Engine Management

Left Bank Upstream HO2S Stays At Center Chart:

Trouble Code Number
- Scan tool 32
- General scan tool P0134
- MIL 21

Fault Message
- Left Bank Upstream HO2S 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 minutes after starting engine
- Engine coolant temperature: More than 80°C (176°F)

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

Probable Cause
- Left Bank Upstream Heated oxygen sensor failed
- Sensor signal circuit open
- PCM failed