Transmission Failsafe

[lezmtaylor]

Have had this problem for a while now ,when starting the car and in Park , frequently the trans f/safe warning comes up .
The car battery is 2 years old and is fully charged (Ctec charging when parked). The initial way to make the wng light go out is : switch off ign , remove key, wait for warning to go out and try again. Some times the wng stay out, other times it take numerous times before it stays out.
Is there a wng sensor that is playing up ?
I have just tried slipping the gear shift into neutral before starting  and so far the T W L has not come on.
The warning does not come on when driving the car.

May seem a bit garbled, but have given as much info as possible.

Lez

[henrym3]

Difficult Lez, so many things can cause this really need a scan to hopefully point you in the right direction. Are you starting the car with the ctec still connected or are you disconnecting first. As it isn’t happening when driving i would still lean toward battery problem but really need a scan


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[lezmtaylor]

Hi Henry,
No always removing ctek before starting the car.
Any suggestions for best code reader ?

Lez,

[V8 00USH]

You can't usually scan the gearbox ECU for codes with cheap scanners as they only scan do the engine ECU. Best off trying to find someone with BMW software or a decent commercial scanner like a Snap On etc.

I've had this on mine a couple of times too on startup but nothing has shown when I've scanned it.

[henrym3]

I have one of Foxwell's expensive scanners (hand held) £300+ and it scans the gearbox, been very impressed and not just because I spent that sort of money but in all honesty over the last 4 years had I went and payed for a scan I would probably have spent way more than that plus you have the convenience of the slightest problem then bung the scanner on.

[marti]

Even though you say your battery is only 2 yrs old it can still be a low voltage problem cells do sulphate and die, check the voltage when not started should be around 12.2V or there abouts and when running 13.8V to 14.2V.

[lezmtaylor]

Well, I thought I would try and explain what I have done to cure!! the problem.
On the advise of Henry3 I bought a good code reader ( Autel Maxidiag Elite MD802) , but it did not throw up any fault codes for the Trans Failsafe).
Sod it , so I have now adopted the following start procedure which works every time.

To start : key in ignition, turn to 1st position, select Neutral with trans selection lever (gear stick) and then start car, works every time, NO Trans failsafe on panel.

I know I may be missing something, but this system works everytime, Road speed is fine( had legal limit +60)
so any ideas out there.
Battery is fine, 2years old.
Have just done 2 x 320m trips in last week, no probs.

Lez

[Sky Bear]

Maybe look at popping it into someone who specialises in gearboxes for their take on it.

Gloucester Road gearboxes in Bristol could do you a full dialysis fluid change at the same time which is always a good move with an auto box.

Or if starting in neutral works for you call it character and ignore.

SB

[henrym3]

Feel well guilty now Lez, spending all that money and not getting a fault. Hopefully it will pay for it’s self in the years to come. Not that I’m hoping you’ll get lots of faults. I’ll stop now before I dig the hole any deeper

[lezmtaylor]

No Problems Henry, got another tool to play with and as it does all makes of car Suddenly I am very popular with the younger family members,  can't think why!!

Lez

[V8 00USH]

That will be your transmission position switch at fault then.  Around £250 brand new from BMW. I've recently replaced mine with a used one off an L322 4.4i M62 Range Rover (£65) as it was doing the same thing and eventually came up with the corresponding code stored on the transmission ECU.

[lezmtaylor]

Thanks for that, at least i now know what the problem is , but why no info on the codes?
Where is the switch positioned and is it difficult to replace?

Lez

[henrym3]

https://www.pelicanparts.com/techarticl ... cement.htm

[lezmtaylor]

Many thanks Henry, at least I have the info now printed off and in the ''to do'' File.

Lez