Just curious

[Ron Walker]

The MAF was replaced (due to code (E034) and then I got a code for the Cam Sensor (E041). Replaced both which were of no help. I then got a code for the Ignition System (E042) and after checking and finding that two cylinders were not getting spark, I then replaced the Ignition coil and ignition control module. The car now runs great (at least for the 25-30 miles that I've driven since). Turns out, I suspect, that the ICM was probably the original culprit all along in spite of the E034 and E041 codes.  Funny thing is that the codes popped up one at a time and not all at once. Had the E042 code shown up first, a replacement ICM and coil pack may have cured the poor performance right off the bat. As it is, I spent way too much on trouble shooting, especially with the replacement MAF (and also the catalytic converter) before checking the ignition coils. I'd suggest that anyone encountering extremely poor performance start off by testing the ignition coil and ICM. 

BUT, the Service Engine light still stays on. I've tried disconnecting the battery to hope for a re-set, but no luck. Anybody else have a cure for that problem?

[2seater]

If I understand what is happening, Check Engine Light but no codes are recorded? Have you tried the code reset in diagnostics, for both ECM and BCM?

[Padgett]

Have to know the codes (if light is on and not in diagnostics something must be current).

[DAVES89]

Is it the Service engine light in the speedo lighting up or the service engine warning on the CRT that you see? 

[Ron Walker]

First, the "Service Engine Soon" in the dash is lit up. Then, the CRT shows a warning that an Engine Control Problem has been detected. If I go to the CRT and choose Status/Diagnostic, everything is OK except the Engine Monitor which then takes me to the Cruise Control System. The warning says that the Cruise has been disengaged.

 

I've had an inoperable Cruise Control for several years (Code B671) and until recently, I never got an "Service Engine Soon" light up in the dash - I would, however, from time to time, get the CRT warning, but I would routinely hit the "return" key and the warning would disappear, sometimes for months before getting another such warning.  

 

Moments ago I rechecked the diagnostics on the CRT - got a current and history E041 - reset the ECM Codes and they cleared. Got a current B671 code, got to the reset, but the CRT says that the "BCM Codes Not Clear." I tried resetting the BCM codes a couple times, and same thing - "BCM Codes Not Clear."

 

Bottom line, "Service Engine Soon" light in the dash still lit up. 

 

[Padgett]

B671 - cruise, server position servo circuit. First I'd just R&R the connector. If doesn't fix is either wiring or the cruise servo itself. Millions in GM cars of the period.