J1939 Datalink Multiplexing
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Overview
CODE | REASON | EFFECT |
Fault Code: 286 PID: S231 SPN: 639 FMI: 13/13 LAMP: Yellow SRT: |
The ECM expected information from a multiplexed device but only received a portion of the necessary information. |
At least one multiplexed device will not operate properly. |
![]() J1939 Datalink Multiplexing Circuit
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Circuit Description
Inputs such as throttle pedals, switches, and sensors can be communicated to the ECM over the J1939 datalink. Messages sent from the vehicle electronic control units (VECU) are received by the ECM and used for controlling the engine. Both the ECM and VECU must be properly configured so that each device’s information is transmitted by the VECU and received by the ECM.
Component Location
The ECM is located on the intake side of the engine, near the front. The J1939 datalink wiring and VECU(s) vary by OEM options.
Shop Talk
This fault occurs when the ECM is set up to receive information from several multiplexed switches from VECU(s) and only gets some of the switches. It indicates the ECM is setup to receive too many switches or the VECU(s) is set up to transmit too few switches.
Refer to Troubleshooting Fault Code t05-286.