JCB P3418-87 – Aftertreatment System ECU: Erroneous Signal for Operating Mode Request

The Aftertreatment System ECU has detected an incorrect or unexpected CAN bus signal related to the operating mode request. This affects the proper functioning of the machine's control system by preventing the initiation of a manual Diesel Particulate Filter (DPF) regeneration (referred to by JCB as the Refresh function). Because the system cannot recognize the mode request, it will not start the regeneration process, which can lead to severe aftertreatment system blockages and potentially force the machine into a reduced power mode.

• JS130
• JS200
• JS210
• JS220
• JS240
• JS260
• JS360
• 3CX
• 4CX
• 2CX

1. 1

   Verify the battery is fully charged and that all ground connections are clean and secure, as general electrical issues can trigger CAN bus errors

2. 2

   Visually inspect the wiring harness leading to the operator controls (mode selection switch/dial) and the Aftertreatment System ECU for signs of abrasion, melting, or pinching

3. 3

   Disconnect and inspect the relevant connectors for corrosion (green or white powder), bent or loose pins, and the presence of water or debris

4. 4

   Check the operating mode switch for a solid mechanical 'click' and proper physical operation

5. 5

   Test the operating mode switch for continuity and correct voltage signals according to the machine's service manual

1. 1

   Repair wiring and connectors

   Repair any damaged sections of the wiring harness or clean/replace faulty connectors identified during the visual inspection.

2. 2

   Replace operating mode switch

   If the operating mode switch fails mechanical or electrical testing, replace it with a new unit.

3. 3

   Clear fault codes and reset

   Once repairs are complete, clear the fault code from the ECU. Perform a key cycle by turning the machine off for 30-60 seconds to clear the fault from the system's memory.