Does Incorrect Rear Tire size cause Check Engine?

[drwhy]

I test drove a 30,000 mile 2004 MM today that the current owner had put the same size tires on all four. I turned off the Traction Control, but noticed just as soon as I pulled out of the drive, the there was a check engine light. I don't know if it came on just after starting the engine.

Does anyone know for sure the answer to the question in the title?

Thanks,
Tom

[Aren Jay]

Anything is possible but to be sure get a code reader and find out what it is for.

[red]

It should not. Here's what you'll see if the ratios are out of their thresholds (minus O/D OFF and LOW FUEL :D):

http://www.mercurymarauder.net/showcase/files/4/2/7/5/abs_tc_test-08.jpg

[red]

And, you could go for a test drive to Auto Zone (or another FLAPS) and have them read the code.

[drwhy]

Thanks for the reponses.

I just got a little more info from the owner. The Check Engine comes on from just starting the engine, before the car is even put in gear.

He was told by the service manager at a local FLM dealership that the Check Engine is set once the TC detects the rotation speed issue. But looking the at photo of the dash board in the previous post, there would seem to be some doubt as to whether the service manager is correct.

Any comments either way?

[red]

The Service Manager is incorrect. Your best bet is to read the codes and post up here.