BLOCK A 2Y3764 - Caterpillar

Illustration 5 g00726034
+5 V supply circuitTest Step 1. Inspect Electrical Connectors And Wiring.
Illustration 6 g00728298
Terminal locations for ECM
Thoroughly inspect the following connections:
ECM engine harness connector J2/P2
ECM machine harness connector J1/P1
Turbocharger outlet pressure sensor J200/P200
Engine oil pressure sensor J201/P201
Atmospheric pressure sensor J203/P203
Fuel pressure sensor J208/P208
Right turbocharger inlet pressure sensor J205/P205Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the +5 V sensor supply:
P2-2 Engine Pressure Sensor +5 V (G828-WH)
P1-2 Engine Pressure Sensor +5 V (GL730-OR)
P2-3 Engine Pressure Sensor Common (G829-GN)
P1-3 Engine Pressure Sensor Common (993-BN)Refer to Illustration 6.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the harness and wiring for abrasion and pinch points from the sensors back to the ECM.Expected Result:All connectors, pins and sockets should be completely coupled and/or inserted and the harness and wiring should be free of corrosion, abrasion or pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - 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. Connect an Electronic Service Tool and Check for Active Diagnostic Codes.
Connect an electronic service tool to the cab data link connector.
Turn the keyswitch to the ON position while the engine is OFF.
Monitor the active diagnostic code screen of the electronic service tool. Check and record any active diagnostic codes.Note: Wait at least 15 seconds in order for the diagnostic codes to become active.Expected Result:Select the condition of the following codes:
262-03 5 Volt Sensor Supply short to +batt
262-04 5 Volt Sensor Supply short to groundResults:
Active - Proceed to Test Step 3.
Logged ONLY - Proceed to Test Step 5.
Not Active or Logged - The +5 V supply is operating correctly at this time.STOPTest Step 3. Disconnect The ECM Engine Harness Connector From The ECM.
Connect an electronic service tool to the cab data link connector.
Turn the keyswitch to the OFF position while the engine is OFF.
Disconnect ECM engine harness connector J2/P2.
Turn the keyswitch to the ON position while the engine is OFF.
Access the active diagnostic code screen on the electronic service tool. Check for one of the following active diagnostic codes:
262-03 5 Volt Sensor Supply short to +batt
262-04 5 Volt Sensor Supply short to groundNote: When ECM engine harness connector J2/P2 is disconnected and the keyswitch is in the ON position, open circuit diagnostic codes will be "Active" or "Logged" for all of the engine sensors. This is normal.Expected Result:The +5 V diagnostic code is active when the ECM engine harness connector is disconnected.Results:
Yes - The +5 V diagnostic code is active when the ECM engine harness connector is disconnected.Repair: Temporarily connect a test ECM to ECM machine harness connector J1/P1. Recheck for a +5 V diagnostic code. If a +5 V diagnostic code is not active, the original ECM is faulty.