PM620, PM622, PM820, PM822 and PM825 Cold Planers Electronic System Condition Switch (Switch to Ground) - Test Caterpillar

Steering ECM

When any of the combinations in Table 2 occur for more than 2 seconds, a level 2 warning is activated and logged. The Rotor door open and close functionality is disabled. Control reverts to the normal moldboard position control as outlined in the moldboard position control requirements (except for the Moldboard Raised Position Switch). When any of the above faults are active, the Moldboard Raised Position Switch is ignored. The moldboard is allowed to raise indefinitely. The rotor door open and close functionality is disabled when this fault is active until the switch combination is one of the five expected combinations.

Possible Causes for an FMI 2 Diagnostic Code are:

A short circuit exists in the wiring.

An open circuit exists.

The switch has failed.

The ECM has failed. A failure of the Steering ECM is unlikely.

Moldboard Position Mismatch

If a position switch fails or another unexpected condition occurs, the combination could be different from what is expected The table below summarizes the switch combinations that will not occur under normal conditions and shall result in the corresponding FMI diagnostic.

If any of the above combinations occur for more than 2 seconds, a level 2 event shall become active and logged. The rotor door open and close functionality shall be disabled and the control shall revert to the normal moldboard position control as outlined in the moldboard position control requirements with the exception of the Moldboard Raised Position Switch. When any of the above faults are active, the Moldboard Raised Position Switch shall be ignored and the moldboard shall be allowed to be commanded to raise indefinitely. The rotor door open and close functionality shall remain disabled while this event is active until the switch combination is one of the five expected combinations.

Illustration 1	g06028597
Illustration of the Switch-to-Ground schematic for the Steering ECM.

The Electrical System Schematic of the machine is shown in the Service Manual.

Refer to the appropriate media number below for the complete Electrical Schematic:

(S/N: JCF; LH9; 8RF; EL6) Machines refer to Electrical Schematic, UENR6397.

(S/N: JB9; JFC; LB8; FG4; TPH; XS6) Machines refer to Electrical Schematic, UENR6398.

(S/N: JB7; HN8; HC8; RL3; H6S; 626) Machines refer to Electrical Schematic, UENR8363.

(S/N: SL8; TLZ; ESE; AK5; AN8; EE2; E8S; 3C6; 627) Machines refer to Electrical Schematic, UENR8362.

The schematic will illustrate locations for all the electrical components and harness connectors that are installed on the machine.

Diagnostic Trouble Code Procedure

Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. Check the wiring for pinch points or abrasions. Look for and repair areas that indicate wires are exposed. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing a troubleshooting procedure.