I have just recently installed the new Thermal Shield plate above the exhaust pipes to reduce the heat in my 98 Convertible. I only removed the back 2 oxygen sensor behind the catalytic converters for this process. Since this installation I am getting the "Check Engine" light with codes telling me that 3 of the 4 oxygen sensors are failing or not functioning properly. Also, I get a occassional "Reduce Engine Power" with the code of a failed or malfunction APP sensor. Im having a hard time believing that all 3 of these oxygen sensors have all failed at the same time........... Could be another famous ground issue with the PCM? I do not wish to replace all these oxygen sensors plus the APP sensor and find out that these are still OK. Does anybody have a feel of whats happening here or have had simular experiences?? I would appreciate any suggestions or advice on this subject........
Oh, and 2 of the oxygen sensors are the front 2 sensors which were not touched during this plate installation.....does not make sense......
Thanks again for any ideas..........
Andy

 

Check Splice Pack 122 and Ground G105. All of the O2 sensors are grounded through that splice pack and ground location. You may have disturbed the splice pack when you moved the rear sensors. It could have corroded or loose pins that are no longer making proper contact. The TAC module gets its ground at G106 which is located on the other side of the engine from G105. Maybe while you were under the car you disturbed these ground locations.

G105
Engine harness, LH side bottom of engine, ground for SP122 (CKT 150)
G106
Engine harness, RH side of the engine, above the starter (CKT 451)


Bill

 

Thanks Bill.............Ill check these for sure.........thanks again...

Andy