P0138
DTC P0138: Secondary HO(2)S (Sensor 2) Circuit High 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 1.0 V or more?
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. Connect secondary HO(2)S (Sensor 2) 4P connector terminals No.1 and No.2 with a jumper wire.
7. Turn the ignition switch ON (II).
8. Check the secondary HO(2)S (Sensor 2) output voltage with the scan tool.
Is there 1.0 V or more?
YES - Go to step 9.
NO - Replace the secondary HO(2)S (Sensor 2).
9. Turn the ignition switch OFF.
10. Connect PCM connector terminals (A1 and C18) with a jumper wire.
11. Turn the ignition switch ON (II).
12. Check the secondary HO(2)S (Sensor 2) output voltage with the scan tool.
Is there 1.0 V or more?
YES - Substitute a known-good PCM and recheck. If the symptom/indication goes away, replace the original PCM.
NO - Repair open in the wire between the PCM (A1, C18) and the secondary HO(2)S (Sensor 2).