strange electrical issue '00 Beetle

[RoundHouse]

alright, gonna try to 'splain this the best I can

00 Beetle, wouldnt start, engine would spin over, but not start,

checked around, the selenoid on the injection pump had low voltage, ~7 volts.

I run jumper wire from battery to selenoid and engine will crank

I find fuse in box thats hot on crank and run and run jumper wire from there to selenoid.

engine runs but no power, turbo not spooling up.

also when you cut engine off the "brake" light stays on, something beeps, and the airbag light flickers. unless you put it in reverse before you cut it off, then that doesnt happen.

Im guessing there is a problem with power coming from some relay that powers the selenoid, but looked at a couple of diagrams and have not been able to make heads or tails of it.

 

[RoundHouse]

kept messing with it, but no progress so far.

this is bizzare.

 

[Alchemist]

When you turn the key on, does the glow plug light come on?

The ECU gets a wake up signal from the ignition switch, then sends a turn on signal to relay 109 which supplies power to the ECU. If the relay turns on, the glow plug light will come on briefly as part of the self test at start up.

If the glow plug light doesn't come on, replace the relay 109. If it has a black case, replace it anyways with the grey case relay.

The fuel shut off solenoid gets its power from the ECU if the ECU gets powered via relay 109.

HTH

 

[wonneber]

RH,

7 volts is not enough to run the computer in the car.
You have to find where the voltage is lost.
Jumping power to the solenoid may not put power to the computer.
Relay 109 (mentioned) may be the problem. (I think the grey ones are know to go bad)
Corroded electrical connection in a fuse, the 109 relay, loose wire nut in the fuse box under the hood could do it.
If you are not familiar with electrical work it may be cheaper to get help then guess by trial & error.

alright, gonna try to 'splain this the best I can

00 Beetle, wouldnt start, engine would spin over, but not start,

checked around, the selenoid on the injection pump had low voltage, ~7 volts.

I run jumper wire from battery to selenoid and engine will crank

I find fuse in box thats hot on crank and run and run jumper wire from there to selenoid.