P0157

Test 1 - 3:

Test 4 - 8:

SYMPTOM
P0157-O2 SENSOR 2/2 VOLTAGE LOW

TEST NOTE
This symptom is diagnosed using the test P0131-O2 SENSOR 1/1 VOLTAGE LOW.

WHEN MONITORED
Engine Running for less than 30 seconds. O2 Sensor Heater Temperature less than 376° C (705° F) Battery voltage greater than 10.99 volts.

SET CONDITION
The oxygen sensor signal voltage is below 1.5 volts for 3 seconds. One trip Fault.

POSSIBLE CAUSES
- O2 sensor below 2.52 volts
- O2 sensor
- O2 return circuit shorted to ground
- O2 signal circuit shorted to ground
- O2 signal circuit shorted to O2 return circuit
- O2 signal shorted to heater ground circuit
- PCM return circuit
- PCM signal circuit