Circuit DescriptionThe coolant temperature sensor (CTS) is used by the electronic control module (ECM) to monitorthe temperature of the engine coolant. The coolant temperature is used by the ECM for theengine protection system and the timing and fueling control. Component LocationThe coolant temperature sensor is located on top of the thermostat housing. Shop TalkMake sure the airflow through the radiator is not obstructed. Cummins ISB CM550 (1990-94) Fault Code: 145 PID: 110 SPN: 110 FMI: 4 Engine Coolant Temperature 1 Sensor Circuit – Voltage Below Normal or Shorted to Low Source Cummins ISB CM550 (1990-94) Fault Code: 145 PID: 110...

Circuit DescriptionThe coolant temperature sensor is used by the electronic control module (ECM) to monitor thetemperature of the engine coolant. The coolant temperature is used by the ECM for the engineprotection system, timing, and fueling control. Component LocationThe coolant temperature sensor is located on the engine in the thermostat housing area. Shop TalkMake sure the airflow through the radiator is not obstructed. Cummins ISB CM550 (1990-94) Fault Code: 146 PID: 110 SPN: 110 FMI: 0 Coolant Temperature – Engine Protection Cummins ISB CM550 (1990-94) Fault Code: 145 PID: 110 SPN: 110 FMI: 4 Engine Coolant Temperature 1 Sensor Circuit –...

Circuit DescriptionThe intake manifold air temperature sensor is used by the ECM to monitor the engine intakeair temperature. The intake manifold air temperature signal is used by the ECM for engineprotection system, cold start aid, timing, and fueling control. Component LocationThe intake manifold air temperature sensor is located on the side of the intake manifold at the rear of the head. Shop TalkIf the sensor is functioning properly, compare the reading to the following table. Cummins ISB CM550 (1990-94) Fault Code: 151 PID: SPN: FMI: Coolant Temperature – Engine Protection Cummins ISB CM550 (1990-94) Fault Code: 146 PID: 110 SPN:...

Circuit DescriptionThe intake manifold air temperature sensor is used by the ECM to monitor the engine intakeair temperature. The intake manifold air temperature signal is used by the ECM for engineprotection system, cold start aid, timing, and fueling control. Component LocationThe intake manifold air temperature sensor is located on the side of the intake manifold at the rear of the head. Shop TalkIf the sensor is functioning properly, compare the reading to the following table. Cummins ISB CM550 (1990-94) Fault Code: 153 PID: 105 SPN: 105 FMI: 3 Intake Manifold Air Temperature Sensor Circuit Cummins ISB CM550 (1990-94) Fault Code:...

Circuit DescriptionThe intake manifold air temperature sensor is used by the engine control module (ECM) tomonitor the engine intake air temperature. The intake manifold air temperature signal is used by the ECM for engine protection system, cold start aid, timing, and fueling control. Component LocationThe intake manifold air temperature sensor is located on the side of the intake manifold at the rear of the head. Cummins ISB CM550 (1990-94) Fault Code: 153 PID: 105 SPN: 105 FMI: 4 Intake Manifold Air Temperature Sensor Circuit Cummins ISB CM550 (1990-94) Fault Code: 153 PID: 105 SPN: 105 FMI: 3 Intake Manifold Air...