P308E

P308E00

Diagnosis information DME control unit

Fuel-pump control

Diagnostic conditions
The control unit must be active in order to test internal function sequences and diagnosable inputs/outputs.
In the event of a fault, check whether the fault is permanently >present<. To perform the check, erase the fault memory, meet the diagnostic conditions and read out the fault memory again.
- Ignition on

Possible fault causes
- mechanically sluggish
- Short circuit
- Faulty

Fault setting condition(s)
- Open circuit Phase clocking

NOTE:
Diagnosis/Fault finding.
- Check of function using drive link test
- Short circuit to B+/mutual short circuit or open circuit in the lines
- Plug disconnect and Fault memory delete
- Check electrical connection to the fuel pump for open circuit. Disconnect fuel pump plug, connect PWM to ground, if a short circuit to ground is detected --> Fuel pump faulty.
- Check plug connections and lines between the fuel pump unit and electrical fuel pump for continuity.