TURBOCHARGER GP 3856931 - Caterpillar

Illustration 1 g01897718
Connections of the air temperature switch
This diagnostic code is associated with the air temperature switch. This diagnostic code is recorded when the ECM reads the signal from the switch and the ECM determines that the signal is erratic, intermittent, or incorrect.The possible causes of this diagnostic code are listed:
An open circuit exists.
The ECM has failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 2659 FMI 02 is active before performing this procedure.Note: Use a digital multimeter for the measurements in this procedure.Test Step 1. VERIFY THE SOFTWARE VERSIONNote: Check and record the latest software version for the machine electronic controls from SIS.
Verify that the latest version of software has been loaded to the Brake ECM. Expected Result:All of the software is current.Results:
OK - All of the software is current. Proceed to Test Step 2.
NOT OK - There is a more recent software release that is available.Repair: Flash all controls with the latest software release. Refer to Troubleshooting, "Electronic Control Module (ECM) - Flash Program".STOPTest Step 2. CHECK THE HARNESS.
Turn the key start switch to the OFF position.
Inspect the harness.
Check for the proper mating.
Check the exposed wires for nicks and abrasions.
Check for moisture, dirt, or corrosion.
Check the pin/socket for a proper fit.
Disconnect the J1 machine harness connector from the Machine ECM.
Connect a jumper wire between the contact for the manual mode J1-14 (wire C539-YL(Yellow)) and the contact for the auto mode J1-25 (wire C540-GY(Grey)).
Disconnect the machine harness at the switch.
Measure the resistance between contact 1 (wire C540-GY(Grey)) and contact 3 (wire C539-YL(Yellow)) at the connector for the switch. Expected Result:The resistance should be less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. The machine harness is correct. Proceed to test step 3.
NOT OK - The resistance is greater than 5 ohms. There is an open in the machine harness. The open exists in the wire with the high resistance.Repair: There is an open connection or a bad connection in the switch input wire C540-GY(Grey) or wire C539-YL(Yellow). Refer to the complete Electrical System Schematic. Check the connectors that are in the switch circuits for loose connections or for corroded connections. Repair the machine harness or replace the machine harness. STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE.
Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, corrosion, or chafing.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
Reconnect all harness connectors. Make sure that the connectors are fully seated and that the clips for each connector are completely fastened.
Turn the disconnect switch and the key start switch to the ON position.
Operate the machine.
Determine if the CID 2659 FMI