DTC P0137: 1/2 O2 Sensor Shorted To Ground: Testing
NOTE:
1/2 HO2S may also be referred to as a downstream oxygen sensor. 1/2 HO2S is located behind right catalytic converter.
- Start engine and let it idle. Using scan tool, read 1/2 HO2S voltage. If voltage is less than .16 volt, go to next step. If voltage is .16 volt or more, go to step 7 .
- With engine running, Disconnect 1/2 HO2S harness connector. Using scan tool, read 1/2 HO2S voltage. If voltage is .16 volt or less, go to next step. If voltage is more than .16 volt, replace 1/2 HO2S.
- Turn ignition off. Disconnect PCM harness connectors. See Figure . Measure resistance between ground and signal circuit (Tan/White wire) at 1/2 HO2S harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Tan/White wire.
- Measure resistance between signal circuit (Tan/White wire) and sensor ground circuit (Black/Light Blue wire) at 1/2 HO2S harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short between signal circuit and sensor ground circuit.
- Measure resistance between signal circuit (Tan/White wire) and heater ground circuit (Black wire) at 1/2 HO2S harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short between signal circuit and heater ground circuit.
- If no other possible causes are remaining, PCM is assumed to be defective. Replace PCM.
- Conditions that set DTC are not present at this time. Perform the following to help identify intermittent condition:
- With engine running at normal operating temperature, wiggle wiring harness between 1/2 HO2S and PCM while monitoring 1/2 HO2S voltage on scan tool. If voltage changes or DTC sets while wiggling wiring harness, repair connectors or wiring harness where wiggling caused voltage to change or DTC to set.
- Review freeze frame information on scan tool. Duplicate conditions present when DTC was set.
- Refer to any technical service bulletins that may apply.
- Visually inspect related wiring harness. Check for chafed, pierced, pinched or partially broken wires.
- Visually inspect related wiring harness connectors. Check for broken, bent, pushed out or corroded terminals.
If a problem is found, repair as necessary. If no problems are found, test is complete.