“Switch Chain Grip“....stalling out at lights

[liam821]

Who is responding to whom at this point? Lol.

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I think the take away is any number of sensors, wiring, coding, switches, fuel, or mechanical problems can cause our cars to stall randomly. lol

[lemoose]

His car is factory 6mt.

Lol my blunder! Was getting too used to this issue arising in smg swaps. I guess this probably points to a clutch switch or wiring issue then

[terra]

I had a no crank/no start issue that was caused by a failure of the now NLA brown switch.
I have been making do with the non-M switch which means no cruise control.
Recently I had a stalling condition at traffic lights and found on a Schwaben reader, code 50 DME: switch chain, frictional connection.
This is the intake cam sensor failing.
Just something for you to bear in mind.

Switch chain grip is always either the clutch sensor or gear recognition sensor. Cam sensor has nothing to do with it whatsoever. In your case it’s because you’re using the non-M switch.

[FBloggs]

Switch chain grip is always either the clutch sensor or gear recognition sensor. Cam sensor has nothing to do with it whatsoever. In your case it’s because you’re using the non-M switch.

yes.
I was thinking of his stalling problem.
I recently resolved a stalling problem by replacing the intake cam sensor. So in the offchance his clutch module did not fail, he could look at the intake cam sensor. He has recently replaced the intake cam sensor. Which makes my input irrelevant.

[lapoune]

How is the gear selector switch used by the ecu? Would it cause the same issues as a defective clutch switch? I keep getting a code 80 switch chain grip and difficult starts/hesitation, but my clutch switch works fine in inpa. Any ideas?

[terra]

How is the gear selector switch used by the ecu? Would it cause the same issues as a defective clutch switch? I keep getting a code 80 switch chain grip and difficult starts/hesitation, but my clutch switch works fine in inpa. Any ideas?

Their wired in series so the dme can’t tell which one is bad. If your clutch pedal still seems to work in INPA, then your gear recognition switch might be stuck closed.

[antknee]

Their wired in series so the dme can’t tell which one is bad. If your clutch pedal still seems to work in INPA, then your gear recognition switch might be stuck closed.

i tried googling gear recognition switch and keep coming back to an SMG related part.

Would you happen to know which part number this is?

[terra]

i tried googling gear recognition switch and keep coming back to an SMG related part.

Would you happen to know which part number this is?

23142229113

Transmission would have to be removed to replace it unfortunately. Personally if it were my car, I'd bypass the switch and code it out rather than bothering with replacement (if it is indeed failed)

[antknee]

23142229113

Transmission would have to be removed to replace it unfortunately. Personally if it were my car, I'd bypass the switch and code it out rather than bothering with replacement (if it is indeed failed)

FML lol. Thanks for all the feedback....super informative. I spoke to my buddy who has guided me through this as well (he's done a bunch of SMG swaps).....and said coding out would prob be the best option....although he did mention its not super straight forward (whatever that means since i know nothing about coding).

[lapoune]

23142229113

Transmission would have to be removed to replace it unfortunately. Personally if it were my car, I'd bypass the switch and code it out rather than bothering with replacement (if it is indeed failed)

Do you know what the ecu does with the gear info? My Z3MC doesn't have one at all, so curious why the m3 has one with same engine, mss54 etc.

[mrgizmo04]

Side note that, to swap out a non working GPS with a working one, you need a 22mm and that can be swapped out without dropping the tranny.

If you have a fresh smg unit with a blind plug that needs to be tapped to be able to accept a GPS, that's a different story.

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[sapote]

Do you know what the ecu does with the gear info? My Z3MC doesn't have one at all, so curious why the m3 has one with same engine, mss54 etc.

GPS tells DME if the gear is engaged or neutral, and DME uses the info to activate the idle speed control and over-rev fuel cut off, or not. SMG does not need the GPS as the computer already knows the gear status.

[terra]

Do you know what the ecu does with the gear info? My Z3MC doesn't have one at all, so curious why the m3 has one with same engine, mss54 etc.

Basically tells the DME it's not in gear if either the gear lever is in neutral or clutch is depressed. With the Z3M, BMW implemented some code to basically have the car assume it's in neutral if the switch reads as closed but the car isn't moving. Why they didn't decide to code it that way on all S54 cars (and like pretty much all other BMWs in general), I have no idea. The DME tweaks I recommend SMG owners to do instead of tapping the threads more or less replicates the Z3M functionality.

Side note that, to swap out a non working GPS with a working one, you need a 22mm and that can be swapped out without dropping the tranny.

If you have a fresh smg unit with a blind plug that needs to be tapped to be able to accept a GPS, that's a different story.

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Good to know. I remember it looking quite tight back there and I could have sworn on the old forum people had to drop the tranny. Regardless, I think I'll just bypass the sensor if mine ever fails.

[mrgizmo04]

Good to know. I remember it looking quite tight back there and I could have sworn on the old forum people had to drop the tranny. Regardless, I think I'll just bypass the sensor if mine ever fails.

Forgot to clarify, there is room there only for a box/open end, def no room for socket/ratchet. Tranny doesn't even need to be lowered. Just some notes for anyone else who stubles on the thread and wants to take that route.

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[mr.nelsonlin]

Hi Guys, same issue here with my 6MT swap, I put in 61319122701 switch for my car which is the euro switch, I coded out my EWS since the 701 switch does not support the clutch interlock. After putting in the switch, my cruise control is working now, no more fault code “switch chain grip” what so ever.
The stalling issue seem to be gone 90%, and the car idles much more smoothly than before. But every now and then the car still stalls at the red light stop, completely same symptom. Oh BTW my DME software coded to ditch the need of GPS sensor. Any idea what cause the stalling problem ?