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

[antknee]

I started googling a little deeper in the code…..and there was a thread somewhere (e39 m5 forum) that a slipping/bad clutch could also throw a “switch chain grip” code aka stall at stops. It kind of makes sense to me, but was wondering if there was any validity to it?

[sapote]

I'm trying to understand the logic of why a bad clutch switch would cause the stalling problem.
1. Does the DME increase the idle (to avoid stalling) if it senses the clutch pedal is down? Why does it need to do so?
2. If the clutch switch is closed and GPS is closed (in neutral), the rpm is at minimum (true idling speed)?
3. As both binary states of the switch, open and close, are valid states, then how the DME detects a bad switch? After detected a bad switch, why the DME drops the rpm low to cause stall?
4. Stalling issue is not a driver error (as someone just learns how to drive stick shift)?

[maupineda]

Does anyone have an idea what could cause the car to think the clutch is pressed on all the time? bad sensor or could there be something else?

[deschodt]

Hey all, bumping this thread with similar issues, yet slightly different triggers...

My car (03) was SMG and was already doing this "stall when coming to a stop" on occasion, rarely in normal driving, but more frequently when pulling up at school pickup which requires doing a U turn as you are coming to a stop (extra strain on the idle from both systems).

I then had it converted to manual by SMG_Antone, on this board - who used all factory parts.... Pretty soon thereafter I noticed that the car was still stalling when coming to a stop, but now it was first thing in the morning, down my steep hill that requires strong braking application.. No CEL but the "50 Switch chain" code is present, and always returns very quickly. The car doesn't really do that when fully warm, might "wanna" a couple time as it warms up but generally I see it coming and can catch it.

I checked the clutch switch (the magnetic clip on kind) and it was indeed the wrong part - Antone confirmed BMW superseded that part accidentally, and that was bad. I ordered a new one with the correct # 61319122700 from ECS - what I got was indeed the correct number but FYI it's no longer brown, it's all black now... installed it... Still same results. Stalled at the stop down the hill a couple days after (not immediately after, of course, just to make believe I had it solved ;-)

Bit the bullet and got INPA setup, and after much swearing at the laptop/cable, got it working and confirmed correct operation of the clutch switch in INPA by going to E46 > Engine > MSS54 for S54 > Read Status > Digital 1 > Status Grip Switch. The status was off with the clutch out, and on with the clutch in, all "live" while plugged in so I'm sure. So that new switch gets read properly, not it and apparently not the wiring since it's read by the laptop properly..Cleared all codes while in there, 50 came back.

The other day when the car was still relatively cold - past the hill of idle death - I noticed that if I pressed the brake pedal hard at a stop light, the RPM would drop 2-300... It didn't do that later in the day... Vacuum leak ? sensitive to engine temps ? but then why code 50 ?

So that's where I'm at, what next ? I can clean the ICV - can't hurt but then why the 50 code anyway? Should I replace the gear position switch at the gearbox ? (is that easily reached) Could that alsot rigger this 50 code ? I need to try Cruise control, I never EVER used that so no idea if it works.

Could it be a vacuum leak ? It feels like one, I mean anything is possible especially after an SMG conversion where lots of old rubber boots and lines were disturbed and it's possible one cracked invisibly (not blaming the conversion tech at all), but again, would that trigger a "50 switch chain" code instead of a lean condition ? I think not...
Please advise !!

[shumile.swift]

Hey all, bumping this thread with similar issues, yet slightly different triggers...

My car (03) was SMG and was already doing this "stall when coming to a stop" on occasion, rarely in normal driving, but more frequently when pulling up at school pickup which requires doing a U turn as you are coming to a stop (extra strain on the idle from both systems).

I then had it converted to manual by SMG_Antone, on this board - who used all factory parts.... Pretty soon thereafter I noticed that the car was still stalling when coming to a stop, but now it was first thing in the morning, down my steep hill that requires strong braking application.. No CEL but the "50 Switch chain" code is present, and always returns very quickly. The car doesn't really do that when fully warm, might "wanna" a couple time as it warms up but generally I see it coming and can catch it.

I checked the clutch switch (the magnetic clip on kind) and it was indeed the wrong part - Antone confirmed BMW superseded that part accidentally, and that was bad. I ordered a new one with the correct # 61319122700 from ECS - what I got was indeed the correct number but FYI it's no longer brown, it's all black now... installed it... Still same results. Stalled at the stop down the hill a couple days after (not immediately after, of course, just to make believe I had it solved ;-)

Bit the bullet and got INPA setup, and after much swearing at the laptop/cable, got it working and confirmed correct operation of the clutch switch in INPA by going to E46 > Engine > MSS54 for S54 > Read Status > Digital 1 > Status Grip Switch. The status was off with the clutch out, and on with the clutch in, all "live" while plugged in so I'm sure. So that new switch gets read properly, not it and apparently not the wiring since it's read by the laptop properly..Cleared all codes while in there, 50 came back.

The other day when the car was still relatively cold - past the hill of idle death - I noticed that if I pressed the brake pedal hard at a stop light, the RPM would drop 2-300... It didn't do that later in the day... Vacuum leak ? sensitive to engine temps ? but then why code 50 ?

So that's where I'm at, what next ? I can clean the ICV - can't hurt but then why the 50 code anyway? Should I replace the gear position switch at the gearbox ? (is that easily reached) Could that alsot rigger this 50 code ? I need to try Cruise control, I never EVER used that so no idea if it works.

Could it be a vacuum leak ? It feels like one, I mean anything is possible especially after an SMG conversion where lots of old rubber boots and lines were disturbed and it's possible one cracked invisibly (not blaming the conversion tech at all), but again, would that trigger a "50 switch chain" code instead of a lean condition ? I think not...
Please advise !!

Any luck deschodt? in the same boat basically... its weird... even dudes with OG 6 speeds are having these issues... strange..

[sapote]

1. So that's where I'm at, what next ? I can clean the ICV - can't hurt but then why the 50 code anyway? Should I replace the gear position switch at the gearbox ? (is that easily reached) Could that alsot rigger this 50 code ?
2. Bit the bullet and got INPA setup, and after much swearing at the laptop/cable, got it working and confirmed correct operation of the clutch switch in INPA by going to E46 > Engine > MSS54 for S54 > Read Status > Digital 1 > Status Grip Switch. The status was off with the clutch out, and on with the clutch in, all "live" while plugged in so I'm sure.

1. Yes, because clutch switch and GPS are connected in series, and so the DME has no way to know which one has an open circuit/switch.
2. You should retest the status in INPA again, but this time leave the clutch up, then shift into gear and back to neutral and see if the status change with geared/neutral.

[terra]

Bit the bullet and got INPA setup, and after much swearing at the laptop/cable, got it working and confirmed correct operation of the clutch switch in INPA by going to E46 > Engine > MSS54 for S54 > Read Status > Digital 1 > Status Grip Switch. The status was off with the clutch out, and on with the clutch in, all "live" while plugged in so I'm sure. So that new switch gets read properly, not it and apparently not the wiring since it's read by the laptop properly..Cleared all codes while in there, 50 came back.

To me this suggests you don't have a gear position sensor (i.e clutch switch is wired directly to DME), in which case I would recommend tuning it out of the DME so that it works properly.

[deschodt]

1. Yes, because clutch switch and GPS are connected in series, and so the DME has no way to know which one has an open circuit/switch.
2. You should retest the status in INPA again, but this time leave the clutch up, then shift into gear and back to neutral and see if the status change with geared/neutral.

Thank you all for the follow up - this is driving me bonkers and it's the last code on the car (finally. For now).
I will replace the gearbox switch, it arrived... I will laugh if I find chewed wires. Hopefully this can be done without too much access issues.
I did #2 - clutch pedal action still triggers "status grip switch" ON-OFF (circle turns black/white) on INPA - but "shifting in gear and back to neutral" does nothing at all on that page. None of the displayed values on that screen change.

And from Terra
>To me this suggests you don't have a gear position sensor (i.e clutch switch is wired directly to DME)

Meaning the gear position switch is defective or disconnected, or.... that as a conversion, there isn't one at all ? Will go look for the GPS first and report... I do not know how to tune that out of the DME, unfortunately.

>shumile.swift

Yup same boat. It will stall every morning at hard stops / hard turns, first time it is run in the AM. I heel and toe it now, not great for my wife though. Clearly the DME doesn't compensate for the brake/steering load - unaware. Never happens once the car is warm.

[deschodt]

Ok so after pondering the wise words of Terra and Sapote above, and stumbling on the full SMG conversion thread, it occurred to me maybe the person who converted my car did not even install a GPS on the gearbox (needs a tap - possibly some cabling). I was not even aware that was a possibility. I also noticed I do not have reverse mirror dip anymore nor are my parking sensors active any longer (how observant of me!), so I would not be surprised if the conversion was not total.

So after exploring options, I jumped in the pool:
I found a mention of the the MSS54 tool from the UK (only $24 with foreign exchange - immediate license via email ) which works with my existing K+Dcan cable I was using with INPA (free), and also downloaded the BMWFlash utility.
I loaded my DME with BMWflash as instructed (partial only), made a copy, edited the copy in MSS54 in 2 places:
1) General 2 tab (clutch switch config = 6MT swap without GPS (clutch switch wired direct))
2) main screen check box for "disable requirement for GPS after conversion - maybe both do the same thing - no idea
Saved, loaded in BMWflash and reflashed my car, held my breath for 2 minutes, no problem...

The car started. No lights... Phew!
Erased all codes, changed underwear (hey I reflashed my DME!!) and went for a drive. 50 Switch chain has not come back yet. I won't shout victory because the car is not cold. We'll see tomorrow - first time I' be eager to drop off a kid at school early.
Intimidating? yes, hard? no... Fingers crossed !

Went from clueless to clueless editing DME in one post.

[deschodt]

Report from this AM: No codes.
None ! For the first time ever since I own this car, not one code. Maybe I need to drive longer - give'em a chance ;-). Even the "implausible engine temp" went away (I have some new sensors for that anyway).
On the first "Steep Turn of stall and death" the idle remained at 1100 and no stall... On the first "stop of death" at the bottom of the hill, it did dip the idle to 700 or so and caught it all by itself. Subsequent stops, same. It's not "rock solid" when super cold on those first stops - one of them I thought it may die, but it caught it - did not stall anymore.
And the bleeping 50 switch chain grip whatever appears gone after 2 subsequent code reads. I will report again later in the week to be sure, but this is promising. I will follow with an ICV cleanup to be sure to help.

In other good news for me, it appears Sreten from M539 restorations bought the exact same car as me, so I expect a lot of videos on how to keep fixing it ;-)

[special77]

Report from this AM: No codes.
None ! For the first time ever since I own this car, not one code. Maybe I need to drive longer - give'em a chance ;-). Even the "implausible engine temp" went away (I have some new sensors for that anyway).
On the first "Steep Turn of stall and death" the idle remained at 1100 and no stall... On the first "stop of death" at the bottom of the hill, it did dip the idle to 700 or so and caught it all by itself. Subsequent stops, same. It's not "rock solid" when super cold on those first stops - one of them I thought it may die, but it caught it - did not stall anymore.
And the bleeping 50 switch chain grip whatever appears gone after 2 subsequent code reads. I will report again later in the week to be sure, but this is promising. I will follow with an ICV cleanup to be sure to help.

In other good news for me, it appears Sreten from M539 restorations bought the exact same car as me, so I expect a lot of videos on how to keep fixing it ;-)

Hey any update on if this kept your issue resolved? I think I’m having a similar problem.

[sapote]

So why "Switch Chain Grip" causes engine to stall? I have been asking this question myself for a while, and I think here is the reason: The DME detects wrongly that the car coasting in gear and cut off the fuel injectors; this stalls the engine as it is actually in neutral or clutch is disengaged.

[thomn8r]

My car threw the chain grip code a couple of days ago, which led me here.

I have an '03 that was converted to 6MT last year by a local shop. Mine was the first complete conversion they'd done, so I think there might be some details that were missed. I've had the idle-drop-with-clutch-in problem since Day One, as well as losing the mirror dip and parking sensor functionality. They bumped up the idle speed a bit to counter it, but at times the car is almost undriveable - particularly with the A/C on.

@deschodt (is this the deschodt with the Ghia?) - did you change the clutch switch too, or just the coding?

[sapote]

I've had the idle-drop-with-clutch-in problem since Day One

Step on clutch pedal while coasting in gear?

Solution: either code out the sensor in DME, or install clutch and gear position sensors, wire the signals in series, from GPS to clutch then to DME pin20 of 24pin connector.

[liam821]

Step on clutch pedal while coasting in gear?

Solution: either code out the sensor in DME, or install clutch and gear position sensors, wire the signals in series, from GPS to clutch then to DME pin20 of 24pin connector.

This also was the fix for me. When they did the SMG->6mt swap the shop did not install the clutch switch. I coded out GPS in the DME and added a clutch switch and now it drives completely like stock.