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Ignition/Key Resistor


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I was driving my '97 Eldorado today and the DIC flashed a message: "CAR MAY NOT RESTART - THEFT SYSTEM PROBLEM". I pulled over, shut down, got out and locked the doors with the remote and then re-entered and started the car with no problem. The same message returned, but disappeared and has not re-appeared since. I've had several startups since with no return of the message.

I ran for codes and the following two returned: PCM 0603 H and IPC B2781 H. Both are history codes; the second one relates to a bad resistor. I imagine the ignition key resistor might have been faulty, after all it's 12 years old now. I called the dealer for a price on a new key, but he said I need to replace both the key and the ignition cylinder for around $350 or I risk the car not starting one of these days.

Might this have been a fluke, or is it just a matter of time before I'm stranded somewhere? Has anyone had any similar experiences? The dealer said this is very common and that I should replace the keys and cylinder ASAP. Just looking to see if anyone else has had this experience. How much time do I have to play with here?

Thanks to all,


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I would go ahead and replace it. I have replaced mine twice in 135000 miles. Once was the same issue as your seeing, the other time it just refused to start. Both times it was the wire in the cylinder.

Good luck.

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The resistor contacts on the key wear down over time. The warning on your DIC and the code

B2781 Wrong Resistor After Good

mean that the electrical contact is getting flaky. This has happened to me several times because I have about 5 pounds of stuff on my keychain, and the first time I did let the dealer sell me an ignition lock replacement. Now I walk up to the parts counter and ask for a key and that solves the problem for a couple of years.

If the key gets turned to Start without the resistor making contact, it will not start for 3 minutes. If that happens before you get a new key, or if you keep having DIC messages and codes after you buy a new key, then you might consider getting the ignition cylinder replaced.

The code

P0603 Control Module Long Term Memory Reset

means that your battery was disconnected recently.

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I had the message once on my '97. I bought a key online from marcslockandkey (I believe it was) for $5. You will need to measure the resistance of the pellet first. Then I had it cut at Ace Hardware for $1.

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