Hi everyone,

I’m having an issue with a 2019 Skoda Rapid 1.0 TSI (DKLD, 95HP). The idle speed stays at around 1400 rpm and doesn’t drop after the first 30–60 seconds as it normally would. The engine sounds a bit louder and the instantaneous fuel consumption is higher during the initial warm-up (which is normal), but the revs just don’t come down afterwards. The battery has recently been replaced, and the spark plugs were changed last year.

I’ve been to two garages so far (including a main dealer), but they couldn’t find anything wrong. No fault codes on diagnostics, all parameters look fine, no warning lights on the dash, and the car drives normally otherwise. The ECU software version has been checked, adaptations reset, the car was left overnight with the battery disconnected, and the intake hoses were inspected — nothing found. Instant fuel consumption at idle is about 0.7–0.8 l/h.

I also did a 120 km motorway run in case it needed a regeneration, but it made no difference.

Has anyone else run into this, or have any ideas what might cause a high idle like this?

I've noticed that my wife's 2015 VW Polo 1.2TSI 110PS 6MT does, frequently especially in colder weather, after it has warmed up, idle above "normal" idle speed.

It does that even when the cabin fan is switched off - so that discounts "cabin set temperature" as being the issue, also, when it last did it, I switched back on Auto Stop/Start - and the engine stopped - so that discounts "battery state of charge", the headlights were also not on Auto and switch off. Some time I'll use VCDS to check other possible reasons for this like incorrect oil temperature.

Edited 8 February8 Feb by rum4mo

The main dealer assured me that all parameters were checked. Another mechanic inspected the intake valves and other possible sources of unmetered air, but without any conclusion. I replaced the battery as well, mainly to rule out any issues related to electrical consumers or low voltage.

Hello, welcome to the forum.

Does it still do this once the engine has warmed up?

Does the temperature gauge react to engine temperature changes normally?

Hello! Thanks for your reply! Yes, it does, even with a warm engine. Regardless of conditions, the revs don’t drop. On the other hand, it seems to respond correctly to load in every gear, turning on the air conditioning, etc. The temperature gauge appears to be reading correctly.

I'd suggest getting another DTC scan done - quite likely there is a faulty sensor giving incorrect data to the ECU.

Might be as simple as a bad accelerator pedal sensor or perhaps vaccum leak/coolant sensor.

Alasdair

Might be as simple as a getting older car / GPF. High idle has been reported with 1.0 TSI Fabia with GPF. @VMG What country are you in and what ambient temperatures have you been having. With a Petrol & a GPF the Reggening is not done as it is with a Diesel & a DPF. It does it after hot and off the accelerator. decelerating.

It turns out it was something much simpler. The PCV valve wasn’t functioning properly and the GPF couldn’t regenerate. After replacing the valve, the issue resolved itself following a 20 km drive.

Hope this helps someone else in the future. Cheers!