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Old 01-24-2022, 10:26 PM   #7
fdryer
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Join Date: Jan 2006
Location: NYC
Posts: 45,745
 

2003 L-Series 3.0L Sedan
Default Re: No dash lights, no crank, no start

There are several issues you're addressing based on descriptions; starting, engine unable to run, and i/p not lighting up, gauges dead. With the starter circuit cranking the engine, this eliminates the starting circuits. The engine not running and gauges not operating points to the EFI system (engine) and bcm (gauges).

First things first. Security, Passlock, must be off during starting. As part of system self testing, security indicator turns on with all the i/p indicators then turns off as it passes self tests otherwise a fault would turn on security and remain on. This occurs when ignition is turned on. Security remaining on indicates internal self tests failed with Passlock disabling itself from interfering with everyday starting/driving. Normal operation is blinking when remotes are used to Lock doors/enable Passlock and off when remote unlocking/Passlock disabled. Flashing indicates a theft attempt or error with Passlock disabling injector operation - engine cranks but without injectors operating, the engine will never fire up. This is the theft deterrent mode.

Presuming security is off during starting, either the EFI system is failing somewhere and/or the bcm is failing to communicate a security password to allow normal EFI functions. Bcm interfering with ecm operation hasn't been reported as the bcm sends either a go or no go signal (security) to the ecm to allow the ecm to run the EFI system. If we presume the bcm isn't sending a no go signal to the ecm then EFI system troubleshooting can be broken down into two main issues - fuel or ignition. A third issue would be the simultaneous loss of injector operation and spark.

Troubleshooting fuel and spark are relatively easy. When turning the ignition switch ON, the ecm powers the fuel pump for two seconds then shuts down if the engine isn't started. Depressing the fuel rail test valve should result in fuel spraying out under pressure. Full pressure is developed in two seconds.

Troubleshooting spark requires cranking the engine with plug(s) and ignition coil(s) removed, reconnected over the engine to observe for spark on each plug. Plug bases wired to engine block ground. When removing plugs, note whether or not they're wet with fuel - this helps with diagnosing problems.

A faulty bcm does occur with Vue members finding used ones restoring bcm functions. Mileage is retained in bcm's and cannot be altered despite many stating so with none reporting success. Odometer tampering laws.
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