DTC P0139: Secondary HO2S (Sensor 2) Slow Response
- Reset the ECM/PCM (see page 11-312).
- 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.
- Check the secondary HO2S (Sensor 2) output voltage at 3,000 rpm (min-1) with the scan tool.
Does the voltage stay within 0.3-0.8 V for 2 minutes?
YES |
- Replace the secondary HO2S (Sensor 2). |
NO |
- Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the secondary HO2S (Sensor 2) and at the ECM/PCM. |
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