DTC 45

Fig. 81 - Chart #45 Diagnosis:

Code 45 Indicates ECM Detected High Oxygen Sensor Voltage:
- For Longer Than The Specified Time (about 2 minutes)
- Above a Specified TPS Value
- During Closed Loop Operation

NOTE: A high voltage can be caused by excess HC in the exhaust or an O2 sensor contaminated with silicone.

1. Checks to see if fault is still present. A dwell of under 50° indicates engine should be checked for cause of intermittent rich condition: i.e.,
a. Purge or bowl vent valves leaking.
b. Fuel in crankcase.
c. Fuel in evaporative canister.
d. Sticking mixture control solenoid or metering rods.
2. This step causes a lean condition by putting an air leak into the engine to see if ECM can respond. A drop in the dwell indicates ECM and O2 sensor are not faulty. Look for source of constant rich condition. See step one examples.
3. This step tests to see if ECM is able to respond to a lean exhaust O2 signal (low voltage). If no dwell change with a grounded lead to O2 sensor Term. "9", fault is in ECM. It couldn't be an open O2 wire because that would set Code 13.
4. This step checks the voltage from the ECM at the O2 sensor harness. Normal voltage at this point is the ECM bias voltage for no O2 signal which is approximately .45V. If voltage is high, the wire to the ECM could be shorted to B+, or it is a faulty ECM.