P0155

Tests 1 - 3:

Tests 4 - 8:

SYMPTOM
P0155 - 2/1 O2 SENSOR HEATER FAILURE

WHEN MONITORED
With the engine at idle immediately after a cold start (engine < 147 °F and battery temperature ± 27 °F of engine temperature.

SET CONDITION
O2 sensor voltage > 3 volts for 30 to 90 seconds.

POSSIBLE CAUSES
- 2/1 O2 sensor connector damaged
- 2/1 O2 sensor ground circuit open
- ASD relay output circuit open
- O2 sensor heater failure
- 2/1 O2 sensor failure
- 2/1 O2 sensor heater element failure
- 2/1 O2 sensor heater failure does not reoccur