DTC Troubleshooting: P0131 (1-1)
|DTC P0131 (1-1):||HO2S Circuit Low Voltage|
|1.||Reset the ECM/PCM.|
|2.||Start the engine. Hold the engine at 3,000 rpm (min-1) with no load (in Park or neutral) until the radiator fan comes on.|
|3.||Check the HO2S output voltage with the scan tool during acceleration using wide open throttle.|
Does the voltage stay at 0.5 V or less?
YES - Go to 4.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the HO2S and at the ECM/ PCM.n
|4.||Check the fuel pressure.|
Is it normal?
YES - Go to 5.
NO - Repair the fuel supply system.n
|5.||Turn the ignition switch OFF.|
|6.||Disconnect the HO2S 4P connector.|
|7.||Turn the ignition switch ON (II).|
|8.||Check the HO2S output voltage with the scan tool.|
Does it stay at 0.5 V or less?
YES - Go to 9.
NO - Replace the HO2S.n
|9.||Turn the ignition switch OFF.|
|10.||Disconnect ECM/PCM connector A (31P).|
|11.||Check for continuity between the HO2S 4P connector terminal No. 1 and body ground.|
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (A6) and the HO2S.n
NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.n