O2 Sensors at 450mv
06-23-2012, 11:52 AM
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O2 Sensors at 450mv Here's the deal..
Started up the car (2001 Trans Am) and it is running like crap, almost as if the O2 sensors are swapped to opposite banks. So I plugged in the scanner to see what was going on. The O2 sensors for Bank1 and Bank2 are hovering around 450mv. Checked the Fuel Status on HPTuners and it says Open Loop, so I'm assuming the PCM isn't switching to Closed Loop even if all the conditions are met(ECT, IAT, ETC..) because it is not seeing the reading from the O2s.
I tried swapping O2 sensor side to side, I even plugged in another rear O2 sensor from the rear of my Corvette. Still seeing 450mv. Checked my grounds, they are good. Checked voltage and I have IGN(12V) at the sensor. Checked the High/Low continuity at the sensor plug and PCM plug and the continuity is good.
I don't know what to check next to find my problem. Any ideas?
Started up the car (2001 Trans Am) and it is running like crap, almost as if the O2 sensors are swapped to opposite banks. So I plugged in the scanner to see what was going on. The O2 sensors for Bank1 and Bank2 are hovering around 450mv. Checked the Fuel Status on HPTuners and it says Open Loop, so I'm assuming the PCM isn't switching to Closed Loop even if all the conditions are met(ECT, IAT, ETC..) because it is not seeing the reading from the O2s.
I tried swapping O2 sensor side to side, I even plugged in another rear O2 sensor from the rear of my Corvette. Still seeing 450mv. Checked my grounds, they are good. Checked voltage and I have IGN(12V) at the sensor. Checked the High/Low continuity at the sensor plug and PCM plug and the continuity is good.
I don't know what to check next to find my problem. Any ideas?
06-23-2012, 02:27 PM
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When the O2s are faulted out the PCM will force
450mV on them. Do you have O2 codes active,
maybe turned off with "no light" rather than "no
error reported"?
O2 sensor faults will inhibit open loop operation.
450mV on them. Do you have O2 codes active,
maybe turned off with "no light" rather than "no
error reported"?
O2 sensor faults will inhibit open loop operation.
06-24-2012, 05:49 PM
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Ok, I went and logged once idling, then after with just the ignition on. I am getting no codes and all O2 sensor codes are set to 0-MIL on first error.
The logs are attached..
The logs are attached..
06-25-2012, 04:51 PM
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Were stuck at 450mv before and swayed with the lope, don't know what changed.
No codes are set and I cleared codes.
I forced closed loop, bank 1 trims max adding fuel and bank2 trims max reducing fuel and eventually the car does not want to idle. I tried swapping sides O2 sensors side to side, swapping the harness to the opposite bank and it still wants to do the same thing.
I just ordered an AEM Eugo and will just tune the car OL SD and quit pissing around with these stock narrowbands.
No codes are set and I cleared codes.
I forced closed loop, bank 1 trims max adding fuel and bank2 trims max reducing fuel and eventually the car does not want to idle. I tried swapping sides O2 sensors side to side, swapping the harness to the opposite bank and it still wants to do the same thing.
I just ordered an AEM Eugo and will just tune the car OL SD and quit pissing around with these stock narrowbands.
