O2 sensor circuit

de 203996

New Member
My truck is a 1999 tocoma regular cab 2.4 engine ..had a code PO 135.. replaced upstream sensor with Denso...code came back..checked at connector..had 12v on plus side and no grd from computor key on.The wire from grd at o2 sensor is purple with black stripe...think at ECU a wire that color is at E8 # 2 wire but no continuity from ecu to sensor both unpluged..am i right for wire from ecu or did i miss it..looking at info for differant models this wire should be a straight shot.can anybody verify the ecu pin # for heated grd wire for O2 sensor..dealing with #1 and 2 wires at sensor
 
My truck is a 1999 tocoma regular cab 2.4 engine ..had a code PO 135.. replaced upstream sensor with Denso...code came back..checked at connector..had 12v on plus side and no grd from computor key on.The wire from grd at o2 sensor is purple with black stripe...think at ECU a wire that color is at E8 # 2 wire but no continuity from ecu to sensor both unpluged..am i right for wire from ecu or did i miss it..looking at info for differant models this wire should be a straight shot.can anybody verify the ecu pin # for heated grd wire for O2 sensor..dealing with #1 and 2 wires at sensor
Found my problem..........
 
The suspense is killing me.....
Was right on the color of # 2 pin at ECU... jumpered that wire to Ox senser and then got a PO 125 code quick......took jumper back off and got PO125 and PO 135...replaced ECT sensor which helped nothing...traced wiring as far as i could in both directions..checked O2 sensor i bought and it was correct.....then i found it....light pull of wires on top of trans gave me all 4 wires going to front O2 sensor in my hand..took connector to auto trans off and harness came out far enough to see Mr squrrel's eating through split loom ,tape and wires through copper in a 1/4 area
 
Was right on the color of # 2 pin at ECU... jumpered that wire to Ox senser and then got a PO 125 code quick......took jumper back off and got PO125 and PO 135...replaced ECT sensor which helped nothing...traced wiring as far as i could in both directions..checked O2 sensor i bought and it was correct.....then i found it....light pull of wires on top of trans gave me all 4 wires going to front O2 sensor in my hand..took connector to auto trans off and harness came out far enough to see Mr squrrel's eating through split loom ,tape and wires through copper in a 1/4 area
Damn you mr squirrel! Glad you figured it out. Sounds like a PITA.
 
Was right on the color of # 2 pin at ECU... jumpered that wire to Ox senser and then got a PO 125 code quick......took jumper back off and got PO125 and PO 135...replaced ECT sensor which helped nothing...traced wiring as far as i could in both directions..checked O2 sensor i bought and it was correct.....then i found it....light pull of wires on top of trans gave me all 4 wires going to front O2 sensor in my hand..took connector to auto trans off and harness came out far enough to see Mr squrrel's eating through split loom ,tape and wires through copper in a 1/4 area

Wow. That was some work.
 
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