As you said, it could be a number of things. The ICM is one of them. The ECM controls the electronic spark timing, but it gets its references from the crankshaft sensor and the camshaft sensor. The ECM then tells the ICM to spark. I guess technically it could be any of these, but as Padgett suggested the ICM would be his first guess.

The cam and ECM should set off error codes if they were busted, and I'm pretty sure the car won't run if the crank sensor is out, which leaves the ICM.

Don't hold me to it, someone else will probably come by with a better explaination.

a) bad crank sensor and the car won't run
b) bad cam sensor and you get a code 41 but it runs
c) bad knock sensor (mushroom thingie in back of block below #2 spark plug) could cause a code 43 not code 42

See page 6E3-A-80 in the 90 Bonneville service manual (or code 42 in section 6E3-A of any 3800 manual) for full description and troubleshooting chart for code 42 but is basically caused by one of three things
- bad ignition module
- bad ECM
- bad ckt 424 (wire from Ign Module pin B to ECM pin BC7).

First thing I'd do is to R&R the harness on the ignition module
Second thing would be to toss the Magnavox (or keep as a spare) and get a Delco.

<rant> Anyone who expect to keep one of these cars running past the first decade should have a copy of the service manual. If you can't afford one, arrange to download sections 6 and 8 at a minimum from http://www.reatta.net/docs.html. Use 90 FSM for "C" engine and 91 for "L".</rant>

Padgett..... car starts up great and still runs ok. Rides and idles a little rough since SES light came on. I guess I'll start with the ignition module......Don't have one of those manuals....any of these manuals online???
Thanks

Chiltons and Haynes make one, you can find them at Wal-Mart, Auto Stores, Book stores, etc...But your best bet is a factory service manual. They can be purchased online and found on ebay. The FSM is a little more technical, and the other two are more basic. Usually a combination of a FSM and a Chiltons or Haynes book will do the trick.

For time being, heres the easiest way out.

Thanks capn.....Not sure if all that has to be replaced though...I'm thinking its just a sensor..since it starts up and runs...Its obviously not a crank sensor though...of course the kid at autozone could have read the code wrong..who knows it could be a 41 or 43.....grrr...this is frustrating..LOL
Of course if it is indeed a 42 and I trust it is...then its either a bad ICM, ECM, or Ckt 424.....Damn those modules are way more than I had intended seeing how autozone says it could have been any 3 kinds of sensors that are 5 - 30 bucks......
I wish I knew more about this stuff...

Read the codes yourself man. Remember that URL I gave you earlier? Extract 'em yourself and read em yourself. I am surprised the idiots at Autozone could count to 43, let alone read a flashing light like that. It may get confusing.. so yeah do it a few times if you must.


-justin

Get three to www.helminc.com . The Factory service manual sale has been extended to 30 April and they have the 1990 manual (only one I looked up) for $30 plus about $7 shipping. Can get several manuals for about the same price. All of the things that the Haynes manual says are "too complex for the owner" are in there.

Have nothing against a Haynes or Clymer or Chilton (but like Haynes better), I usually keep one under the seat on trips. Is about what they are good for. However I do have a factory service manual at home for every car we own.

BTW the only "scan tool" you need to read the trouble codes is a paper clip and the ability to count to nine (there is time to move your lips). I keep several devices around because there is much more information available than just trouble codes.

Don't downrate the guys at AZ, they try very hard but have to keep track of every car made and few people have 15 year old dinosaurs. Besides here they are open 24/7 and usually have what I need.

Is odd what they don't have though - try buying some sunroof drain hose - I wound up at home depot (where an idiot on a cell phone backed out of a parking place into my door while I was stopped waiting for another person to move (saw the lights, was boxed in, OP ignored air horns "didn't think it was about him..." At least no difficulty with his insurance company.

I must be dreaming... $30 is downright a steal. How often do they sell the manuals for 1/3 of their normal price? There should be a BIG post in the Gereral forum alerting members to this.

*runs to get wallet*

All the time, I think I paid $40 total for mine.. or maybe $50. Not sure, but yeah


-justin

Was at the dealer today with my GTP....Asked about the Code 42.....by the way I did for sure get a code 42 when I re-tested it. Because the car starts and has been running..I'm going to assume its the ICM. I will replace this at which time I will replace the coils as well. This seems like the only reasonable thing...... Anyone disagree???