P0156

DTC P0156
Lambda sensor downstream catalyst bank 2 Drive cycle C:Signal implausible.

DTC P0157
Lambda sensor downstream catalyst bank 2 Drive cycle C:Signal out of range - below minimum.

DTC P0158
Lambda sensor downstream catalyst bank 2 Drive cycle C:Signal out of range - above maximum.

DTC P0160
Lambda sensor downstream catalyst bank 2 Drive cycle C:Signal missing.

Possible causes by suggested order of priority:
^ Oxygen sensor heater not functioning correctly.
^ Open circuit C635/14 (G) to C642/2 (G).
^ Open circuit C635/8 (RB) to C642/1 (RB).
^ Connector(s) C642,ECM C635 (B).
^ Oxygen sensor damaged or surface contaminated.

Oxygen Sensor Heater Not Functioning Correctly.
CHECK THE FOLLOWING:
^ Oxygen sensor heater fault flags are set.
INFORMATION
^ If the oxygen sensor is not at the correct operating temperature the sensor may appear faulty to the motronic diagnostics system. This fault should be diagnosed by exploring the oxygen sensor heater faults which will be set if this fault is present.

Open Circuit C635/14 (G) to C642/2 (G).
OPEN_CIRCUIT
^ Check resistance > 1M Ohm

Open Circuit C635/8 (RB) to C642/1 (RB).
OPEN_CIRCUIT
^ Check resistance > 1M Ohm

Connector(s) C642,ECM C635 (B).
CONNECTOR
^ Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.

Oxygen Sensor Damaged Or Surface Contaminated.
CHECK THE FOLLOWING:
^ Remove the oxygen sensor and examine the side internal to the exhaust system and the side outside the exhaust system. Both sides of the sensor should be free from contamination. Gas must be able to be absorbed by both sides of the sensor.
^ Also check the sensor for any mechanical damage or cracks.
INFORMATION
^ If the oxygen sensor shows signs of damage or contamination that cannot be cleaned it should be renewed.