Heavyopp
NAXJA Forum User
- Location
- Middlesex, NJ
Need some help -- been reading for days looking for answers
2000 Cherokee sport -- 225,000 miles bought it 2 months ago for $200 -- barely any rust -- zero rot anywhere
Here's what I know -- Right now throwing codes P0123, P0122, P1694 -- barely idles, runs rough off idle -- California emissions -- glowing red exhaust pipe for 6 inches after rear pre cat only also red at bottom of pre cat housing but only rear pre cat
In diagnosing a bad TPS i get some weird voltage readings -- 5.2 volts on voltage input pin -- Ground pin seems good also but I get 4.32 volts at the TPS output pin -- this is with the TPS UNPLUGGED -- all these readings are at the wire connector -- 4.32 volts coming from the PCM for the TPS signal pin -- shouldn't it be 0 volts
In searching and reading here I've tried a few things on the few threads I can find with similar problems -- I've pulled the horn relay to eliminate a clock spring issue -- I've also gone thru and cleaned up all the grounds I can find
I also checked the PCM -- Unplugged wire harness "A" and tested the pins on the PCM
pin 17 is 5 volt output to sensors -- I get 7 volts at pin 17 with harness "A" unplugged
Pin 23 is input from TPS -- I get 6 volts at this pin when harness is unplugged -- Shouldn't it be 0 and waiting for input from TPS?
Once I plug in harness "A" and test at TPS connector my voltages drop to 5.2 for the 5 volt input and 4.32 for the middle wire -- the one for TPS output
I'm lost -- Do I have a faulty PCM? -- By unplugging the wiring harness from PCM and still getting voltage at pin 23 I have eliminated a problem in the wiring harness - correct?
Thoughts? Should I be looking for a PCM, it's a 635 AG?
Jer
2000 Cherokee sport -- 225,000 miles bought it 2 months ago for $200 -- barely any rust -- zero rot anywhere
Here's what I know -- Right now throwing codes P0123, P0122, P1694 -- barely idles, runs rough off idle -- California emissions -- glowing red exhaust pipe for 6 inches after rear pre cat only also red at bottom of pre cat housing but only rear pre cat
In diagnosing a bad TPS i get some weird voltage readings -- 5.2 volts on voltage input pin -- Ground pin seems good also but I get 4.32 volts at the TPS output pin -- this is with the TPS UNPLUGGED -- all these readings are at the wire connector -- 4.32 volts coming from the PCM for the TPS signal pin -- shouldn't it be 0 volts
In searching and reading here I've tried a few things on the few threads I can find with similar problems -- I've pulled the horn relay to eliminate a clock spring issue -- I've also gone thru and cleaned up all the grounds I can find
I also checked the PCM -- Unplugged wire harness "A" and tested the pins on the PCM
pin 17 is 5 volt output to sensors -- I get 7 volts at pin 17 with harness "A" unplugged
Pin 23 is input from TPS -- I get 6 volts at this pin when harness is unplugged -- Shouldn't it be 0 and waiting for input from TPS?
Once I plug in harness "A" and test at TPS connector my voltages drop to 5.2 for the 5 volt input and 4.32 for the middle wire -- the one for TPS output
I'm lost -- Do I have a faulty PCM? -- By unplugging the wiring harness from PCM and still getting voltage at pin 23 I have eliminated a problem in the wiring harness - correct?
Thoughts? Should I be looking for a PCM, it's a 635 AG?
Jer