STATUS
CODE
DISPLAY MESSAGE RECOVERY METHOD CIRCUIT
8786-3 8786 Automatic RH Traction
Node 3
DESCRIPTION BEHAVIOR
Line Contactor or Electric Brake coil short to
Battery Positive (B+) detected - (RH Node 3)
Parking brake drops, all truck functions disabled.
Probable Causes and Test Procedures
1. Determine if Line Contactor or Electric Brake system is at fault:
a. Disconnect the Electric Brake (CPS24), does the fault go away?
YES- Problem is with electric brake system Proceed to Step 2.
NO- Brake system is not at fault Proceed to Step 5.
2. Check the electric Brake Coil to be between 15 to 20 Ohms?
YES- Brake coil not at fault, proceed to step 3.
NO- Brake coil fault, replace electric brake.
3. Check brake coil connections for short:
a. Measure between Pins 1 and 2 of CPS24 on harness side, is resistance > 1k Ohms?
YES- No harness fault found, controller driver may be at fault, Proceed to step 4.
NO- Locate shorted wires in harness, separate, and repair wires / pin / crimps.
4. Check controller brake coil driver for short:
a. Measure between Pin 4 of traction controller and B−, is there < 1k Ohm?
YES- Controller at fault, contact Service Engineering.
NO- No cause found, contact Service Engineering.
5. Determine if LC system is at fault:
a. Disconnect the line contactor coil (wire 075). Does the fault go away?
YES- Problem is with contactor system. Proceed to Step 6.
NO- Controller may be damaged, contact Service Engineering.
6. Check the Line Contactor Coil to be between 65 to 85 Ohms?
YES- Coil not at fault, proceed to step 8.
NO- Proceed to step 7.
2200 YRM 1415 Troubleshooting
25
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