0391719 JOHNSON CARB ASSY., Lower, 90

Table 1
Diagnostic Codes Table    
Description    Conditions which Generate this Code    System Response    
110-3 Engine Coolant Temperature Sensor voltage above normal     The Electronic Control Module (ECM) detects signal voltage that is above normal for eight seconds.
The engine has been running for seven minutes.
An engine coolant temperature that is less than
−35 °C (−31 °F) will also activate this fault.     The code is logged.
The value of the parameter is set to
90 °C (194 °F).    
110-4 Engine Coolant Temperature Sensor voltage below normal     The ECM detects signal voltage that is below normal for eight seconds.
An engine coolant temperature that is greater than
140 °C (284 °F) will also activate this fault.     The code is logged.
The value of the parameter is set to
90 °C (194 °F).    
172-3 Intake Manifold Air Temperature Sensor voltage above normal     The ECM detects signal voltage that is above normal for eight seconds.
An intake manifold air temperature that is less than
−35 °C (−31 °F) will also activate this fault.     The code is logged.
The value of the parameter is set to
40 °C (104 °F).    
172-4 Intake Manifold Air Temperature Sensor voltage below normal     The ECM detects signal voltage that is below normal for eight seconds.
An intake manifold air temperature that is greater than
140 °C (284 °F) will also activate this fault.     The code is logged.
The value of the parameter is set to
40 °C (104 °F).    
174-3 Fuel Temperature Sensor voltage above normal     The ECM detects signal voltage that is above normal for eight seconds.
The ECM has been powered for two seconds.
A fuel temperature that is less than
−30 °C (−22 °F) will also activate this fault.     The code is logged.
The value of the parameter is set to
40 °C (104 °F).    
172-4 Fuel Temperature Sensor voltage below normal     The ECM detects signal voltage that is below normal for eight seconds.
The ECM has been powered for two seconds.
A fuel temperature that is greater than
140 °C (284 °F) will also activate this fault.     The code is logged.
The value of the parameter is set to
40 °C (104 °F).    System OperationUse this procedure to troubleshoot any suspect problems with the following sensors:
Engine coolant temperature sensor
Intake manifold air temperature sensor
Fuel temperature sensorThe sensor signal for the passive sensors is routed to terminal 1 of each sensor connector. The analog return for the passive sensors is routed from the ECM to terminal 2 of each sensor connector.
Illustration 1 g01382552
Schematic for the analog sensors
Illustration 2 g01382557
Locations of the 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 g01372463
Terminal locations at the P2 ECM connector for the analog sensors (P2-13) Engine coolant temperature (P2-30) Sensor return (P2-58) Intake manifold air temperature (P2-62) Fuel temperature
Illustration 4 g01215524
Terminal locations at the sensor connector for the analog sensors (Terminal 1) Sensor signal (Terminal 2) Sensor returnTest Step 1. Check for "Active" or "Logged" Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore power to the ECM.
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.
Determine if the problem is active and related to one of the following failure mode identifiers:
3 Voltage above normal
4 Voltage below normalExpected Result:No diagnostic codes are active at this time.Results:
OK - No diagnostic codes are active at this time.Repair: There may be an intermittent electrical problem. If an intermittent electrical problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for information that is related to troubleshooting intermittent electrical problems.STOP
Not OK - An active 3 diagnostic code is present. Proceed to Test Step 2.
Not OK - An active 4 diagnostic code is present. Proceed to Test Step 4.Test Step 2. Check for a Short Circuit to the +Battery at the Sensor Connector
Measure the voltage on the harness side of the sensor connector between pin 1 and pin 2 for the suspect sensor(s).Expected Result:The supply voltage is less than battery voltage.Results:
OK - The supply voltage is less than battery voltage. Proceed to Test Step 3.
Not OK - The supply voltage is equal to battery voltage.Repair: There is a short in the harness to the +Battery. Repair the harness wiring, when possible. If necessary, replace the harness.STOPTest Step 3. Create a Short Circuit at the Sensor Connector
Disconnect the suspect sensor.
Fabricate a jumper wire that is long enough to create a short circuit across the connector for the suspect sensor. Crimp connector pins to each end of the jumper wire.
Disconnect the connector from the suspect sensor.
Use the wire jumper in order to create a short between terminal 1 (sensor signal) and terminal 2 (analog return) at the sensor connector.
Restore power to the ECM.
Access the "Active Diagnostic Code" screen on Cat ET. Check for an active 4 diagnostic code for the suspect sensor.Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Remove power from the ECM.Expected Result:A 4 diagnostic code is now active for the suspect sensor(s).Results:
OK - A 3 diagnostic code was active before creating the short at the sensor connector. A 4 diagnostic code became active after creating the short at the sensor connector.Repair: Temporarily connect a new sensor to the harness, but do not install the new sensor in the engine. Verify that there are no active diagnostic codes for the sensor. If there are no active diagnostic codes for the sensor, permanently install the new sensor. Clear any logged diagnostic codes.STOP
Not OK - A 3 diagnostic code is still active for the suspect sensor(s). Proceed to Test Step 5.Test Step 4. Create an Open Circuit at the Connector for the Suspect Sensor
Remove power from the ECM.
Disconnect the sensor connector of the suspect sensor(s) with the active 4 diagnostic code.
Res