P0135

DTC P0135
Oxy Sensor Heater Upstream Cat bank 1 Drive cycle C:Signal out of range - above maximum.

DTC P0135
Oxy Sensor Heater Upstream Cat bank 1 Drive cycle C:Signal out of range - below minimum.

Possible causes by suggested order of priority:
- Open circuit heater - oxygen sensor/3 to oxygen sensor/4.
- Open circuit C635/19 (WO) to C644/4 (WO).
- Open circuit C573/3 (NK) to C644/3 (NK).
- Fuse condition - F2 Engine Compartment Fusebox.
- Connector(s) C644,ECM C635 (B).

Open circuit heater - oxygen sensor/3 to oxygen sensor/4.
- Check resistance > 1M Ohm

Open circuit C635/19 (WO) to C644/4 (WO).
- Check resistance > 1M Ohm

Open circuit C573/3 (NK) to C644/3 (NK).
- Check resistance > 1M Ohm

Fuse condition - F2 Engine Compartment Fusebox.
- Check for fuse not correctly inserted, fuse blown, fuse connections loose, damaged or corroded.
- Certain diagnostics may also perform further checks to try and narrow down the fault. Eg Check if other circuits fed by the same fuse are also experiencing problems

Connector(s) C644,ECM C635 (B).
- Check for connector not correctly latched, backed out pins, damaged pins, corroded pins