CAP 6W1461 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the starting system or if one of the diagnostic codes in Table 1 is active.
Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
444-5 Starter Motor Relay current below normal The Electronic Control Module (ECM) detects an open circuit and/or a short to the +Battery in the start relay. The ECM can only detect this condition when the start relay is not energized. The code is logged.
444-6 Starter Motor Relay current above normal The ECM detects a short circuit to ground in the start relay. The ECM can only detect this condition when the start relay is energized. The ECM has the ability to crank the engine when the Engine Control Switch (ECS) is placed in the START position. After the ECS is placed in the START position, the ECM will begin the prelube cycle. The ECM will send an engine start signal to terminal BH of the customer connector after the prelube cycle is complete. The customer's engine start signal will return on terminal BJ of the customer connector. The signal is then sent to terminal 10 of the G-C6 connector on the "Marine Power Display (MPD)" panel.If a "Starter Select Switch" is installed in the MPD panel, the switch can be set to use either the electric starting motors or the air starting motors. If electric starting motors are installed on the engine, the starting motor relays "SMMS1" and "SMMS2" will be energized. If air starting motors are installed on the engine, the air start solenoids will be energized. If a "Starter Select Switch" is not installed in the MPD panel, the start signal is routed from TB-8 to TB-7. The signal from TB-7 is wired to the starting system. The crank cycle will continue for the time that is equal to the cycle crank time that has been programmed or the crank cycle will continue until the engine speed reaches the crank terminate speed.Note: The prelube cycle can be disabled by setting the duration of the prelube cycle to 0.This process will repeat for a programmed amount of times "Total Number of Crank Cycles". If the engine does not start, Caterpillar Electronic Technician (ET) will display "OVERCRANK". The engine control will be in an idle state. The process can be restarted by turning the ECS to the OFF/RESET position. Next, turn the ECS to the STOP position. Then turn the ECS to the START position.The engine can be manually started by using the "crank override switch" which is located on the inside of the instrument panel.
Illustration 1 g01313474
Typical example
Illustration 2 g01242365
P2 ECM connector
(P2-6) Starter drive (+)
(P2-7) Return (-)
Illustration 3 g01242366
Customer connector
(Terminal BH) Start signal from ECM
(Terminal BJ) Start signal from customer
Illustration 4 g01234146
Location of ECM connectors
Test Step 1. Inspect Electrical Connectors and Wiring
Turn the ECS to the OFF/RESET position.
Turn the circuit breaker for the battery to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors.