SL/R231: Won't go into Park
Thread Starter
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Joined: Feb 2025
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Won't go into Park
Recently, I’ve encountered an issue with my car (2013 R231) where I’m unable to shift into Park (P). The first time, I noticed this after pulling into my garage; pressing the Park button did nothing, though I could shift into Reverse (R). Turning off the ignition while in Drive (D) and restarting the car seemed to reset the system, allowing me to shift into Park. The issue didn’t recur for several days, so I didn’t think much of it. However, it happened again yesterday, and this time I couldn’t shift into Reverse either. After turning the car off and on twice, I was able to shift into Park. This issue is becoming more frequent.
After some research, I read that the problem could be related to a faulty auxiliary battery or low/dirty transmission fluid, though I doubt it’s the fluid since it was replaced about 2,000 miles ago. Has anyone experienced a similar issue, and if so, what was the cause and fix?
After some research, I read that the problem could be related to a faulty auxiliary battery or low/dirty transmission fluid, though I doubt it’s the fluid since it was replaced about 2,000 miles ago. Has anyone experienced a similar issue, and if so, what was the cause and fix?
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Joined: Feb 2021
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From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
Recently, I’ve encountered an issue with my car (2013 R231) where I’m unable to shift into Park (P). The first time, I noticed this after pulling into my garage; pressing the Park button did nothing, though I could shift into Reverse (R). Turning off the ignition while in Drive (D) and restarting the car seemed to reset the system, allowing me to shift into Park. The issue didn’t recur for several days, so I didn’t think much of it. However, it happened again yesterday, and this time I couldn’t shift into Reverse either. After turning the car off and on twice, I was able to shift into Park. This issue is becoming more frequent.
After some research, I read that the problem could be related to a faulty auxiliary battery or low/dirty transmission fluid, though I doubt it’s the fluid since it was replaced about 2,000 miles ago. Has anyone experienced a similar issue, and if so, what was the cause and fix?
After some research, I read that the problem could be related to a faulty auxiliary battery or low/dirty transmission fluid, though I doubt it’s the fluid since it was replaced about 2,000 miles ago. Has anyone experienced a similar issue, and if so, what was the cause and fix?
Definitely check the Auxiliary battery, this is fairly typical behavior when it gets weak. It won’t display a dash warning until it’s really bad….
Other possibility is ISM. But check battery first.
Good Luck.
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Joined: Feb 2014
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sl55
This happened to me once after I pumped the brake pedal hard to "brake hold" while at a stop light.
The car wouldn't go into Park, so I turned off and opened the driver door and it went into Park.
I took out the Aux battery to replace thinking it was the culprit but the battery tested fine. So, I stuck it back into the car and it has been fine since.
I think I may have been too hard on the brake pedal and probably got some switch stuck in the pedal temporarily. I haven't used the Brake Hold function since due to fear of it and it has been fine.
The car wouldn't go into Park, so I turned off and opened the driver door and it went into Park.
I took out the Aux battery to replace thinking it was the culprit but the battery tested fine. So, I stuck it back into the car and it has been fine since.
I think I may have been too hard on the brake pedal and probably got some switch stuck in the pedal temporarily. I haven't used the Brake Hold function since due to fear of it and it has been fine.
Thread Starter
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I bought the car used, so I have no idea if it's been replaced. Mileage is around 58,000 miles. I have a battery conditioner, so maybe I'll give that a try. Thanks.
Thread Starter
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I was hoping this issue would be resolved after the battery conditioner showed green, but that wasn't the case. It happened again yesterday. One more thing I noticed is that when the car won't go into Park, if I open the door, it will go into Park automatically. However, I couldn't put it into drive or reverse until the ignition is turned off and back on. Has anyone encountered a similar situation?
Super Member
Joined: Oct 2012
Posts: 538
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From: Hollywood, CA
W209, W124
There are optical couplers that read gear position in the shifter. When they get cold solder joints you get issues like this but I don’t remember them being connected to door opening.
there is also a plastic piece in shifter that breaks that sticks it in Park.
I would read up on both issues and see if they sound similar. I think W220 or 221 and maybe 215 have similar issues.
there is also a plastic piece in shifter that breaks that sticks it in Park.
I would read up on both issues and see if they sound similar. I think W220 or 221 and maybe 215 have similar issues.
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From: DFW
SL63
An easy fix might be to remove all power as a hard reset. There is probably a certain process to power down that I have seen in other threads. Has any advised on a system scan?
Maybe some codes are being prompted.
Maybe some codes are being prompted.
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My money is on the auxiliary battery. You need to check the date on the battery. My 2013 SL550 batteries were dated **/12, and I replaced both with MB batteries in 2018. The auxiliary battery controls the shifter and the hard top.If it turns out to be the shifter it's easy enough to replace. I'd start with checking the date on the battery. In the R231 the system monitors the auxiliary battery, so you should see a dash warning if it's low. If not then possibly the shifter, If I was going in to replace the shifter I'd do both.
Thor
Thor
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From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
If you’re a DIYer then check codes. if you don’t have a code reader, get a Launch, it’s cheap and better than nothing. Just don’t code with it.
If you know someone (or a shop) with XENTRY, have them record the codes, clear it, and when/if it does it again then read the codes. You can also check Aux. Battery thru XENTRY.
XENTRY will show the errors in the charging system for a bad AUX battery. I wouldn’t rely just on the dash light. I’ve seen many out of spec. Aux batteries that aren’t weak enough to trigger the light but weak enough to cause electrical gremlins and show up in the LINE-BUS section of XENTRY.. Shifters can be a problem since they get liquid from drinks or detailers get sloppy and get dirt or cleaning products or dust/dirt in the shifters by blowing air into them.
The shifters can be cleaned (if contamination is the issue) but you need to remove them to do it properly.
Like all things internet, you’ll get 100 different answers.
Don’t throw parts at this thing. You’ll get buried. If you do throw parts at it, start with the easy stuff first. Like a battery, (and checking the date as THORGOD suggested) and then worry about more advanced replacement of parts after you get the code reader or XENTRY.
Good Luck.
If you know someone (or a shop) with XENTRY, have them record the codes, clear it, and when/if it does it again then read the codes. You can also check Aux. Battery thru XENTRY.
XENTRY will show the errors in the charging system for a bad AUX battery. I wouldn’t rely just on the dash light. I’ve seen many out of spec. Aux batteries that aren’t weak enough to trigger the light but weak enough to cause electrical gremlins and show up in the LINE-BUS section of XENTRY.. Shifters can be a problem since they get liquid from drinks or detailers get sloppy and get dirt or cleaning products or dust/dirt in the shifters by blowing air into them.
The shifters can be cleaned (if contamination is the issue) but you need to remove them to do it properly.
Like all things internet, you’ll get 100 different answers.
Don’t throw parts at this thing. You’ll get buried. If you do throw parts at it, start with the easy stuff first. Like a battery, (and checking the date as THORGOD suggested) and then worry about more advanced replacement of parts after you get the code reader or XENTRY.
Good Luck.
Last edited by crconsulting; Jul 31, 2025 at 10:01 AM.
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From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
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SL 400
If your car won’t go into park simply open the drivers door with the car running and it will auto go into park. Until you are able to fix the issue that feature will have you covered and you will never be stuck in drive.
