2019 Octavia VRS petrol manual. 54,000 kms (33,000 miles). Started the car yesterday and both EPC and check engine lights came on along with max revs display. Temp gauge showed high reading very quickly, and car in limp mode. Checked coolant level and oil level and both OK. Parked car and left it for a couple of hours. Faults remained. Any ideas, or should I just limp it along to the service agent? I do not have access to a code reader. Car is regularly serviced. TIA.

Edited 17 August, 202517 Aug by NZedder

Kia Ora, did these anomalous gauge readings and fault indications appear immediately the engine was started? If so, probably a sensor or electrical issue - see if you can get a mobile mechanic to come out to read any DTCs logged.

@NZedder We really need a scan via VCDS or ODBEleven to make sense of the issue. EPC light covers a multitude of sins.

If the temperature raises, it is probably the water pump impeller that has failed but again you still need a scan to get the best diagnosis. Get yourself an ODBEleven scanner for proper diagnosis.

Thanks all. Yes - fault indications appeared immediately after starting the engine. Will see if I can get it scanned.

That being the case, it is extremely unlikely that the engine was actually overheating.

You said in your post 'with max revs display' - was the engine actually revving at high speed - or did it sound as if it was running at normal idle speed, with just the rev counter giving an apparent false high reading?

No - the engine was not revving high. Display said something along the lines of "do not exceed XXX revs" with XXX revs number getting lower with time. Engine did not feel excessively hot - no sounds of boiling etc. Got hold of a code reader and get P00B7. Coolant level fine, so maybe water pump issue (did take a couple of kms for the overheating warning to show).

Rather confusing as you previously said that the fault indications appeared immediately the engine was started!

Thanks Warrior193. Apologies if confusing. Timeline is as follows. Start engine - immediate 'Check Engine' light on, then less than a second later, EPC light on and warning re not exceeding XXX revs flashes up. Drive for a km or so and temp gauge rises rapidly. Car in limp mode. After about 1.5 - 2km temp gauge approaches red and overheating warning flashes up, at which point I park the car. Left it for two hours then drove it home (about 1 km) with car obviously in limp mode, warnings still showing and temp gauge climbing towards the red.

Edited 19 August, 202519 Aug by NZedder

Suggest looking at coolant pump or any associated flow sensor.

Very very likely to be the electro mechanical thermostat. Commonly referred to as a water pump issue because the water pump is bolted on the side. It almost never is the actual water pump though.

You can monitor actuator angle with a proper scan tool. Often what happens is the leak will kill the pcb and then the thermostat will not work.

Thank you. That makes a lot of sense.

On 20/08/2025 at 18:23, TheClient said:

Very very likely to be the electro mechanical thermostat. Commonly referred to as a water pump issue because the water pump is bolted on the side. It almost never is the actual water pump though.

You can monitor actuator angle with a proper scan tool. Often what happens is the leak will kill the pcb and then the thermostat will not work.

Thank you. Your diagnosis was 100% correct.