Can excessive heat in the engine compartment cause the PCM/ECU to fail?
Here’s a long story made as short as possible.
I purchased a cherry used Saab 93 with only 30,000 miles on it.
i’ve owned Saabs my whole life.
Within three weeks of ownership I was unable to avoid a tread from a tractor trailer lying on the highway.
It took out my spoiler, cowling, and slightly damaged the radiator.
The body shop authorized a radiator replacement.
Within 1 week of getting the car back from the body shop ( in the early spring), the engine would overheat under excessive load.
Hills and such.
So much the the A/C would automatically shut and warn me of the situation.
I took it back to the auto body shop.
They could not duplicate the issue.
Said they couldn’t find anything wrong.
Told me it was likely an “air bubble” and it should work itself out.
About three weeks later the outside temperatures rose significantly.
The car now started overheating constantly.
Once telling me to immediately pull over.
I found that venting the engine heat into the cabin would instantly bring the needle down to safe operating temperatures.
I limped to the body shop.
They had it for two days.
This time replicated the situation, but could not find anything wrong.
They sent it to the local Saab guy.
They duplicated the issue instantly and took all of 5 minutes to isolate the problem.
The body shop had left a cap on the hose.
Actually the cap had worked it’s way inside the hose so that they could attach it to the radiator, but the cap was still inside the hose.
Water did not circulate for 6 weeks.
The body shop accepted responsibility and paid for repairs.
But this engine had only 30,000 miles on it, and I was concerned that thermal stress would manifest itself moving forward.
They have reluctantly agreed to handle any heat related issues.
I told them I wasn’t looking to nickle and dime them, but felt the should bear some responsibility for heat damage.
Low and behold, driving to work this morning – just 10 days since the repair – my PCM/ECU failed.
Car shut off. Done.
Codes indicate the problem is a defective PCM.
So I do a little investigating.
There are not excessive reports of the ECUs on 04 Saab 2.8Ts going bad.
I also learn that one of the biggest reasons they fail is thermal stress causing micro-fractures on the circuit boards.
And it sounds like they may be susceptible to extreme heat.
I have not contacted the body shop yet.
I’d like some input before I do.
I’m not looking to nickle and dime them.
What say you?
Do you think the issue could be caused by thermal stress ?