Nailhed66 Posted July 3, 2021 Share Posted July 3, 2021 E042 code, warning message and engine light keep coming back even after replacing the coil pack,spark plugs and wires with AC Delco or oem spec. the system seems to reset and the car will run great for awhile and then the computer rears it’s ugly head again. Any ideas ? Link to comment Share on other sites More sharing options...
Ronnie Posted July 3, 2021 Share Posted July 3, 2021 Code EO42 is the cam magnet sensor. Probably caused by the magnet that triggers it has fell out of the cam sprocket. Common problem. There is an easy fix for replacing the cam sensor magnet without tearing into the engine listed in the menu at the top of the page. 1 Link to comment Share on other sites More sharing options...
Nailhed66 Posted July 3, 2021 Topic Author Share Posted July 3, 2021 44 minutes ago, Ronnie said: Code EO42 is the cam magnet sensor. Probably caused by the magnet that triggers it has fell out of the cam sprocket. Common problem. There is an easy fix for replacing the cam sensor magnet without tearing into the engine listed in the menu at the top of the page. According to the chart EO41 is the cam sensor circuit and EO42 is ignition system which is why I was hoping a tuneup would solve the issue. Thanks for your reply 1 Link to comment Share on other sites More sharing options...
Ronnie Posted July 3, 2021 Share Posted July 3, 2021 Sorry. You are correct. I should have checked the code chart before responding. You will probably need a Factory Service Manual to track a code 42 down. I don't remember anyone having that code. 1 Link to comment Share on other sites More sharing options...
Padgett Posted July 4, 2021 Share Posted July 4, 2021 (edited) There is a trouble diagnosis tree in the 8D1 section of the FSM. That said, " after replacing the coil pack," makes me suspicious, the 14 pin connector with the single screw is notorious for not making good contact. I'd first try just pushing in hard at the ends. If comes back, remove the pad in the connector. Edited July 4, 2021 by Padgett 2 Link to comment Share on other sites More sharing options...
fun car guy Posted July 4, 2021 Share Posted July 4, 2021 my '89 coupe is still running on the original Magnavox coils. Maybe an upgrade is called for? Link to comment Share on other sites More sharing options...
Nailhed66 Posted July 4, 2021 Topic Author Share Posted July 4, 2021 1 hour ago, fun car guy said: my '89 coupe is still running on the original Magnavox coils. Maybe an upgrade is called for? It turns out that the coil pack was probably not the issue. I replaced it with an oem magnavox along with oem spec. plugs and wires hoping that would solve the issue. Process of elimination. As Padgett had mentioned the 14 pin connector,that will be next thing to pull off and inspect. The E042 code and message warning popped up on my way home from a trip to the mountains where I pushed the car hard for three days. I noticed the 14 pin connector and wires are right up close to the lower radiator hose so I’m thinking prolonged high heat may have been a factor. Thanks for your response Link to comment Share on other sites More sharing options...
Padgett Posted July 4, 2021 Share Posted July 4, 2021 I prefer the Delco ignition. Have felt the pins on the 14 pin connector are too short and have removed the pad on mine. Finally wound up building a breakout box so I could monitor each pin. 2 Link to comment Share on other sites More sharing options...
Ronnie Posted July 5, 2021 Share Posted July 5, 2021 If I read the FSM correctly, a code 42 is basically telling you that the ECM isn't receiving the information from the ICM it needs to take over control of the ignition timing. That could be caused by a bad connection to the ICM or bad wiring between the ICM and the ECM. Even though the engine may be running smoothly, it probably isn't performing as well as it should if the ignition timing isn't being determined by the ECM. 1 Link to comment Share on other sites More sharing options...
Nailhed66 Posted July 5, 2021 Topic Author Share Posted July 5, 2021 1 hour ago, Ronnie said: If I read the FSM correctly, a code 42 is basically telling you that the ECM isn't receiving the information from the ICM it needs to take over control of the ignition timing. That could be caused by a bad connection to the ICM or bad wiring between the ICM and the ECM. Even though the engine may be running smoothly, it probably isn't performing as well as it should if the ignition timing isn't being determined by the ECM. Thanks for taking the time to check the manual, this is very helpful information 1 Link to comment Share on other sites More sharing options...
Nailhed66 Posted July 5, 2021 Topic Author Share Posted July 5, 2021 2 hours ago, Padgett said: I prefer the Delco ignition. Have felt the pins on the 14 pin connector are too short and have removed the pad on mine. Finally wound up building a breakout box so I could monitor each pin. It seems like you’ve been down this road before… when time permits I’m going to see about removing the pad from that connector. I appreciate the helpful information from you and Ronnie. At least now I have some clues 1 Link to comment Share on other sites More sharing options...
Nailhed66 Posted October 22, 2021 Topic Author Share Posted October 22, 2021 Update - a new 14 pin connector and wires have been spliced in and re routed away from the radiator hose. This seems to have solved the problem. The car is running great and the warning message and engine light are finally gone ! 1 Link to comment Share on other sites More sharing options...
Ronnie Posted October 22, 2021 Share Posted October 22, 2021 Thanks for taking the time to let us know. It might help someone else in the future who reads this. 1 1 Link to comment Share on other sites More sharing options...
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