possible oxygen sensor malfunction - '96 ZJ
well, ive been having an issue with akward running conditions, ive had it become hard to start once or twice, and the check engine light is always on now.. so i had my cousin check the diagnostics... and this is what came up on three readings... to me these sound like an oxygen sensor issue, and upon inspection of the undercarriage of the vehicle, it appears as if the wire leading to the oxygen sensor is partially melted, could this wire, if not the sensor be responsible for these readings?... i copied this all word for word from the printed tickets i received from autozone
READING 1
Definition: Governor pressure sensor offset voltage too high or low
Explanation: ECM detected the offset voltage was out of spec for more than 3 seconds
Probable Causes
1: Internal transmission failure
2: Open or shorted circuit condition
READING 2
Definition: Governor pressure above 3 PSI at 0 MPH
Explanation: EMC detected vehicle not moving yet governor pressure is above 0 PSI
Probable Causes
1: Internal transmission failure
2: Open or shorted circuit condition
READING 3
Definition: Circuit condition (heated oxygen sensor bank 1 senor 2
Explanation: The powertrain control module uses the oxygen sensor to calculate the air/fuel ratio in the exhaust
Probable Causes
1: Oxygen Sensor Defective
2: Fuel system running very rich or lean - check other codes first
3: Engine misfire condition - repair
4: Fuel pressure very high or low - fuel pump or pressure regulator
READING 1
Definition: Governor pressure sensor offset voltage too high or low
Explanation: ECM detected the offset voltage was out of spec for more than 3 seconds
Probable Causes
1: Internal transmission failure
2: Open or shorted circuit condition
READING 2
Definition: Governor pressure above 3 PSI at 0 MPH
Explanation: EMC detected vehicle not moving yet governor pressure is above 0 PSI
Probable Causes
1: Internal transmission failure
2: Open or shorted circuit condition
READING 3
Definition: Circuit condition (heated oxygen sensor bank 1 senor 2
Explanation: The powertrain control module uses the oxygen sensor to calculate the air/fuel ratio in the exhaust
Probable Causes
1: Oxygen Sensor Defective
2: Fuel system running very rich or lean - check other codes first
3: Engine misfire condition - repair
4: Fuel pressure very high or low - fuel pump or pressure regulator
well, tomorrow ill be replacing the hinge pins and bushings on the driver side door.. i will crawl underneath and get a better look at the wire to see if its melted through... could this wire cause both a poor fuel mixture as well as the other issues stated in the readings?.. two tickets suggested a shorted wire, one suggested a bad oxygen sensor
Just That Awesome
Joined: Oct 2010
Posts: 1,673
Likes: 0
From: Hannibal, MO
Year: 1993
Model: Grand Cherokee
Engine: 4.0
Again, a shorted wire will kill the signal between the 02 sensor and the computer. The o2 sensor is responsible for mixture so yea it would affect it
Senior Member
Joined: Dec 2010
Posts: 698
Likes: 2
From: Norman, OK
Year: 95
Model: Grand Cherokee
Engine: 4.0
Like mentioned above, when you have shorted wiring to sensors it can mess with other sensors or electronic components. Keep in mind though, the gov pressure sensor and solenoid are also notorius for failures too.
Either of these conditions should not directly affect starting issues, but either one can turn the check engine light on. You will probably have trans shifting issues associated with the gov press sensor concern, usually 3rd gear starts, or very quick upshifts/shuttle shifts.
Either of these conditions should not directly affect starting issues, but either one can turn the check engine light on. You will probably have trans shifting issues associated with the gov press sensor concern, usually 3rd gear starts, or very quick upshifts/shuttle shifts.
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Just That Awesome
Joined: Oct 2010
Posts: 1,673
Likes: 0
From: Hannibal, MO
Year: 1993
Model: Grand Cherokee
Engine: 4.0
well i dont have the cash to replace the O2 sensor, so i dont intend to unless absolutely neccessary... im going to replace the wire first, see if that fixes the issue.. have another diagnostics ran on it afterwards, and if thats an issue ill remove it and have it tested i guess
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