RETAINER GP 7T3409 - Caterpillar

System Operation Description: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    
Description    Conditions which Generate this Code    System Response    
172-3 Intake Manifold Air Temperature Sensor voltage above normal     The engine's Electronic Control Module (ECM) detects signal voltage that is more than 4.8 VDC for one second.
The ECM has been powered for at least three seconds.     The code is logged.
The value of the parameter is set to zero.    
172-4 Intake Manifold Air Temperature Sensor voltage below normal     The ECM detects signal voltage that is less than 0.2 VDC for one second.
The ECM has been powered for at least three seconds.    System OperationUse this procedure to troubleshoot any suspect problems with the inlet manifold air temperature sensor.The sensor signal for the passive sensor is routed from the ECM to terminal 1 of the sensor connector. The sensor return for the passive sensor is routed from the ECM to terminal 2 of the sensor connector.
Illustration 1 g01212599
Typical schematic
Illustration 2 g01212602
P1 ECM connector (P1-3) Analog return (P1-14) Inlet manifold air temperature sensor
Illustration 3 g01234146
Location of ECM connectors
Illustration 4 g01163206
Sensor connector (Terminal 1) Inlet manifold air temperature sensor (Terminal 2) Analog return
Illustration 5 g01215177
Left side view (1) Inlet manifold air temperature sensorTest Step 1. Check for "Active" or "Logged" Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore electrical 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 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.
Determine if the problem is active and related to one of the following diagnostic codes:
-3
-4Expected Result:A diagnostic code is not active.Results:
OK - A diagnostic code is not active.Repair: The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Inspecting Electrical Connectors".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 3.Test Step 2. Create a Short at the Sensor Connector
Remove electrical power from the ECM.
Disconnect the suspect sensor.
Use a wire jumper in order to create a short between terminal 1 (signal) and terminal 2 (sensor return) at the sensor connector.
Restore electrical power to the ECM.
Access the "Active Diagnostic Code" screen on Cat ET. Check for an active -4 diagnostic code for the suspect sensor.
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