2020 ECU Problems Caused by Windshield Washer Fluid Pump

I bought my third GEN 2020 Tacoma used with 8200 miles. After two weeks, I had a low brake power alert that would not clear. I took it to the local dealership and they’ve had it for a week. I found out today that the windshield washer fluid pump was leaking on the engine ecu wiring harness. The harness had been replaced prior to me owning it. Has anyone else had alert issues with a weak windshield fluid spray? This might be the cause.

 

That sounds like a bad harness. An OEM harness should be reasonably water resistant.

 

I would think so too. But for it to occur on the original and then the replaced harness seems strange. The dealership that did the original warranty work did not replace the washer pump when they changed out the wiring harness.

I’m sure the original owner got tired of leaving it at the dealership for warranty work and got rid of it. Hopefully I won’t have any other issues after it’s fixed.

 

This is the official write up from the dealership.

 

Sounds like it's a leaking windshield?


EDIT: or from the cowl?

 

Nice job that tech did, getting to the root cause of the problem. The last sentence in his write up is a little concerning, but hopefully he got all the greenies/gunk out of that connector

 

They told me it was a unicorn. They had never seen it before. The water was pushed up through the electric motor of the washer pump and leeched through the wire to the ECU connection. The previous owner took it to another dealership and they replaced the wiring harness 2 months ago. It already had rust stains on the connection.

 

So the water went all the way from the passengers front engine bay by the headlight, all the way to the interior of the cabin? Damn that's a bad ass tech to track that down.

 

Yeah no flies on that guy lol.
He could have been tipped off by the smell/colour of the fluid at the opposite end of the harness, or noticed fluid in the washer pump connector.. still, hell of a job sorting that out!

 

And thats why I wouldn't bet a single penny on that diagnosis, a diagnosis that took a week to make???

Best of luck with your situation and hopefully someone will find the real cause.