My tuner turned off my rear o2 sensors but I know power is still sent to them from the computer. Don't ask me about that short lol. Yesterday I unplugged the o2 sensor and zip tied the wire harness up, and I got two codes p1132 & p1152. Both of these codes refer to rear o2 sensors. Plugged them back in with the pig tail cut from the sensor and no more codes and car runs great? Can someone explain how that all works?
Turning off Rear o2 Sensors in Tune
- Thread starter COBRA97SVT
- Start date
"DTCs P1131, P1151, P1132 AND P1152: UPSTREAM HO2S(S) NOT SWITCHING. DTCs P1130 AND P1150: FUEL SYSTEM NOT SWITCHING AT FUEL TRIM (RICH OR LEAN)
Diagnostic Trouble Codes (DTCs) P1131 bank 1 (Cylinder 1) and P1151 bank 2 indicate the fuel/air ratio is correcting rich for an overly lean condition. The HO2S voltage is less than 0.45 volt. DTCs P1132 bank 1 (Cylinder 1) and P1152 bank 2 indicate the fuel/air ratio is correcting lean for an overly rich condition. The HO2S voltage is greater than 0.45 volt.
DTCs P1130 and P1150 indicate the fuel control system has reached maximum compensation for a lean or rich condition and the HO2S is not switching.
DTC/HO2S Reference List
HO2S-11 = DTCs P1131, P1132 and P1130
HO2S-21 = DTCs P1151, P1152 and P1150
Possible causes:
Fuel system
Excessive fuel pressure.
Leaking fuel injector(s).
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel.
Contaminated fuel injector(s)
Induction system
Air leaks after the MAF.
Vacuum leaks (vacuum lines and gaskets).
Restricted air inlet.
PCV system.
Fuel purge system.
Improperly seated engine oil dipstick.
EGR System
Leaking gasket.
Stuck open EGR valve.
Leaking diaphragm.
Base engine
Oil overfill.
Cam timing.
Cylinder compression.
Exhaust leaks before or near the HO2Ss.
Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check for vacuum leaks. "
These codes refer to the upstream sensors. So.... something is amiss here.
Exactly what your tuner did for the rear 02s will have to be answered by him. I don't know if they tell the PCM to ignore all downstream voltages, I don't know if they just tell the PCM to stop running catalyst efficiency monitors, etc. The PCM still checks the heater circuits too so perhaps they just pull the fuse and tell the PCM to ignore heater circuit checks as well.... I know PCM parameters but I don't know what options these tuners have or furthermore what options the tuners chose.
If you have P1132 and P1152 and ONLY these codes I can give you a pretty good rundown of rich contributor diagnostics....which should be "fun" with said "tune".
Do you have the ability to datalog? That would sure help diagnose a "rich" condition
Are you POSITIVE there is relativity between your codes and whatever you were doing with disconnecting the rear sensors?
Are you SURE it was the rear sensors you disconnected?
You cut the pigtail from the rear sensors?
Perhaps I don't understand what you said about unplugging sensors, tieing them up and plugging them back in.
Either way these codes mean the upstream 02 signal as pegged above .5v no matter how much fuel the PCM pulled from the fuel trims. Should have put you in Open Loop Fault for a moment too
Diagnostic Trouble Codes (DTCs) P1131 bank 1 (Cylinder 1) and P1151 bank 2 indicate the fuel/air ratio is correcting rich for an overly lean condition. The HO2S voltage is less than 0.45 volt. DTCs P1132 bank 1 (Cylinder 1) and P1152 bank 2 indicate the fuel/air ratio is correcting lean for an overly rich condition. The HO2S voltage is greater than 0.45 volt.
DTCs P1130 and P1150 indicate the fuel control system has reached maximum compensation for a lean or rich condition and the HO2S is not switching.
DTC/HO2S Reference List
HO2S-11 = DTCs P1131, P1132 and P1130
HO2S-21 = DTCs P1151, P1152 and P1150
Possible causes:
Fuel system
Excessive fuel pressure.
Leaking fuel injector(s).
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel.
Contaminated fuel injector(s)
Induction system
Air leaks after the MAF.
Vacuum leaks (vacuum lines and gaskets).
Restricted air inlet.
PCV system.
Fuel purge system.
Improperly seated engine oil dipstick.
EGR System
Leaking gasket.
Stuck open EGR valve.
Leaking diaphragm.
Base engine
Oil overfill.
Cam timing.
Cylinder compression.
Exhaust leaks before or near the HO2Ss.
Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check for vacuum leaks. "
These codes refer to the upstream sensors. So.... something is amiss here.
Exactly what your tuner did for the rear 02s will have to be answered by him. I don't know if they tell the PCM to ignore all downstream voltages, I don't know if they just tell the PCM to stop running catalyst efficiency monitors, etc. The PCM still checks the heater circuits too so perhaps they just pull the fuse and tell the PCM to ignore heater circuit checks as well.... I know PCM parameters but I don't know what options these tuners have or furthermore what options the tuners chose.
If you have P1132 and P1152 and ONLY these codes I can give you a pretty good rundown of rich contributor diagnostics....which should be "fun" with said "tune".
Do you have the ability to datalog? That would sure help diagnose a "rich" condition
Are you POSITIVE there is relativity between your codes and whatever you were doing with disconnecting the rear sensors?
Are you SURE it was the rear sensors you disconnected?
You cut the pigtail from the rear sensors?
Perhaps I don't understand what you said about unplugging sensors, tieing them up and plugging them back in.
Either way these codes mean the upstream 02 signal as pegged above .5v no matter how much fuel the PCM pulled from the fuel trims. Should have put you in Open Loop Fault for a moment too
Wow thanks for the info! There are too many variables I guess. The car sat for a year and I never drained the tank like I should have. I added octane. Booster thinking that may help. I have also replaced a bad rubber vacuum line cap. No. Codes the last couple of days.
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