When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have a 2011 Grand Sport. I had the steering wheel position sensor issue that I fixed with a bi-direction scanner and re-centered the wheel (it was reading 360* instead of 0*, likely the prior owner when installing a cam something got messed up).
Since I bought the car, I’ve also had issue with the driver door. Sometimes the interior button won’t work to open the door, and when this happens, the window is partly down like when exiting the car. I use the manual lever but then the window doesn’t re-index when I close the door. Then I’ll be driving and it will randomly re-index and the interior button will work again.
The code I’ve gotten a few times is B3849, which seems to indicate a ground issue. I’ve cleaned the grounds in the engine bay, cleaned the driver exterior door pad and di-electric greased it. Would my next test be to take off the interior door panel and check the interior door switch connections and module connection (I hear it’s in the door panel)?
Last edited by TheRose86; Aug 3, 2025 at 09:11 AM.
A B3849 is a ground issue but it’s a “short to ground” issue on the signal circuit in the Driver Door Module so cleaning engine grounds or cleaning the door pad won’t fix this…do you have any electrical diagnostic experience beyond changing a fuse ??…if not I would seek out an auto electric shop in your area…you have to know what sets that trouble code before trying to diagnose it.
You may have a “short to ground” on either exterior or interior door switch from the DDM circuit 5881 or 5882…dark blue or brown wire…this may also be a bad switch or door module.
A B3849 is a ground issue but it’s a “short to ground” issue on the signal circuit in the Driver Door Module so cleaning engine grounds or cleaning the door pad won’t fix this…do you have any electrical diagnostic experience beyond changing a fuse ??…if not I would seek out an auto electric shop in your area…you have to know what sets that trouble code before trying to diagnose it.
Thanks for the reply. I’ve done electrical work in the past on House and auto, but not in depth diagnosis. I ordered new interior door switches as one of them on the passenger side specifically is busted. So I’ll start with that, they were cheap enough. The problem isn’t persistent consistently, so there’s something loose or shorting out or something I would think.
You may have a “short to ground” on either exterior or interior door switch from the DDM circuit 5881 or 5882…dark blue or brown wire…this may also be a bad switch or door module.
I think I’m gonna start with the interior button switches, and the connector harness in the door panel. Give those a good cleaning, dielectric grease and see what happens after that.
With your scan tool you should be able to observe the inputs as shown in this flow chart…you don’t need to worry about cleaning and dielectric grease for now.
If you don’t know how to check for a short to ground…both ends of the connectors (Door module and Door Switch) on that circuit need to be isolated and you use an ohm meter…watch the video.
With your scan tool you should be able to observe the inputs as shown in this flow chart…you don’t need to worry about cleaning and dielectric grease for now.
I used the tool to check both the interior and exterior door handle active/inactive. And they both worked properly. So I couldn’t get them to mess up in that regard. I will go through the rest of the steps as well though. Thanks for sharing this.
Last edited by TheRose86; Aug 3, 2025 at 12:12 PM.
I needed to replace the interior passenger door switch as it was busted, so I ordered to pack and replace both. The driver door is still having intermittent issues where it just sometimes will not open for the inside, and today it also would not open from the outside.
I decided to experiment a hit and took the bezel off of the door button. When I did those the door seemed to work every time. I put the bezel back on and noticed that the button would not fully depress or return to its starting position. I wonder if this is the issue. The computer reads the signal in an intermittent state (see video below):
Well, that wasn’t it. Error still persists. I hear signal being sent when I press both interior and exterior switches.
I guess now it’s down to tracing wires to see where the short is. The fuse for the driver door switches seems to be in the passenger footwell. Would I need to pull that BCM to see the pins on the back and follow the wiring?
I have no idea what testing has been done but have you tried unlocking the door on the "OUTPUT " side with the scan tool ??...that bypasses all the inputs...you should hear a “click” coming from the BCM when doing this driver door unlatch…I don't know where in the flowchart you are now but if it says check the signal circuit BOTH ends of that circuit have to be disconnected...door switch and Driver Door Module...disconnect the module and switch and with a test light connected to battery POWER touch the test light to the brown wire (terminal C)...if the test light illuminates you have a short to ground...if you have a bare wire the test light will find a ground through that bare wire and the test light will illuminate...this isn't a fuse issue so just try to read the wiring diagram...this is just for an interior switch issue.
I have no idea what testing has been done but have you tried unlocking the door on the "OUTPUT " side with the scan tool ??...that bypasses all the inputs...you should hear a “click” coming from the BCM when doing this driver door unlatch…I don't know where in the flowchart you are now but if it says check the signal circuit BOTH ends of that circuit have to be disconnected...door switch and Driver Door Module...disconnect the module and switch and with a test light connected to battery POWER touch the test light to the brown wire (terminal C)...if the test light illuminates you have a short to ground...if you have a bare wire the test light will find a ground through that bare wire and the test light will illuminate...this isn't a fuse issue so just try to read the wiring diagram...this is just for an interior switch issue.
Thanks for the response. I’ll take the door panel off and check the module connection. Then I’ll disconnect the door switch and run it again with the scan tool.
When I originally started having this problem, I took off the driver door pad, cleaned it with contact cleaner, put it back together, etc. But I didn’t think to try, which is so stupid and just an oversight, is just switching the passenger pad for the driver pad. Took the two minutes to do that, and so far it is opened and closed every single time. So maybe the issue is in the switch. I will keep running this way until it messes up.
B3849 code and solution?
