P0137
DTC P0137: Secondary HO(2)S (Sensor 2) Circuit Low Voltage1. Reset the PCM.
2. Start the engine. Hold the engine at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on.
3. Check the secondary HO(2)S (Sensor 2) output voltage at 3,000 rpm with the scan tool.
Does the voltage stay at 0.3 V or less?
YES - Go to step 4.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the secondary HO(2)S (Sensor 2) and the PCM.
4. Turn the ignition switch OFF.
5. Disconnect the secondary HO(2)S (Sensor 2) 4P connector.
6. Turn the ignition switch ON (II).
7. Check the secondary HO(2)S (Sensor 2) output voltage with the scan tool.
Does the voltage stay at 0.3 V or less?
YES - Go to step 8.
NO - Replace the secondary HO(2)S (Sensor 2).
8. Turn the ignition switch OFF.
9. Disconnect the negative battery cable from the battery.
10. Disconnect PCM connector A (32P).
11. Check for continuity between secondary HO(2)S (Sensor 2) 4P connector terminal No.2 and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (A1) and the secondary HO(2)S (Sensor 2).
NO - Substitute a known-good PCM and recheck. If the symptom/indication goes away, replace the original PCM.