E46 M3 SMG code 24 (from an Autel scan tool)

[snaponbob]

I have not hooked up INPA yet as I just returned from a two Time Trials at Heartland Motorsports park. Since I have got the car up and running after building it, I have sorted various small issues. I have attended two SCCA TNiA as well as a local event at RPM in Iowa. Everything has been working fine until yesterday. After a few how laps the transmission started acting up. At first it was putting itself into 5th gear after upshifts from 3rd to 4th and then after a few downshifts to to 3rd. after a while, it became more apparent and finally lit the cog wheel. My Autel scanner showed code 024 Sequential Manual Gearbox (SMG), position sensor selection angle. Then upshifts from 3rd to 4th were being ignore, or skip to 5th, or just not shift. I started lifting the throttle on the 3-4 upshift and that helped SOME. Cog wheel lit again.

Can the position sensor sensor be tested installed or uninstalled? In normal driving none of this happens. After a couple hot laps at racing speeds it starts to happen, so possibly temperature related.

Any thoughts or suggestions? Tomorrow I will hook up INPA.

[eacmen]

Didn’t have issues like you describe but I learned to do an smg bleed and adaptation each morning of a track event. Otherwise weird things happen.

That being said the gear position sensor is a common failure and wouldn’t be surprised if you needed to replace it.

[snaponbob]

Didn’t have issues like you describe but I learned to do an smg bleed and adaptation each morning of a track event. Otherwise weird things happen.

That being said the gear position sensor is a common failure and wouldn’t be surprised if you needed to replace it.

Interesting. I may try that. But, at $6-700 for a new gear position sensor, I was hoping to test the sensor to see what is wrong with it. If there IS a test, I can check mine as well as any used one I might find.

BTW, my Autel MX808 will do all those procedures.

[eacmen]

Interesting. I may try that. But, at $6-700 for a new gear position sensor, I was hoping to test the sensor to see what is wrong with it. If there IS a test, I can check mine as well as any used one I might find.

BTW, my Autel MX808 will do all those procedures.

Not sure on a test.

I would troll parts for sale on forums and facebook. Can usually get used gps for $50. I end up grabbing entire used smg setups from manual swaps and picking through the parts and keeping the good parts for spares.

[domibln]

You need to read the SMG error memory with Inpa or ISTA-D. Only official BMW software supports all SMG specific error codes and service functions.

Gear position sensor failures are usually not temperature related. It is rather the electro-hydraulic components that tend to cause problems at higher temperatures, as the hydraulic oil then has a higher viscosity and may pass seals more easily (--> internal or external leakage).

[snaponbob]

You need to read the SMG error memory with Inpa or ISTA-D. Only official BMW software supports all SMG specific error codes and service functions.

Gear position sensor failures are usually not temperature related. It is rather the electro-hydraulic components that tend to cause problems at higher temperatures, as the hydraulic oil then has a higher viscosity and may pass seals more easily (--> internal or external leakage).

I did use INPA to read temps and other parameters. Eventually, MLR and Burkhart both indicated that the likely problem was the gear position sensor. Burkhart had a better price and could ship immediately. So, 4 days later I had it, installed it, and test drove the car.

First observation was that NONE of the DIY videos suggested unbolting the transmission crossmember. I did and it was a snap. Why? No issues accessing the two Allen screws. Second observation was that there were subtle differences in how the system responded to shifter input. My car has an actual CSL transmission computer from a 2002 Euro CSL car and the DME was remapped to better accommodate the CSL software as well as adjusting the DME to accept the 4.10 final drive (and that is a real thing -- made a real difference even before the sensor failed).

We'll find out for sure July 6 as I will be at an SCCA TNiA.

[bosundave]

I had the same issue, Because of the bad, high heat placement of our SMG stuff, the Gear Position Sensor (GPS) gets finicky over time from constant heat exposure. Mine acted up only in the heat of South Florida Summer, and would be OK when cool..unti it just got so annoying. It would default to havinf gears only R, 2, 5, and 6. Then after a day or two would work again.
Loose the IPNA. The fault code explanations are all in GERMAN, even on so called English versions. Get ISTA-D Rheingold. It will work with Win 10. Buy a brand NEW $900 (ouch!!!!) GPS. a $200 used one will not last. I have spent $400 finding that out. Face Palm.

You will have to run a tranny adaptation (probably) after installing a new GPS. Resist the temptation to do ANYTHING else in the tranny. Too many ways to screw up. Changing the GPS is not hard. I bought a set of long thin SAE allen 3/8 drive. They didn't have any metric, but one of the SAE fit perfectly. Buy the METRIC set if they have it, of course at Home Depot.
I never did bleed my clutch system. Don't do things for the sake of doing them when messing with software...I found out.

I want to be BURIED in my M3 IF I die. So, I plan on relocating my SMG to under the hood in the Smugglers Compartment (ex ABS) My 2005 box is empty and waiting for my SMG. They make KITS to do this. A guy on one of the forums sells them.

Buy the heavier, more efficient fluid from BURKHART in Germany. I will probably buy this refurb kit for my aging SMG.
https://burkhart-engineering.com/en/...-incl-csl-bmw/

Check your 1) Drive shaft guibo, center bearing and CV joint where it attaches to the diff. I would DEFINTLEY replace your rear diff cover with w new one. Worn diff bushings really screw up our SMG's. Its time. Just get a brand new cover for $150 which comes with new bushings. I used a BMW gasket and Permatex sealer made for Diff gear oil. We replace it with OUT dropping the rear sub frame.

Still have your OEM half axles?? The grease has turned in to a nasty thin liquid. Open the rubber boot and clean with one to two cans of brake clean. Re pack with RED LINE Synthetic CV grease. Cheap on Amazon. 100 times better than OEM BMW grease. Its red iin color and super sticky. I pack 30ML syringes(no needle) with it. I use the syringe to INJECT the grease.
You can use a STRONG zip tie instead of a hose clamp to re-seal the boot.

[snaponbob]

Burkhart sells the GPS for 600euro ($640). Cheapest anywhere. Cost about $100 for DHL to Missouri in 4 days.

MLREng sells the relocation kit (braided lines and harness extension. Not sure if they sell a mount, but that can be fabricated.