FMI 5 – Current below normal or open circuit
Fault code explanation: Faulty sensor / Faulty sensor circuit
Fault indication: DCU: Engine warning in DCU display.
CIU: Flash code
Electrical fault: 5.4
Value fault: None
Symptom: Preheat relay never activated. White smoke for cold start.Start problems in
Conditions for fault code: The current through pin B25 or through pin B7 on the EMS2 deviates from
normal current value.
Possible reason: Open circuit in cable harness between EMS2 and preheat relay.
Suitable action: 1 Check all connections on the preheat relay and all cables between
EMS2 and preheat relay.
2 Check the contact pressure in socket 25 and in socket 7 in the engine
In cold climate the intake air might need too be pre-
heated. This is done by the preheater located on the
The activation of the preheater is con-
trolled by the EMS2 via the preheat relay. EMS2 pin
B25 activates the preheat relay. A sense wire is con-
nected between the preheater relay output and B7.
The sense wire checks that the preheat element and
the preheat fuse are not damaged.
Checking the wiring page 141
R / BL
A Connector B
30-2 Fault Tracing
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