P0131
P0131 - O2 Sensor 1/1 Circuit Low
For wiring diagrams, refer to.
• When Monitored: With the engine running for less than 30 seconds, the 1/1 oxygen sensor heater temperature less than 251 °C (484 °F), and battery voltage greater than 10 volts.
• Set Condition: The PCM detects that the 1/1 oxygen sensor signal voltage is less than 2.5196 volts for 6 seconds after engine startup. One Trip Fault. Three good trips to turn off the MIL.
• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure
Test Step 1 - DTC is Active
• Turn the ignition ON.
• With a scan tool, select view DTCs. Record DTC and freeze frame information.
• Start the engine and allow it to idle for at least 60 seconds.
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
• With a scan tool, select view DTCs.
Is the status active for this DTC?
Yes
• Go to Test Step 2 => [ Test
Step 2 - O2S 1/1 Signal Circuit Voltage ]
No
• Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC
Test Step 2 - O2S 1/1 Signal Circuit Voltage
• Turn the ignition OFF.
• Disconnect the 1/1 oxygen sensor harness connector.
• Turn the ignition ON.
• With a scan tool, monitor the sensor voltage.
Is the voltage more than 4.8 volts?
Yes
• Go to Test Step 3 => [ Test
Step 3 - 1/1 Oxygen Sensor Return Circuit Voltage ]
No
• Go to Test Step 5 => [ Test
Step 5 - O2S 1/1 Signal Circuit Shorted to Ground ]
Test Step 3 - 1/1 Oxygen Sensor Return Circuit Voltage
• Measure the voltage on the O2S 1/1 return circuit in the harness connector.
Is the voltage between 2.475 and 2.525 volts?
Yes
• Go to Test Step 7 => [ Test
Step 7 - 1/1 oxygen sensor ]
No
• Go to Test Step 4 => [ Test
Step 4 - O2S 1/1 Return Circuit Shorted to Ground ]
Test Step 4 - O2S 1/1 Return Circuit Shorted to Ground
• Turn the ignition OFF.
• Disconnect the PCM harness connector.
• Measure the resistance between ground and the O2S 1/1 return circuit in the harness connector.
Is the resistance less than 100 ohms?
Yes
• Repair the O2S 1/1 return circuit for a short to ground.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 8 => [ Test
Step 8 - PCM ]
Test Step 5 - O2S 1/1 Signal Circuit Shorted to Ground
• Measure the resistance between ground and the O2S 1/1 signal circuit in the harness connector.
Is the resistance less than 100 ohms?
Yes
• Repair the O2S 1/1 signal circuit for a short to ground.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 6 => [ Test
Step 6 - O2S 1/1 Signal Circuit Shorted to O2S 1/1 Return Circuit ]
Test Step 6 - O2S 1/1 Signal Circuit Shorted to O2S 1/1 Return Circuit
• Measure the resistance between the O2S 1/1 signal circuit and the O2S 1/1 return circuit in the harness connector.
Is the resistance less than 100 ohms?
Yes
• Repair the short between the O2S 1/1 return circuit and the O2S 1/1 signal circuit.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 8 => [ Test
Step 8 - PCM ]
Test Step 7 - 1/1 oxygen sensor
• Turn the ignition OFF.
• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the 1/1 oxygen sensor and the PCM.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Replace the 1/1 oxygen sensor.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
Test Step 8 - PCM
• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the 1/1 oxygen sensor and the PCM.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related connectors.
• Refer to any technical service bulletins that may apply.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Replace and program the PCM.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test