P0131

Test 1 - 4:

Test 5 - 6:

SYMPTOM
P0131-O2 SENSOR 1/1 CIRCUIT VOLTAGE TOO LOW

WHEN MONITORED
At a cold start, engine coolant below 98° F, Ambient/Battery Sensor reading within 27° F, and Engine Coolant Temperature above 170° F on the previous key off

SET CONDITION
The Oxygen Sensor signal voltage is below 0.156 of a volt for 28 seconds after starting engine.

POSSIBLE CAUSES
- O2 sensor below 0.16 of a volt
- O2 Sensor operation
- O2 Sensor signal circuit shorted to ground
- O2 Sensor signal circuit shorted to (K4) sensor ground circuit
- O2 Sensor signal shorted to the heater ground circuit
- PCM