Hello everyone, I have a problem with my 2022 Skoda Kamiq, 1.0 Tsi engine. It's the auxiliary cooling system pump (part number 5q0965567N). It runs constantly and drains the battery. After locking the car, the pump goes silent for about 2 minutes, then turns back on and runs continuously. After unlocking the car, the same thing happens; the pump stops working for a moment, then turns on and runs continuously. The question is, what controls it? The temperature sensor has been tested and shows a good temperature. I'm asking for suggestions and help in solving the problem.

Engine code or VIN would help, but I expect you'll find 3 wires going to the pump connector, a brown earth wire, a blue 12V feed, and a blue/yellow control wire from the engine ECU, pin 21 of the 60-way connector.

The blue wire is fed via fuse 2 in engine bay, which is from the output of the 'main relay' J271 (Relay position 6 in engine bay) , which is also controlled by engine ECU.

Edited 26 July, 202526 Jul by Breezy_Pete

Hi, here's my VIN number: TMBGR6***********. I had a damaged part of the wiring harness, but all the cables were repaired. So the pump is controlled by the engine computer and a relay?

I will re-check the wiring info now that I have the VIN.

Not sure who obliterated the VIN, but luckily I had left the page open on my phone, pre-edit.

Wiring and relay are as described earlier.

If no problem can be found with any of the three wires or the connector at the pump, I think maybe replacing the relay might be the easiest thing to try.

The wiring diagram, indicates that there is a servomotor on the radiator 'blind' assembly, which shares a 12V supply from fuse 2. Was that damaged?

The radiators were damaged, along with the fan. I don't know what this servomotor is? The radiators and fan were replaced. I'll try to check the wiring of the pump itself today. I'll try to locate the relay and disconnect it to see if the pump stops working.

Do you have a description of the relays in the engine compartment? Or can you show me which relay number 6 is?

I checked the wires and there's continuity. I also checked the wire from relay 645 pin 1 to fuse 2 and there's continuity as well. Now I just need to buy a relay and test it.

Sounds like I'm too late with this, did you find numbering on the sockets where the relays fit?

Thank you very much for your help. I figured out which relay it is. Now I need to buy the relay and try replacing it. I'm wondering because I still have power at the pump. After plugging the connector into the pump, it works immediately, even though the key is removed from the ignition.

One way that relays fail is that the contacts stick (weld) together when they should be apart.

The relay probably should stay energised (contacts together to power the fuse and pump, and several other fuses and other items), but only for a short time after key is removed, so that this coolant pump can run for a short time after switch-off, if the engine ECU decides it is useful.

I just checked the relay from another car, and it's the same thing. So the relay is fine. But when I lock the car with the central locking, the pump turns on after about 2 minutes, but when I pull fuse number 10, it turns the pump off.

Strange.

(Engine bay) Fuse 10 is a permanent 12V supply to the battery monitor control unit, according to the circuits I am looking at.

I don't know anymore. What is this servomotor? Are you talking about the electric shutters in front of the radiators?

Yes.

It was damaged and I just replaced it. I thought it was missing and not working properly. Unfortunately, the problem persists. Do you happen to have a wiring diagram? Any other ideas? I wonder why there's constant 12V there, but after locking the car, it disappears for 2 minutes and then reappears.

Edited 27 July, 202527 Jul by mlody38

For the pump to be running when it should not be, there are only really two possibilities.

1. The control signal from engine ECU says 'run pump' at a time when it isn't really needed (for reasons we can't see easily), and the pump has its power feed because the relay is switched on, or

2. The relay is switched on when it should not be, and the control signal says 'run pump'.

I don't know which.

Sometimes electronic modules have 'emergency state' defaults if the control signal is not within expected parameters while the module is powered, and that state is usually the one that minimises the chance of engine overheating.

I have told you all of the directly related wiring. You can download wiring diagrams for every variant of Kamiq from erWin Skoda if you spend a few Euro.

Master, I can't thank you enough. It turns out my mechanic messed with the fuse box. The pins from fuse no. 2 to no. 10 were swapped, and they're on a different power rail, so the pump was constantly powered. I should add that the wire colors are the same (yellow and red). You've guided me. Thank you very much.

Brilliant news! Well done.