|DTC P0131 (1-1):||Primary HO2S(Sensor 1) 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 primary HO2S (Sensor 1) 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 primary HO2S (Sensor 1) 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 primary HO2S (Sensor 1) 4P connector.|
|7.||Turn the ignition switch ON (II).|
|8.||Check the primary HO2S (Sensor 1) output voltage with the scan tool.|
Does it stay at 0.5 V or less?
YES - Go to 9.
NO - Replace the primary HO2S (Sensor 1).n
|9.||Turn the ignition switch OFF.|
|10.||Disconnect the negative cable from the battery.|
|11.||Disconnect ECM/PCM connector A (31P).|
|12.||Check for continuity between the primary HO2S (Sensor 1) 4P connector terminal No. 1 and body ground.|
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (A6) and the primary HO2S (Sensor 1).n
NO - Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original ECM/ PCM.n