P0131
P0131-O2 SENSOR 1/1 CIRCUIT LOWP0131-O2 Sensor 1/1 Circuit Low:
WHEN MONITORED
Engine running for less than 30 seconds and the O2 Sensor Heater Temperature is less than 251° C (484° F) with battery voltage greater 10.4 volts.
SET CONDITION
The oxygen sensor signal voltage is below 2.5196 volts for 6 seconds after starting engine. Two Trip Fault. Three good trips to turn off the MIL.
POSSIBLE CAUSES
- (K902) O2 return upstream circuit shorted to ground
- (K41) O2 1/1 signal circuit shorted to ground
- (K41) O2 1/1 signal circuit shorted to the (K902) O2 return upstream circuit
- (K41) O2 1/1 signal circuit shorted to the (Z42) O2 1/1 heater ground circuit
- O2 sensor
- PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. O2 SENSOR BELOW 2.52 VOLTS
Start the engine.
Allow the engine to reach normal operating temperature.
With a scan tool, read the 1/1 O2 Sensor voltage.
Q: Is the voltage below 2.52 volts?
YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Component Tests and General Diagnostics
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
2. (K41) O2 SENSOR 1/1 SIGNAL CIRCUIT
Turn the ignition off.
Disconnect the 1/1 O2 Sensor harness connector.
Ignition on, engine not running.
With a scan tool, monitor the O2 Sensor voltage.
Q: Is the 1/1 O2 Sensor voltage above 4.8 volts?
YES: Go To 3
NO: Go To 5
3. O2 SENSOR
Measure the voltage on the (K902) O2 Return Upstream circuit in the O2 Sensor harness connector.
Q: Is the voltage at 2.5 volts?
YES: Replace the O2 Sensor. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 4
4. (K902) O2 RETURN UPSTREAM CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C1 PCM harness connector.
Measure the resistance between ground and the (K902) O2 Return Upstream circuit in the O2 Sensor harness connector.
Q: Is the resistance below 100 ohms?
YES: Repair the short to ground in the (K902) O2 Return Upstream circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 8
5. (K41) O2 SENSOR 1/1 SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C1 and C2 PCM harness connectors.
Measure the resistance between ground and the (K41) O2 Sensor 1/1 Signal circuit in the O2 Sensor harness connector.
Q: Is the resistance below 100 ohms?
YES: Repair the short to ground in the (K41) O2 Sensor 1/1 Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 6
6. (K41) O2 SENSOR 1/1 SIGNAL CIRCUIT SHORTED TO THE (K902) O2 RETURN UPSTREAM CIRCUIT
Measure the resistance between the (K41) O2 Sensor 1/1 Signal circuit and the (K902) O2 Return Upstream circuit in the O2 Sensor harness connector.
Q: Is the resistance below 100 ohms?
YES: Repair the short between the (K902) O2 Return Upstream circuit and the (K41) O2 Sensor 1/1 Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 7
7. (K41) O2 SENSOR 1/1 SIGNAL CIRCUIT SHORTED TO THE (Z42) O2 1/1 HEATER GROUND CIRCUIT
Measure the resistance between the (K41) O2 Sensor 1/1 Signal circuit and the (Z42) O2 1/1 Heater ground circuit in the O2 Sensor harness connector.
Q: Is the resistance below 100 ohms?
YES: Repair the short between the (Z42) O2 1/1 Heater ground circuit and the (K41) O2 Sensor 1/1 Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 8
8. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Q: Were there any problems found?
YES: Repair as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Replace and program the Powertrain Control Module. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test