SULEV EX Model
DTC P0138: High Voltage in Secondary HO2S (Sensor 2) Circuit1. Do the PCM Reset Procedure.
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. Accelerate using wide open throttle. Then decelerate for at least 3 seconds with the throttle completely closed.
4. Check the Secondary HO2S (Sensor 2) output voltage with the scan tool.
Does the voltage stay at 0.9 V or more?
YES-Go to step 5.
NO-Intermittent failure, system is OK at this time. Check for poor connections or loose wires at C204 (located under the right side of the dash), C102 (located under the under-hood fuse/relay box), the Secondary HO2S (Sensor 2) and the PCM.
5. Turn the ignition switch OFF.
6. Disconnect the Secondary HO2S (Sensor 2) 4P connector.
7. Connect the Secondary HO2S (Sensor 2) 4P connector terminals No.1 and No.2 with a jumper wire.
8. Turn the ignition switch ON (II).
9. Check the Secondary HO2S (Sensor 2) output voltage with the scan tool.
Is there 0.9 V or more?
YES-Go to step 10.
NO-Replace the Secondary HO2S (Sensor 2).
10. Turn the ignition switch OFF.
11. Connect PCM connector terminals A23 and C18 with a jumper wire.
12. Turn the ignition switch ON (II).
13. Check the Secondary HO2S (Sensor 2) output voltage with the scan tool.
Is there 0.9 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 (A23) and the Secondary HO2S (Sensor 2).