2017 Skoda Kodiaq Coolant leak through wiring harness to ECU

[xiao]

2017 Skoda Kodiaq

Coolant leaking up the wiring harness into the ECU socket. Now causing many other issues. Now, sometimes no response from acceleration, rough engine, or rough change of gears. Power issues. The mechanic changed the coolant pump and temp sensor. And cleaned corrosion off the pins and sockets for the ECU. Also tried a replacement ECU.

I don't know what to do. I called Skoda service guys they said the next available date to diagnose the car is in December.

 

Issue History

I had 3 cigarette lighter fuse blow in less than 3 weeks. I assumed I might have an electrical issue.

 

Soon after an engine check light

I got a diagnostic reader to find the fault

The faults found were P261A and P261C, which relate to the coolant pump, so I keep an eye on the coolant temps and oil temps to ensure things are not overheating.

 

I took it to the mechanics and told them about the fuse for the cigarette lighter port and this check engine light.

They had a look and said the coolant pump is not working, so we will need to change that. Which they said they did. They said the fault is still showing up, so they will give the car to another mechanic shop, a VW & Audi specialist. These guys had a look and said there is a problem with the wiring and we will fix that. I collected the car, and the error came back. They kept the car for another 2 hours to take a look, and they said they changed the wiring on the ECU side too.

I was charged a total of £750

 

One week later, The check engine light is back with the same fault. They said to bring it back and they would fix it under warranty if it is the same problem. I took it back to them and they said no it is not the same issue, the coolant temp sensor is failing and there is coolant in the ECU socket. They showed me a photo of the ECU plug and socket with coolant, and it is corroded. They said they changed the coolant temp sensor and cleaned out the ECU socket of corrosion.

Charged another £350

 

A week or so later, I felt the car was not changing gears smoothly, and then I saw the EPC light on the dash. Now the car is jerking when changing gears, not giving power, and other warnings that showing on the dash. Something about parking brake issues etc. I put the car into park and the car would still roll. Other errors like Park Pilot not working etc.

 

Now I think that the coolant in the ECU socket has messed up the ECU itself. So I bought a new ECU, with the service of cloning my old ECU to the replacement. I drive the car for 30 or so minutes, and all of the errors start again. The car would have power issues, the engine running rough, almost like it is in limp mode.

Faults, P2122; P0641; P2562; Traction Light, EPC light, Low Tire Pressure light, Check Engine Light. Messages on Dash, Front Sensor Unavailable.Fault Eletronic Parking Break, Error Hill Hold Assisist. Few Others.

[Ootohere]

I see that it had done 37,000 miles 2 1/2 years ago, how many miles on it now?

[xiao]

55 minutes ago, toot said:

I see that it had done 37,000 miles 2 1/2 years ago, how many miles on it now?

It's on 64k miles now

[J.R.]

Lots of people have been taking you for a ride, ask them where you can buy some gravity defying coolant to replace the stuff that leaked out and climbed its way up the wiring loom to the ECU tucked away at the highest part of the scuttle.

[Breezy_Pete]

Coolant under pressure can get through a faulty coolant temperature sensor that has become porous @J.R..

Thereafter it is confined within the waterproofing of the connector, except via the gaps between the wire strands of the conductors. Wicks along to other end of wire and through into the connected item at t'other end.

Reported more than once on here. I'll try to find an example thread tomorrow if I remember. 

 

 

[J.R.]

Yes I can see that is plausible, I stand corrected, has it ever been reported to have made its way up to the ECU connector? Is there another sub loom connector before that?

[Breezy_Pete]

Yep, the thread I saw most recently was coolant inside ECU connector, traced back to wetness inside CTS connection. Mk1 Fabia I'm fairly sure.

Maybe 2 or 3 years ago.

[Breezy_Pete]

5 years ago, it seems: 

 

[ApertureS]

22 hours ago, J.R. said:

Yes I can see that is plausible, I stand corrected, has it ever been reported to have made its way up to the ECU connector? Is there another sub loom connector before that?

Very common on Vauxhalls where the oil pressure switch failed, forced oil up the inside of the wire and insulation and into the engine ecu.

 

I’ve also seen a bmw do it with coolant via one of the external water pumps, made a right mess!

[J.R.]

Thanks for putting me straight gents!

[xiao]

What's the solution?