Fried PCM

[friedpcm]

I have a 2006 Mazda 6 Auto Wagon built for the Australian market.

On the weekend, I was towing a trailer (very light weight, I could hardly feel it) when the following started happening:

- Doors locking/unlocking
- Rear wiper working uncontrollably
- Couldn't change gears
- Speedo, tacho etc not working
- Horn going non-stop

I had the car towed to my local Mazda dealer and they said the PCM was fried. They replaced the PCM but have said that it is not covered by warranty because the trailer caused the PCM to fry. They said there was a "dead short".

I would have thought the PCM would have been protected by fuses so that this couldn't happen. I've asked a few people who have said the same thing.

Does anyone know for sure whether a short in the trailer could have caused this?

 

[skylinemonster]

i know we all strive to be righteous and honest individuals in this world but buddy there are some things you just turn the left cheek to and DO NOT DO and that is telling a DEALERSHIP of all people that you were doing something normal at the time this happened, which it sounds like you were. so they basically just used that against you. of course the ecu is protected by fuses or else every time you perform a task in the vehicle that causes the voltage to fluctuate, you'd fry the ecu. now your vehicle is flagged with this incident and now any future electrical issues that may arise with this vehicle are going to be like hell and highwater to get resolved, especially under warranty. how much was the pcm anyways, just curious?? I wish you would have told them that everything just stopped working and leave it at that, which in fact is what happened. you have to remember, they are in a business for one reason, to maximize profits, THEN take care of the customer.

 

[friedpcm]

Thanks for the tip.

Unfortunately, due to the type of problem it was, I couldn't open the back door on the wagon. Therefore, the trailer cable was dangling out for all the world to see... It would have been difficult for me to explain why I drive around with the cable hanging out...

So, do you think I should pursue it with them?

The cost to replace was $A604, including labour.

 

[ssinstaller]

Assuming your trailer harness had the parking lights, brake lights, and turn signals, all of those circuits are protected by fuses.

I'd ask them how any of those circuits even if they were damaged could possible damage the pcm when they are not connected to it, or controlled by it.....

 

[freekwonder]

Assuming your trailer harness had the parking lights, brake lights, and turn signals, all of those circuits are protected by fuses.

I'd ask them how any of those circuits even if they were damaged could possible damage the pcm when they are not connected to it, or controlled by it.....

Exactly. I would ask them to show you how towing the trailer fried the PCM. I could see it blowing fuses for the lights and screwing the lights up if it was wired wrong. And at the most wearing out the transmission if it over heated, but I don't see how it could fry the PCM. As the dealership to show you how it fried the PCM.

 

[friedpcm]

The Mazda servicer has sent the PCM to the Mazda tech guys so they can work out what happened.

As soon as I know more, I'll post it for those that are interested.

 

[freekwonder]

Yes please keep us updated. Would like to hear how it turns out.