P0143

Tests 1 - 2:

Tests 3 - 7:

Test 8:

SYMPTOM
P0143 - 1/3 O2 SENSOR SHORTED TO GROUND

WHEN MONITORED
With engine coolant temperature above 170 °F on the previous key ON, after a cold start, engine coolant below 98 °F, and ambient/battery temperature sensor reading within 27 °F of engine coolant.

SET CONDITION
The oxygen sensor signal voltage is below 0.156 volts for 28 seconds after starting engine.

POSSIBLE CAUSES
- 1/3 O2 sensor
- 1/3 O2 sensor terminal
- 1/3 O2 sensor wiring harness intermittent short to ground
- PCM (1/3 O2 sensor shorted to ground)
- PCM terminal
- 1/3 O2 sensor signal circuit intermittent short to ground
- 1/3 O2 sensor signal circuit shorted to ground