0432759 JOHNSON THERMOSTAT

Table 1
Code and Description Conditions which Generate this Code System Response
110-3 Engine Coolant Temperature Sensor voltage above normal The engines Electronic Control Module (ECM) detects signal voltage that is more than 4.95 VDC for eight seconds.
The ECM has been powered for at least two seconds. The code is logged if the engine has been running for more than seven 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 eight seconds.
110-4 Engine Coolant Temperature Sensor voltage below normal The ECM detects signal voltage that is less than 0.2 VDC for eight seconds.
The ECM has been powered for at least two seconds.
172-3 Intake Manifold Air Temperature Sensor voltage above normal The engines ECM detects signal voltage that is more than 4.95 VDC for eight seconds.
The ECM has been powered for at least two 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 40 °C (104 °F).
172-4 Intake Manifold Air Temperature Sensor voltage below normal The ECM detects signal voltage that is less than 0.2 VDC for eight seconds.
The ECM has been powered for at least two seconds.
174-3 Fuel Temperature Sensor voltage above normal The engines Electronic Control Module (ECM) detects signal voltage that is more than 4.95 VDC for eight seconds.
The ECM has been powered for at least two 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 two seconds.
The ECM has been powered for at least two seconds.
175-3 Engine Oil Temperature Sensor voltage above normal The engines Electronic Control Module (ECM) detects signal voltage that is more than 4.95 VDC for eight seconds.
The ECM has been powered for at least two seconds. The code is logged. The ECM will flag the oil temperature as invalid data and the oil temperature is set to the engine coolant temperature.
175-4 Engine Oil Temperature Sensor voltage below normal The ECM detects signal voltage that is less than 0.2 VDC for two seconds.
The ECM has been powered for at least two 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 g01402850
Schematic for the passive analog sensors
Table 2
Troubleshooting Test Steps Values Results
1. Check for Active and Logged Diagnostic Codes
A. Remove electrical power from the ECM.
B. Connect Cat Electronic Technician (ET) to the service tool connector.
C. Restore electrical power to the ECM.
D. Monitor the diagnostic codes on Cat ET. Check and record any diagnostic codes.
Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
E. Determine if a diagnostic code has occurred several times.
Note: A diagnostic code that is logged several times is an indication of an intermittent problem. Most intermittent problems are the result of a poor connection between a socket and a pin in a connector or of a poor connection between a wire and a terminal.
F. Determine if the problem is active and related to one of the following diagnostic codes:
-3
-4
G. Remove electrical power from the ECM.
Diagnostic Code
Result: A diagnostic code is not active.
Repair: The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".
STOP
Result: An active -3 diagnostic code is present.
Proceed to Test Step 2.
Result: An active -4 diagnostic code is present.
Proceed to Test Step 4.
2. Check for Battery Voltage on the Signal Wire
A. Restore electrical power to the ECM.
B. Measure the voltage on the harness side of the sensor connector between pin 1 and engine ground for the suspect sensors.
C. Remove electrical power from the ECM.
Signal Voltage
Result: Remove electrical power from the ECM.
Result: The signal voltage is equal to battery voltage.
Repair: There is a short circuit to battery voltage in the harness. Repair the wiring harness or replace the wiring harness. Verify that the repair has resolved the original problem.
STOP
3. Create a Short Circuit at