electronic/pneumatic and hydraulic suspension systems testing. Checked for faults, no
faults in ME-SFI was a fault in ESP but not related to a no start issue. Performed fuel
pressure testing while cranking engine (0 bar) Performed electrical testing at fuse 13 in
trunk fuse box (ok). Removed the right side trunk panel and checked the relay K27 circuits
85 and 86, key on 12.13 volts. while cranking the engine, 10.1 volts both ok. Reinstalled
relay and raised the vehicle to get access to the fuel pump. Checked voltage signal
directly at pump while cranking engine (0 volts). Replaced the k27 relay and rechecked,
still 0 volts. Performed resistance test of wire from relay to fuel pump .03 ohms good
value. Ground wire tested at .03 ohms to ground ok. Test fuel pump across positive and
negative post was 1.0 ohm. Recommend replacing the fuel pump. After replacing fuel pump
and relay the engine failed to start. Once the engine ran for appxomitly 1 hour, performed
electrical testing of the BASE Module and inspected internally (did have incorrect fuses 2
were 20 amp and 1 was 30 amp), should all be 10 amp fuses. Noticed with fuel gauge
connected and the engine running, the voltage out of the fuel pump relay circuit 30/87 was
13.89 volts, voltage at signal inputs to relay from BASE module and ME-SFI module,
circuits 85/86, 13.89 volts and fuel pressure at 3.8 bar. When engine dies, 0 bar and 0
voltage for fuel pump, and 0 voltage for circuits 85/86. Found circuit 85 at relay, from
BASE module to ground is 11.98 volts. While cranking engine testing ground circuit from
ME-SFI circuit 86 to relay was 0 volts to positive. The ME-SFI is not sending the
grounding circuit 86 to the relay, therefore it doesn't close and has no voltage to the
fuel pump. Removed the right side ME-SFI and found it has labels that it has been sent for
repairs. It does have a burnt odor to it when it fails. Recommend replacing that control
module.
CA.