FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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81 Hex

Left Bank Downstream HO2S Stays At Center:






Trouble Code Number
- Scan tool 129
- General scan tool P0140
- MIL 21

Fault Message
- Left bank Downstream O2S Stays at Center

Background
- Sensor output voltage is checked.
- If voltage stays at center instead of switching, an open circuit is likely.

Range of Check
- 2 or more minutes after starting engine
- Engine coolant temperature: More than 80°C (176°F).

Set Condition
- Neither rich nor lean condition is detected from the Left bank downstream heated oxygen sensor input. (Voltage is 0.5 volts for 1.5 minutes)

Probable Cause
- Left bank downstream heated oxygen sensor failed
- Wiring harness and connectors failed
- PCM failed