Hi everyone,

Very sad to write this but my Mini is pretty sick. It failed to start and I’m trying to figure out why. I'm going to try to be as detailed as possible about what happened and what I did so far. A couple of days before it completely died, I had one or two instances where it wouldn’t start on the first attempt: no cranking sound at all. I didn’t think much of it and assumed I hadn’t fully turned the key. After that, it progressively got worse and eventually stopped starting altogether. Roadside assistance tried to jump-start it, but that failed. There was no sound whatsoever. I had to tow it home.

This what I so far had checked:

Battery & Basic Checks

• Battery resting voltage: ~12.65V
• Voltage drops to ~11V while attempting to start
• Fuel pump primes
• Windows, fans, lights all work normally

So I’m not suspecting a weak battery.

Starter Circuit Testing

I checked voltage at the starter:

• 12V at the main positive terminal
• Good ground at the motor casing (12V)
• Voltage drops slightly (~11.5V) during crank attempts

I also checked the trigger wire when attempting to start:

• 12V at the trigger wire when disconnected from the solenoid
• 0V at the trigger wire when connected to the solenoid during crank (this seems odd?)

Starter Bench Testing

I removed the starter and tested it outside the car:

• Jumped it directly using the car’s battery
• Starter engages and spins normally
• I see about 11V at the trigger wire while the starter is engaged

To double-check, I reconnected the starter to the car using extension cables and triggered it directly from the battery and it worked. So for sure it is properly energized on the car, but I already knew this from the earlier voltage measurements. However, it does not crank when using the car’s trigger wires.

Summary of Observations

• Battery appears healthy enough.
• Starter motor works when triggered directly from battery.
• Car sends 12V to trigger wire when disconnected while attempting to crank
• Trigger wire shows 0V when connected to solenoid during crank. Is this normal?
• Starter will crank when manually jumped, but not using vehicle’s trigger circuit.

At this point I’m trying to determine whether this is:

• A bad starter solenoid?
• A wiring issue in the trigger circuit?
• High resistance somewhere in the control circuit?

Any input would be much appreciated. I'm trying to figure this myself before I get a professional involved. Forgot to mention, I checked fuses F24, F6 and F5 which from what I see in the wiring diagrams are part of the electronic immobilizer system and all are fine. Also while testing the starter when it was still living in the car, it would engage for a split of a second. I should also add that I tried this from Parked and Neutral.

 

Just found this thread about the ignition switch that seems eerily similar to what I’m experiencing: https://www.northamericanmotoring.co...on-switch.html

 

I assume you tried to start in PARK, did you try in NEUTRAL? If it works, I would guess the Sensor/Switch that tells the car the transmission is in PARK may be bad or out of adjustment.

Best of luck.

Motor On!

 

Thanks! Yes, from park or neutral. I'm looking into the inhibit start switch now as well. Because the car does randomly crank, I'm thinking the ingnition switch is the more likely culprit.

 

could be a ground. the one in the engine bay near the motor mount is a good one to check

 

I checked this one and the battery's negative terminal ground. Looked like everything was grounded ok but I sanded the connections just in case. I'm able to jump start the motor using the battery just not the actual car's trigger cable and I have 0V at this wire when attempting to crank. Hopefully it's the ignition switch.

 

Confirmed that my ignition switch has a high resistance (4-6 ohms) between pins #5 and #8 in the crank position. Those pins close the starter trigger circuit and should have 0 ohms. I will be getting a new switch and starter (because why not) tomorrow.

 

sounds right to me. let us know that it worked

 

Mini is back from the dead and running again! Turned out to be the ignition switch (I installed a new Vemo unit). Seeing 12V at the starter trigger wire when it wasn’t connected to the solenoid initially made me think the starter itself was bad. Since I had already removed the original starter for bench testing, I went ahead and installed a refurbished Bosch unit while I was in there. A couple of notes for anyone doing this job: despite what the Bentley manual says, you do not have to remove the exhaust manifold to replace the starter. There’s also no need to remove the wheel to access the lower bolt. The whole job can be done from above after removing the heat shields.

Hopefully this helps someone chasing a similar no-crank issue. Thanks for all the replies!

 

bet that feels good. nice work Sir