Range Rover (LP) from 1999 model year

Bosch Motronic M5.2.1 EMS

Oxygen sensor heater downstream of catalyst bank B (rear right hand sensor)

DTC

Description

P0161

Oxy Sensor Heater Downstream Cat bank 2 Drive cycle C:Signal out of range - above maximum.

P0161

Oxy Sensor Heater Downstream Cat bank 2 Drive cycle C:Signal out of range - below minimum.

Possible Causes:
  1. Open circuit heater - oxygen sensor/3 to oxygen sensor/4.
  2. Open circuit C635/1 (WU) to C642/4 (WU).
  3. Open circuit C573/3 (NK) to C642/3 (NK).
  4. Fuse condition - F2 Engine Compartment Fusebox.
  5. Connector(s) C642,ECM C635 (B).

1. Open circuit heater - oxygen sensor/3 to oxygen sensor/4.

OPEN_CIRCUIT 

Check resistance > 1M&!

2. Open circuit C635/1 (WU) to C642/4 (WU).

OPEN_CIRCUIT 

Check resistance > 1M&!

3. Open circuit C573/3 (NK) to C642/3 (NK).

OPEN_CIRCUIT 

Check resistance > 1M&!

4. Fuse condition - F2 Engine Compartment Fusebox.

POWER_DISTRIBUTION 

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. e.g. Check if other circuits fed by the same fuse are also experiencing problems.

5. Connector(s) C642,ECM C635 (B).

CONNECTOR 

Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.