Gearbox/Starting Problems - Need ideas!

[heinkeljb]

So what was wrong?

Would be nice to know....

John

[lalli_d1]

So what was wrong?

Would be nice to know....

John

+1

[mac999]

Various CAN bus errors had to be cleared due to the faulty underseat relay/fusebox causing havoc and the transmission also required adaption due to the gear position motor and gear angle sensor being previously removed.

[tolsen]

Various CAN bus errors had to be cleared due to the faulty underseat relay/fusebox causing havoc and the transmission also required adaption due to the gear position motor and gear angle sensor being previously removed.

Thanks for taking time to report back.

There is no CAN wire connected to underseat relay and fusebox. Having dozens of CAN errors is actually quite common especially on my 2002 Cabrio. No issue as long as they are not current.
Gear change motor removal is safe enough, just do not turn on ignition. Also safe enough to remove gear position sensor, again leaving ignition off.
Fault codes related to either will inhibit start or gear changes. Fitting fully working gear components and deleting fault codes is sometimes enough to sort it out but I have also had to resort to gear change adaptation.

[Elboor]

Sorry here's an overall picture on the whole thing:

So car initially had 3 bars on the dash, was unable to start the engine/crank it - occasionaly it would turn over but I couldn't get it to do this all the time. I suspect now this is where the broken wires/connectors on the fusebox/relay under pass seat was at fault.

Started tearing the car apart, looking for common issues (chafed wires, dodgey position sensor, actuator, gear select motor, tried rocking the car back and forth to get it into gear) - Nothing. Decided we wanted to have a look at the gear selector/stick, removed both seats only to stumble upon the fuse/relay box under passenger seat.

Bodge wiring exposed (functional but not pretty - printed out all ECU pin outs and relay/fuse outputs and tested them all) all tested fine - NOTE: Only performed a continuity test, looking back a proper test with current would have been smarter (as mentioned by tolsen) but luckily got away with it. Upon further inspection it was clear the fuse/relay box itself was toast with corroded/missing pins and mostly around plug 1 (hs1??).

New underseat fuse/relay installed - Car looked to have been fixed. Fuel pump would kick in with ignition and all other sorts of noises. Wouldn't always allow me to start the car because it never found NEUTRAL correctly, but with persistance and moving the gears about (R/N/Gear up/Gear down) the gearbox would occasionly wake up and activate gears and allowed me to return car into NEUTRAL for a start.

Success!!

** Gear select motor, gear position sensor, clutch actuator had all been removed to inspect and test where possible - Ignition was on/off all the time to see if we could get it to start, im guessing this screwed with the car ultimately and needed adaptation and various faults clearing because of this! **

This is where I come here looking for help because it only worked if I hard reset the car by disconnecting the battery!

Read my initial post and you'll get the idea.

mac999 turns up and plugs in his stupid expensive merc box in and gets to work. I leave him for a bit and come back to the car running.

Sacreblue. What sorcery is this?

All done and dusted. Still yet to take it for a road test, MOT had to be postponed too!

[lalli_d1]

did say get the codes read would help a alot

[mottofreee]

Wheels suspended?
Trust+(system similar to ESP) into action and:
- Limits engine speed at 1500rpm
- Bring the gearbox in 0

[10:45PM]

Wheels suspended?
Trust+(system similar to ESP) into action and:
- Limits engine speed at 1500rpm
- Bring the gearbox in 0

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