WASHER 3V2431 - 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
Code and Description Conditions which Generate this Code System Response
338-5 Engine Pre-Lube Pump Relay current below normal The engine's Electronic Control Module (ECM) detects an open circuit at the prelube relay.
The ECM detects a short to battery voltage at the prelube relay. The code is logged.
338-6 Engine Pre-Lube Pump Relay current above normal The engine's ECM detects a short circuit at the prelube relay. 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. The ECM will prelube the engine, when the ECS is placed in 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 "prelube pressure switch" closes or when 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", "ON", "COMPLETED" and "DISABLED".The "OFF" status is entered when the engine control is first powered up with the ECS in the STOP position.The "ON" status is entered when the ECM is on with the ECS in the START position.The "COMPLETED" status is entered when the engine prelube duration is reached or when the engine prelube's pressure switch is activated.The "DISABLED" status is entered when the engine prelube duration is programmed to 0.The prelube function will be aborted when one of the following conditions occur:
The "prelube pressure switch" is activated.
The user defined engine prelube duration has been reached.
The operator activates the prelube override switch.When the ECM is in the START position, the ECM will activate the output driver for the "PPR1" relay. When the "PPR1" relay energizes, the normally open contacts of the "PPR1" relay close. This allows current to flow to the prelube motor. The prelube motor activates the prelube pump. The prelube pump builds pressure in the engine's lubrication system. When the "prelube pressure switch" closes as a result of the increased pressure, the ECM input for the "prelube pressure switch" is taken low. The ECM then knows that the pressure in the prelube system is adequate. The ECM will begin the starting sequence.
Illustration 1 g01325464
Typical schematic
Illustration 2 g01325606
P1 Primary ECM connector
(P1-5) "Digital return"
(P1-66) "Prelube override switch"
Illustration 3 g01325604
P2 Primary ECM connector
(P2-12) "Prelube drive"
(P2-66) "Digital return"
Illustration 4 g01325611
Terminal locations for the P-C1/A-C90 Connector for the power distribution panel
(Terminal c) "Prelube drive +"
(Terminal O) Drive for the prelube motor
(Terminal R) Return for the prelube motor
Illustration 5 g01325633
Terminal locations for the P-C2/A-C91 Connector for the power distribution panel
(Terminal d) Contacts for the prelube motor
(Terminal e) Contacts for the prelube motor
Illustration 6 g01325642
Terminal locations for the following connectors G-C6/F-C2/F-C1/A-C92 Connectors for a