MODULE AR-DIESEL EXHAUST FLUID 4246216 - Caterpillar

When a problem exists with a switch and further troubleshooting is necessary to isolate the problem, refer to the Systems Operations, "Switches" section for additional information on the individual switches.The possible causes of these failures are listed below:
The signal circuit in the machine harness is open.
The switch has failed.
The ECM has failed.Test Step 1. CHECK FOR AN OPEN IN THE HARNESS
Locate the switch that corresponds to the indicator that is located on the display module. (If necessary, use the Electrical System Schematic to assist in locating the switch.)
Disconnect the signal wire from the switch.
Place a jumper wire from the signal wire to the ground wire. Expected Result:The alert indicator is no longer active on the main display module.Results:
OK - The alert indicator is no longer active on the main display module.Repair: The switch has failed. Check or replace the switch. STOP
NOT OK - The alert indicator remains on the main display module. The machine harness is open or the ECM has failed. Proceed to Test Step 2.Test Step 2. CHECK THE VOLTAGE OF THE ECM.
Remove the jumper that was used in the previous test step.
The signal wire remains disconnected.
Measure the pull-up voltage from the signal wire to the ground wire with a digital multimeter. Expected Result:The voltage is 8 0.5 VDC. Results:
OK - The voltage is 8 0.5 VDC. Repair: The voltage is correct. The ECM may have failed. A failure of the ECM is unlikely.If available, use the Cat® Electronic Technician (Cat ET) service tool to perform a “Wiggle Test” on the machine wiring harness. The wiggle test can detect intermittent shorts or opens in the machine wiring harness.Verify that all possible causes of the diagnostic code have been investigated. Exit this procedure and perform this procedure again. If the cause of the problem is not found, the ECM may have failed.Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the cause of the diagnostic code is not found and the ECM must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".STOP
NOT OK - The voltage is NOT 8 0.5 VDC. Proceed to Test Step 3.Test Step 3. CHECK THE SIGNAL CIRCUIT OF THE HARNESS.
Turn the key start switch and the disconnect switch to the OFF position.
Use the Electrical System Schematic to trace the signal wire from the switch back to the ECM.
Determine the signal contact (connector contact) of the machine harness at the ECM.
Disconnect the machine harness connectors J1 and J2 from the ECM.
At the machine harness connector for the ECM, measure the resistance between the signal contact and contact 2 of the switch. Expected Result:The resistance is less than 5 ohms. Results:
OK - The resistance is less than 5 ohms. The signal circuit of the harness is correct. Proceed to Test Step 4.
NOT OK - The resistance is greater than 5.0 ohms. Repair: The signal circuit of the harness is not