02 Sensor 1/2 Below Threshold

(P0137) 02 SENSOR 1/2 BELOW THRESHOLD





When Monitored and Set Condition
^ When Monitored: Start and drive vehicle greater than 32 km/h (20 MPH) and less than 89 km/h (55 MPH). Throttle open for a minimum 120 seconds. Coolant Temp greater than 70°C (158°F) and Catalytic Converter Temperature greater than 600°C (1112°F).
^ Set Condition: The 02 sensor voltage switches only 11 times or less from rich to lean within 20 seconds during monitoring. Two Trip Fault.

POSSIBLE CAUSES
- EXHAUST LEAK
- 02 SENSOR SIGNAL CIRCUIT
- 02 SENSOR GROUND CIRCUIT
- 102 SENSOR



Diagnostic Test
1. CHECK FOR CURRENT DTC





Turn the ignition on. With the DRBIII, read PCM DTCs.
Is this DTC present?
Yes >> For complete diagnosis of this DTC, refer to (P0137) 02 SENSOR 2/2 ABOVE THRESHOLD. 02 Sensor 2/2 Above Threshold
No >> Go To 2

2. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.

Note: Check connectors - Clean/repair as necessary. Poor pin to terminal connections can set DTCs. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors specific to this DTC. Wiggle the wires while checking for shorts and open circuits.

Note: Check for any Technical Service Bulletins that may apply.

Were there any problems found?
Yes >> Repair as necessary. Perform POWERTRAIN VERIFICATION TEST - VER 2 Powertrain Verification Test - Ver 2.
No >> The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition.