My '97 Sable is displaying codes P0420 and P0430. I would like to determine if I have a problem with the O2 sensors, the convertors or a wiring problem.
I tried to use the diagnostic procedure mentioned in the Haynes manual. Basically, it said to connect a multimeter to a good ground, backprobe the O2 sensor connector and turn the ignition to the ON position. It said that the reading should be .4 volts or 400 millivolts. I am not getting this reading or anything close to it. My questions are these:
Which wire should I be probing? What color is it coming out of the wiring harness?
Could I have a wiring problem and if so could it cause these codes to be displayed? There seems to be one common wire running between all 4 O2 sensors, some other sensors and the PCM. How can I effectively test this wire for proper operation?
Does anyone know how to measure the O2 sensor related terminals at the PCM for proper signal/voltage? I saw a wiring diagram in the back of the Haynes manual which points out the various O2 related wires , but doesn't tell you how to test the PCM for proper output/input?
Any and all assistance would be appreciated.
Thanks.
Frank
I tried to use the diagnostic procedure mentioned in the Haynes manual. Basically, it said to connect a multimeter to a good ground, backprobe the O2 sensor connector and turn the ignition to the ON position. It said that the reading should be .4 volts or 400 millivolts. I am not getting this reading or anything close to it. My questions are these:
Which wire should I be probing? What color is it coming out of the wiring harness?
Could I have a wiring problem and if so could it cause these codes to be displayed? There seems to be one common wire running between all 4 O2 sensors, some other sensors and the PCM. How can I effectively test this wire for proper operation?
Does anyone know how to measure the O2 sensor related terminals at the PCM for proper signal/voltage? I saw a wiring diagram in the back of the Haynes manual which points out the various O2 related wires , but doesn't tell you how to test the PCM for proper output/input?
Any and all assistance would be appreciated.
Thanks.
Frank
Jul 24, 2006 at 9:35 AM