My '97 has a persistent Poor Performance message that always shows. My mechanic has confirmed that the car runs fine and has no clue as to how to clear it as his scanner shows no issues. I also get a P1000 code (incomplete test) that never clears. I’ve had the ECU module rebuilt and tested twice since with no errors on the test bench. The frustrating thing is that the car runs great with no issues. Anyone had this problem?
I’ve not had the problem but it seams a standard tactic with such problems is to disconnect the battery for 15 minutes and then reconnect it and see if the problem has disappeared.
No luck, my mechanic tried that and everything else he could think of. My mechanic even swapped the throttle body with a known good one as a test to see if that was the issue. The maddening thing is that the car runs great. It even passed my State’s emissions test with zero issues.
You probably need to interrogate EVERY module on the CAN bus to get DTCs.
The modules on that network can cause the others to react to a problem.
Just looking at just the ECM might not tell the story?
1 Like
If you find a module down & out, replace it with a proper NEW one. DO NOT use an old one or USED from E-Bay or anyone else.
Many modules for these cars are NLA. Without a good-used, the car is SCRAP!
The 4.0 liter cars have easily replaced used modules. The only module that needs configuration is the ECM if the car has RFID and a key transponder.(Needs IMMOBILIZATION SETUP every time the ECM is swapped or installed into a different car)
All the other modules just need the VCATS to match.
The 4.2 liter cars are a whole different story!
The VID block is complicated when it comes to swapping/replacing modules.
A corrupted VID block can damage the entire network.
A NEW module and configuration is the best way to go if a NEW module is available for the VID block cars. (4.2 liter)
1 Like