and do one again the next day or perhaps the day after. So if this is occuring it may be why you are noticing the higher RPM happening more often. With all of the Covid lockdown and restrictions a lot of people have been having DPF issues due to constant short drives around their local suburb/area where the engine does not get up to temp and allow the DPF to do a regen properly like it normally would.

Also have a look at the info and links I posted in this thread the other day. Although this thread is for a V6 Amarok the info is still relevant to the 4 cylinder models. You can monitor your DPF for a small fee if you are interested, and also the Carista app lets you initiate a DPF regeneration at your convenience so you can avoid issues.

dpf fault with V6 Rok

[Yehnahnope]

Yeah seems the most logically at this stage.
The revs idle high when I’m stationary, eg a red light/stop sign. When it’s doing this high rpm thing.

[Lucas_R]

Yeah seems the most logically at this stage.
The revs idle high when I’m stationary, eg a red light/stop sign. When it’s doing this high rpm thing.

Ok well lets assume its doing a DPF regen when this happens. I suggest keep the engine running and keep driving for 15-20 mins once you notice the revs go up and then see if they go back to normal 830rpm. If so, then you can pretty safely assume its a regen in process.