DTC 43 - Fuel Temperature CKT High (Low Temp Indicated): Notes

Fuel temperature sensor is a thermistor that controls signal voltage to PCM. When fuel is cold, sensor resistance is high, and PCM will sense a high signal voltage. As fuel warms, sensor resistance becomes less and voltage drops. Fuel temperature sensor is integrated with the optical sensor.

DTC 43 will set when fuel temperature is less than 6°F (-14°C) and engine has been running for at least 2 minutes. PCM will default to poor idle quality during hot conditions.

1. This step determines if DTC 43 is the result of a hard failure or an intermittent condition.
2. This step simulates a DTC 42. If the PCM recognizes the low signal voltage (high temperature), PCM and wiring are okay.
3. This step determines if an open is present in the fuel temperature signal circuit. 5 volts should exist at sensor connector. This will determine if a wiring problem exists or if the PCM is faulty.