SPACER 8M6238 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with a prelubrication system or if one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
338-5 Pre-lube Relay open circuit The engine's Electronic Control Module (ECM) detects an open circuit at the prelube pump relay.
The ECM detects a short to battery voltage at the prelube pump relay.
The ECM can only detect this condition when the prelube pump relay is not energized. The code is logged.
338-6 Pre-lube Relay short to ground The ECM detects a short circuit at the prelube pump relay.
The ECM can only detect this condition when the prelube pump relay is not energized. The ECM has the ability to automatically prelube the engine before cranking. This prelubrication may increase the life of certain engine parts. The ECM will prelube the engine, when the Engine Control Switch (ECS) is placed in the START position or the AUTO position and the remote start/run/stop switch is closed. The length of time for the prelube cycle can be programmed by the customer. The prelube cycle will end when the prelubrication pressure switch opens or if the customer programmed time ends. The engine speed must equal zero rpm before the prelube will begin.The prelube cycle has the following status codes."OFF" - The ECM is powered and the ECS is in the STOP position."ON" - The ECM is powered and the ECS is in the START position."COMPLETED" - The prelube has timed out or the prelubrication pressure switch has activated."DISABLED" - The engine prelube duration is programmed to 0.A test on Caterpillar Electronic Technician (ET) allows the technician to activate the prelube system. The test is functional when the engine speed is 0 rpm. The test is accessed by selecting the following menus on Cat ET:
"Diagnostics"
"Diagnostic Tests"
"Override Parameters"
Illustration 1 g01218512
Typical schematic
Illustration 2 g01218513
P1 ECM connector
(P1-5) Digital return
(P1-66) Prelubrication pressure switch
Illustration 3 g01234146
Location of ECM connectors
Illustration 4 g01218514
P2 ECM connector
(P2-12) Prelube relay
Illustration 5 g01218515
"Connector A"
(Terminal 1) −Battery
(Terminal 16) Prelube relay
(Terminal 19) +Battery
Illustration 6 g01218516
"Connector B"
(Terminal 1) Prelube motor Test Step 1. Inspect Electrical Connectors and Wiring
Remove electrical power from the ECM.
Thoroughly inspect the ECM connectors. Inspect all of the other connectors for the circuit. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and wiring are OK. 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