Check engine light
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Check engine light
The check engine light on my 98 Explorer (v6,soc) came on recently. Code reader indicated faulty oxygen sensor (p135). Replaced same, cleared code but light came back on. Cleared code again, same thing. Further research on internet (Ford tsb's) added the following: disconnected harness, bent or corroded pins, exhaust leak, electrical short. Assuming the first two are not the cause, where would I begin to diagnose the leak or the short? Can anybody help? Thanks.
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First off did you replace the correct sensor... P0135, I believe is bank 1, sensor 1.. which is the sensor between the engine and the cat on the passenger side.
It also refers to the heater, and not the actual sensor (although the heater is BUILT into the sensor)... however a broken wire for the heater, pushed out pin at the connector, or faulty computer can be to blame as well.
It also refers to the heater, and not the actual sensor (although the heater is BUILT into the sensor)... however a broken wire for the heater, pushed out pin at the connector, or faulty computer can be to blame as well.
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Thanks for taking time to reply. I'm sure I got the correct sensor. Since it was new I'm assuming the pins and wiring inside are good. I'll double check the connection but as I recall the male and female ends only go together one way. By faulty computer, are you referring to the ecm? If so, wouldn't I get additional error codes stating same?
John
John
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The same code will come about if you have a vacuum leak. Why, because the O2 sensor reads that the bank is too lean, so everyone replaces the sensor and then has the same code. What happens is, because of the vacuum leak, more air gets into the cylinder, thus, the bank is lean and the sensor is reading correctly...
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No this code is for the heater circuit of the O2 sensor, not the "operational" circuit.
First check for power at both ends of the fuse in the power distribution box.. it's fuse #13... 15 amp mini fuse. If you have power there then unplug the connector for that O2 sensor and check for power at the Light Blue/Orange wire with key on, engine off (engine side connector, not O2 side).. you should get 12 volts. If you have voltage here then you have a defective O2 sensor, or a bad ECM.
If no power you'll have to trace that Light Blue/Orange wire all the way to Splice #142 "100mm from T/O for Connector #169"... Connector #169 is at the "Right hand (passenger) rear of engine".. I'm looking at the wire diagram and Power comes out of the fuse box to Splice #142.. which then splits into three wires.. one for each O2 sensor.
Sorry I can't give you more information.. this is the most detailed my source gets, but maybe it'll help.
Good luck.
First check for power at both ends of the fuse in the power distribution box.. it's fuse #13... 15 amp mini fuse. If you have power there then unplug the connector for that O2 sensor and check for power at the Light Blue/Orange wire with key on, engine off (engine side connector, not O2 side).. you should get 12 volts. If you have voltage here then you have a defective O2 sensor, or a bad ECM.
If no power you'll have to trace that Light Blue/Orange wire all the way to Splice #142 "100mm from T/O for Connector #169"... Connector #169 is at the "Right hand (passenger) rear of engine".. I'm looking at the wire diagram and Power comes out of the fuse box to Splice #142.. which then splits into three wires.. one for each O2 sensor.
Sorry I can't give you more information.. this is the most detailed my source gets, but maybe it'll help.
Good luck.
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