Checking Components And Wiring
- Check the resistance of the engine coolant temperature sensor
- Check the cable between combustion preheater module (CPM) terminal #4 and the ground terminal for the engine coolant temperature sensor. Check for a short-circuit to ground.
HINT: It is difficult to separate the ground lead for the engine coolant temperature sensor from the signal cable. Therefore, measure one cable at a time and, see if plausible values are obtained from either of them.
Remedy as necessary.
Other information
- see CONNECTING THE BREAKOUT BOX
- see SIGNAL SPECIFICATION
- For resistance values: COMPONENTS RESISTANCE VALUES
- see OVERHEAT PROTECTION THERMOSTAT / FLAME SENSOR / ENGINE COOLANT TEMPERATURE SENSOR, REPLACING
- see CHECKING WIRING AND TERMINALS
- Continue
Refer to VERIFICATION
- Check the combustion preheater module (CPM) connectors. Check for contact resistance and oxidation
- Check the cable between combustion preheater module (CPM) terminal #16 and the signal terminal for the engine coolant temperature sensor. Check for an intermittent short-circuit to ground.
Remedy as necessary.
Other information
- see CONNECTING THE BREAKOUT BOX
- see SIGNAL SPECIFICATION
- For resistance values: COMPONENTS RESISTANCE VALUES
- see OVERHEAT PROTECTION THERMOSTAT / FLAME SENSOR / ENGINE COOLANT TEMPERATURE SENSOR, REPLACING
- see CHECKING WIRING AND TERMINALS
- Continue
Refer to VERIFICATION