|DTC P0139 (63-3):||Secondary HO2S (Sensor 2) Slow Response|
|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 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).n
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.n