WEDGE 8Y7204 - Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the sensor or if any one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table    
Code and Description    Conditions which Generate this Code    System Response    
110-3 Engine Coolant Temperature Sensor voltage above normal     The engine Electronic Control Module (ECM) detects signal voltage that is more than 4.95 VDC for 8 seconds.
The ECM has been powered for at least 2 seconds.     The code is logged if the engine has been running for more than 7 minutes. The ECM uses the last valid engine coolant temperature. If the diagnostic code is active at start-up the ECM will use intake manifold temperature. If intake manifold air temperature is not valid, the ECM will default to
90 °C (194 °F) for engine coolant temperature. The ECM will activate the cooling fan after this code has been active for more than 8 seconds.    
110-4 Engine Coolant Temperature Sensor voltage below normal     The ECM detects signal voltage that is less than 0.2 VDC for 8 seconds.
The ECM has been powered for at least 2 seconds.    
172-3 Intake Manifold Air Temperature Sensor voltage above normal     The engine ECM detects signal voltage that is more than 4.95 VDC for 8 seconds.
The ECM has been powered for at least 2 seconds.     The ECM will log the diagnostic code. The ECM will flag the intake manifold air temperature as invalid data and the intake manifold air temperature is set to a default value of
70 °C (158 °F).    
172-4 Intake Manifold Air Temperature Sensor voltage below normal     The ECM detects signal voltage that is less than 0.2 VDC for 8 seconds.
The ECM has been powered for at least 2 seconds.    
174-3 Fuel Temperature Sensor voltage above normal     The engine Electronic Control Module (ECM) detects signal voltage that is more than 4.95 VDC for 8 seconds.
The ECM has been powered for at least 2 seconds.     The code is logged. The ECM will flag the fuel temperature as invalid data and the fuel temperature is set to a default value of
40 °C (104 °F).    
174-4 Fuel Temperature Sensor voltage below normal     The ECM detects signal voltage that is less than 0.2 VDC for 2 seconds.
The ECM has been powered for at least 2 seconds.    System OperationUse this procedure to troubleshoot any suspect problems with the following sensors:
Coolant temperature sensor
Intake manifold air temperature sensor
Fuel temperature sensorThe sensor signal for the passive sensor is routed from the ECM to terminal 1 of each sensor connector. The sensor return for the passive sensors is routed from the ECM to terminal 2 of each sensor connector.
Illustration 1 g01365935
Schematic for the passive analog sensors
Illustration 2 g03125297
Locations of the components for the passive analog sensors (typical left side engine view) (1) Engine coolant temperature sensor (2) Fuel temperature sensor (3) Intake manifold air temperature sensor (4) J2/P2 ECM connectors
Illustration 3 g01250277
Terminal locations