Changed key switch with used one now car won’t start
I changed out my key switch on a 2001
mustang with one off an identical car now
it won’t start....do I need to change pcm or
body control module to fix it
No the key communicates to the the tumbler and sends signal to to the pcm that this is the right key. What was the issue prior? Did you have ignition problems or did it not start? Because those cars have inertia switches to prevent it from starting if in event of being stolen or such
Providing that you are using right key. You may have to program the key and tumbler to pcm
The key is electronically "married" to the ECU. A trip to the Ford dealer or some locksmiths can resolve the issue.
Yes, I have seen this issue before. The key and the ECU are electronically coupled. It will require to go to the Ford dealer or a knowledgeable locksmith to solve the problem.
I bought the car with no key...I changed the pcm with the one off the donor car that I got key and ignition from...the engine fires just doesn’t get any spray from injectors
I don't see the correlation between the "donor" key and that there is no spray from the injectors.
No he is right! The key shuts down the injectors because the chip in the key powers both fuel pump and I believe power to plugs
Otherwise the key transponder does control that. Let me show you schematics
From the key to pcm
Pcm to Engine
What he was saying is he swapped both key and ignition and his question is shouldn't it start it?
I have a friend who works at dealer as a tech. He said 2 common faults. 1 is ignition switch or inertia switch. 2. Is wiring in cluster that burns out causes the car not to start
BrithishTech77, I thank you for your explanation and diagrams. One never stops learning!
