SEAL AS 1251286 - Caterpillar

System Operation Description:The Electronic Control Module (ECM) supplies a regulated voltage of 8.0 0.4 VDC to the following sensors:
Engine coolant level
Auxiliary temperatureThese sensors are optional equipment.+8 VDC is routed from the ECM to terminal A of each digital sensor connector.
263-03 Digital Sensor Supply short to +batt
263-04 Digital Sensor Supply short to groundA +8 V diagnostic code is probably caused by a short circuit to ground or a short circuit to another voltage source in the harness. The next likely cause is a problem with a sensor. The least likely cause is a problem with the ECM.Note: The harness for the auxiliary temperature sensor includes a resistor assembly that is installed between the customer connector and the sensor connector. A short circuit across the resistor may cause active diagnostic codes for the sensor supply. Refer to Troubleshooting, "Auxiliary Temperature Sensor - Test" for a suspected problem with the resistor.
Illustration 1 g01149190
Schematic for the digital sensor supply
The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01146374
Left side engine view (typical example) (1) J1/P1 ECM connector
Illustration 3 g01146383
Left side engine view (typical example) (2) P61 Customer connector
Thoroughly inspect connectors (1) and (2). Inspect the connectors for each digital sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 4 g01128835
P1 ECM connector (P1-3) Analog sensor return (P1-4) +8 V Digital supply (P1-5) Digital return (P1-46) Coolant level (P1-68) Auxiliary temperature
Illustration 5 g01119753
J61 and P61 customer connectors (8) +8 V Digital supply (9) Digital return
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the digital sensor supply.
Check the allen head screw on the ECM connectors and the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from the battery to the ECM.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and wiring are okay. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Turn the keyswitch to the ON position.
Observe the active diagnostic code screen on Cat ET. Wait at least 15 seconds so that any codes may become active. Look for these codes:
263-03
263-04 Expected Result:One of the above diagnostic codes is active:Results:
Active 263-03 code - A 263-03 diagnostic