O2 sensor CEL

[supersupramk3]

CEL for o2 is still on after putting a new one in. With my original harness im thinking there might be a break in the wire somewhere from the o2 to the ecu. Is there a way to trace or check the continuity of the wires from the plug to the ecu pins/harness??? I know there are three wires @ o2 and I believe only one ends up at the ECU. SMOG coming up soon and need to pass or else will have to be parked (its gonna suck not being able to spool up). THX.

 

[hvyman]

did you reset the codes?

 

[supersupramk3]

did you reset the codes?

Yep, i pulled the EFI fuse to reset the code. The CEL comes on immediately after starting the car.

 

[Hmong_1G]

New bosch unit? Bosch is crap. Chance of getting one that works properly is very very low.

 

[Zumtizzle]

^Bosch is the inventor of the O2 sensor.


So they must know something.....


Can you check wiring?

 

[supersupramk3]

New bosch unit? Bosch is crap. Chance of getting one that works properly is very very low.

Nope this one is not a Bosch...its a Denso! Any inputs on how to check the continuity of the wires, and which one????

 

[radiod]

Some troubleshooting from the TSRM for the O2 sensor:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=119

Start by checking wiring and resistances. Make sure the pigtail wasn't getting too close to the exhaust and burning away. Check the clip and connections. If those all check out ok, I'd start on that flow chart and measuring the heater resistance.

 

[hvyman]

what code are you getting. and you need to pull the fuse for at least 30 sec(if you already didn't know)

 

[supersupramk3]

what code are you getting. and you need to pull the fuse for at least 30 sec(if you already didn't know)

Gettin a code 21, and yes have pulled the fuse for 30 sec or more. I have tried that test from the tsrm....Im not sure if im doin it correctly or not but basically it leads to either a bad ecu or bad o2. I just need to check the conituity throughout the wires towards the ECU. Anybody else got a clue.

 

[hvyman]

disconnect the o2 sensor and the ecu and check the continuity threw the wires.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=50

if you get none theirs a open in the circuit somewhere.

 

[supersupramk3]

disconnect the o2 sensor and the ecu and check the continuity threw the wires.

Thx....ill give it a shot!:: angry ::
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=50

if you get none theirs a open in the circuit somewhere.