MID 128, PSID 201 Data link, MID144
FMI 9– Abnormal update rate
Fault code explanation: Communication error.
Fault indication: DCU: Engine warning in DCU display.
Electrical fault: None.
Value fault: None.
Conditions for fault code: No communication with the engine control unit.
Possible reason: • An open circuit in CAN H or CAN L or both CAN links between EMS 2
An open circuit in Power supply 0V cable between EMS 2 and DCU/
An open circuit in Power supply input cable between EMS 2 and DCU/
• CAN H short circuited to power supply in pin 4.
Suitable action: 1 Check contact pressure in socket 51 and 55 in engine connector B.
2 Check for an open circuit or short circuit between cables in the cable
harness between the DCU/CIU and EMS 2, via the engine connector.
A CAN H – Data Link to Engine
B CAN L – Data Link to Engine
C Power supply negative
D Power supply positive
G J1708A – Data Link to Engine
H J1708B – Data Link to Engine
Checking the CAN bus cable page
a A27 Engine connector
30-2 Fault Tracing
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