trouble code 53 & 23

[TammyW]

Hello, I have a 90 lumina 3.1 with 180,000 miles. Lately it has started running real rough & dying, although it seems to start ok on other occasions I have to floor the gas pedal to start. Pulled trouble codes 23 which in my book is MAT sensor & 53 which shows battery voltage of more than 17.1 volts for 2 seconds. I did take the EGR off & clean it & replaced the CTS. After it dies & I restart the engine will idle really high, but that may be from unhooking the battery to clear codes. I have also checked for vacuum leaks & didn't find any. So I was wondering if it could possibly be the alternator? I had one go out about 6 yrs ago, but it acted more erratic than that. There doesn't seem to be a problem with any lights or anything else electrical except for the rpm gauge being higher than normal, which I had posted sometime ago & advice was the wire may be getting too hot. Any suggestions would be greatly appreciated. BYW I love this forum thanks to everyone!!!

[richtazz]

The ECM controls the voltage regulator, so it could be an ECM starting to go bad, or a bad ground, dirty connection, etc... Check actual voltage at the battery with the car running (Advance and Auto-Zone will do this for free if you don't have the equipment. It should be 14.8-16.2 volts if everything is as it should be. Any higher or lower and there is an electrical problem. Sometimes surges will cause voltage anomalies, but it's rare to trip a system over voltage code.

[TammyW]

We tried tapping on the ECM with the car running, it didn't die but it was cutting out & acted like it was going to die. I also looked at the service # & it has the same #s that others have said goes out. So what I'm wondering is could it also be a bad wire somewhere instead of the ECM?