Q: 1996 Olds Aurora OBDII P0603 PCM keep alive memory, car is in limp mode and running like it's off timing

asked by on January 26, 2018

I have a 96 Aurora, 8 banger 4.0 and it's running like it's firing on less than 8 cylinders because of an OBDII code P0603 Keep alive memory error/reset (translation, it's running in limp mode). I recently had the plugs and wires changed, oil, radiator flush, tranny filter, new battery, I dd find a loose ground wire that begins somewhere under the intake manifold cover and was bolted to the block, my mechanic must have accidentally broken it during the plug wire change. It's only about 16 gauge so it's not like a ground strap or anything, it must be a component ground, which could be throwing the code. I'm on disability so I can't just keep replacing parts, when this is clearly a connection issue. I need an honest mechanic who won't tell me to replace the ECM, as you can see, I do know my way around cars. Thanks much

My car has 118000 miles.
My car has an automatic transmission.

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Correct the ground connection first, in case that problem is a cause of the trouble code. P0603 does represent an electrical system fault. In practice, this particular fault might be found as battery terminal corrosion or loose connections, Keep Alive Power (KAPWR) circuit wire routing, an open wire in the KAPWR circuit, a damaged PCM, a charging system fault, ignition system faults causing secondary ignition voltage inference, and so forth. Basically, to diagnose this, a "decision tree" approach is used and if following that approach, the reference is the Factory Service Manual. If you want the required diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a Check Engine Light diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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