The engine control module (ECM) sends serial data to the body control module (BCM) along the primary serial data bus circuit. Serial data is then sent to the instrument cluster along the secondary serial data bus circuit. The following data is read by the instrument cluster, which then indicates the status as appropriate on the multifunction display (MFD) and/or cluster warning indicators:

A powertrain interface module (PIM) is required to convert the serial data generated by the ECM into serial data that is compatible with the BCM. DTC 11 will set if there is no powertrain control module (PCM) data message on the bus for more than 10 seconds. In practice, the trouble code is set somewhere between 10 and 20 seconds after the last PCM data message is received by the instrument cluster. The DTC is reset within 10 seconds of the arrival of a PCM data message on the bus. The DTC is logged as a History DTC.

By manipulating the harnesses at the various connectors it is often possible to isolate the cause of the circuit interruption. This harness can then be removed and repaired. Inspect for any damage to the harness which could cause an intermittent open circuit or backed out terminals at the instrument cluster connectors, broken connector locks, improperly formed or damaged terminals. The multimeter allows continuity of the wiring harness secondary serial data bus circuit to be checked. If the fault cannot be found in the harness, then the fault may lie in the PCM, PIM or the BCM. Refer to Diagnostic Starting Point - Computer/Integrating Systems for further diagnosis.