Possible Causes
NOTE:
This DTC is set when the powertrain control module measures a signal that remains low when transitions are expected.
- The powertrain control module measures a signal that remains low when transitions are expected
- Battery disconnection resulting in errors in engine off time (short soaks may look like long soaks)
- Electric block heater applied and not detected
- Charge air temperature sensor circuit, short circuit to ground, short circuit to power, open circuit, high resistance
- Connector is disconnected, connector pin is backed out, connector pin corrosion
- Charge air temperature sensor failure
- Changeover valve - Fuel Fired Booster Heater (FFBH) system failure
- This valve should only allow coolant into the engine if the engine coolant temperature is -25° C (-13°F) or below. When de-energized, the changeover valve connects the heater coolant circuit to the engine coolant circuit. When energized, the changeover valve isolates the heater coolant circuit from the engine coolant circuit. If this valve is de-energizing above -25°C (-13°F) it will be inadvertently allowing heated coolant into the engine and causing the DTC to set due to a mismatch between coolant temperature sensor 1 and all the other temperature sensors