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| Illustration 1 | g01294799 |
Connections for the fuel level sender | |
This diagnostic code is associated with the fuel level sender. The "Input high error" means that the IQAN-XT2 module has determined that the voltage of the circuit for the sender is above normal.
The possible causes of this diagnostic code are listed below:
- The signal circuit for the sender is shorted to ground.
- The sender has failed.
- The module has failed. This is unlikely.
Note: This circuit contains a 390 Ω resistor. The connections, the continuity, and the resistance value of this resistor should all be checked. The resistor is located in front of the swing motor between the tower plates of the upper frame on TK711 through TK732 machines. The resistor is located near the pilot manifold on the bottom side of TK741 through TK752 machines. The bottom cover plate must be removed in order to access the resistor on these machines.
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 "Input high error" for pin 36 of the IQAN-XT2 module is active before performing this procedure.
Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.
Test Step 1. CHECK THE SENDER
- Turn the disconnect switch and the key start switch to the ON position.
- Ensure that the diagnostic code is active.
- Observe the status of the diagnostic code. Disconnect the machine harness from the sender.
Expected Result:
The "Input high error" for pin 36 of the IQAN-XT2 module remains active.
Results:
- OK - The diagnostic code remains active. The sender is correct. Proceed to Test Step 2.
- NOT OK - The diagnostic code is no longer active. The sender has failed.
Repair: Replace the sender.
STOP
Test Step 2. CHECK THE WIRING HARNESS OF THE SENDER FOR A SHORT TO GROUND
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect the machine harness from the sender.
- Disconnect the machine harness connectors from the IQAN-XT2 module.
- At the machine harness connector for the module, measure the resistance from the signal contact IQAN XT2 A0 - 36 (wire 447-PK) of the machine harness to all possible sources of ground. Measure the resistance to all contacts of the machine harness connectors for the module.
Expected Result:
Each resistance measurement is greater than 5000 ohms.
Results:
- OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.
- NOT OK - One or more resistance measurements is not correct. There is a short in the machine harness.
Repair: The short is between signal contact IQAN XT2 A0 - 36 (wire 447-PK) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.
STOP
Test Step 3. CHECK THE STATUS OF THE DIAGNOSTIC CODE
- Inspect the harness connectors on the sensor, the resistor, and the module and clean the contacts of the harness connectors. Check the wires for damage to the insulation that is caused by excessive heat, battery acid, 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 making sure that the connectors are fully seated and the clips for each connector are completely fastened.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Check the status of the "Input high error" for pin 36 of the IQAN-XT2 module.
Expected Result:
The "Input high error" for pin 36 of the IQAN-XT2 module is active.
Results:
- YES - The "Input high error" for pin 36 of the IQAN-XT2 module is active. The diagnostic code has not been corrected. The module may have failed.
Repair: If the problem is still present, replace the sender. After the sender is replaced, perform this test step again. After sender replacement, if the problem is still present, the module may be faulty.Exit this procedure and perform the diagnostic code procedure again. If the problem persists, the module may have failed. Prior to replacing a module, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the cause of the diagnostic code is not found, replace the module.
STOP
- NO - The "Input high error" for pin 36 of the IQAN-XT2 module is not active. The diagnostic code does not exist at this time.
Repair: The initial diagnostic code was probably caused by a poor electrical connection at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.
STOP