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2016 S550e - Charge port flashing red light / Check Engine Light / P0D9C(00) Code
I’m looking for help troubleshooting a Check Engine Light/Charge Port problem.
Yesterday when I started my car, I noticed the Check Engine Light was on. The car drove fine in both EV and gas modes. Then, when I got home, I tried to plug in the charger and got a flashing red light at the port. I unplugged and used my OBDII scanner to check the codes, and I found several (mostly archived), but the ones that stood out were the active P0D9C(00) and an archived P0D9D on the Powertrain Control Unit (PTCU). The active code indicated it's the one that requested the Check Engine Light (MIL), and as both are related to the “Battery Charger Coupler Temperature Sensor”, I'm assuming they're also the reason for the flashing light on the charge port.
Researching online brought up nothing, and I saw some posts on Reddit about finding troubleshooting procedures in Xentry. I wanted to reach out here first to see if anyone has had or seen this before I invest in a Xentry set up.
I’m looking for help troubleshooting a Check Engine Light/Charge Port problem.
Yesterday when I started my car, I noticed the Check Engine Light was on. The car drove fine in both EV and gas modes. Then, when I got home, I tried to plug in the charger and got a flashing red light at the port. I unplugged and used my OBDII scanner to check the codes, and I found several (mostly archived), but the ones that stood out were the active P0D9C(00) and an archived P0D9D on the Powertrain Control Unit (PTCU). The active code indicated it's the one that requested the Check Engine Light (MIL), and as both are related to the “Battery Charger Coupler Temperature Sensor”, I'm assuming they're also the reason for the flashing light on the charge port.
Researching online brought up nothing, and I saw some posts on Reddit about finding troubleshooting procedures in Xentry. I wanted to reach out here first to see if anyone has had or seen this before I invest in a Xentry set up.
I tried searching TSBs, but nothing came up. Right now, I'm looking for any info on how to troubleshoot this issue. Internet search for the code brings up very little info, and nothing specific for the W222. So, I can't find any way to test it and worse, I can't even find out which part is causing the error (Though I suspect its the charge port itself).
I read that Xentry has testing procedures, so that's why I brought it was going to try that, but as it's not simple/quick process to get my hands on it, I was hoping if someone here already has Xentry, they can try to look it up (I'm not sure if that's even how Xentry works).
I tried searching TSBs, but nothing came up. Right now, I'm looking for any info on how to troubleshoot this issue. Internet search for the code brings up very little info, and nothing specific for the W222. So, I can't find any way to test it and worse, I can't even find out which part is causing the error (Though I suspect its the charge port itself).
I read that Xentry has testing procedures, so that's why I brought it was going to try that, but as it's not simple/quick process to get my hands on it, I was hoping if someone here already has Xentry, they can try to look it up (I'm not sure if that's even how Xentry works).
You already bought it? If so, there is simulation function in XENTRY for testing purposes.
Sorry, what I was trying to say is "that's why I brought it up".
I see, don't worry about it, as for that code as you mentioned you can't find it anywhere online, did you happen to test the condition of the high voltage battery? I wonder if you can see the charge level through the workshop menu.
Looks like the battery is okay, here's what I get from the service menu after starting the car
You can see the check engine light is still on, but car drives & recharges fine from the engine, but will not accept a charge from the port. I suspect all either a bad connection or a bad temp sensor on the port. I cleaned up the inside connection with some contact cleaner, but can't get to the other side without taking bumper off.
Looks like the battery is okay, here's what I get from the service menu after starting the car
You can see the check engine light is still on, but car drives & recharges fine from the engine, but will not accept a charge from the port. I suspect all either a bad connection or a bad temp sensor on the port. I cleaned up the inside connection with some contact cleaner, but can't get to the other side without taking bumper off.
I am not sure what is the normal voltage for the high voltage battery but vehicle is in accessory mode though, you mean the check engine light is still there when the engine is started?
Yeah, since I can't charge it thru the port, I've been hovering around 10% to 20%. I can confirm it charges as I put it in 'Charge' mode yesterday and it charged the battery using the engine to 75%. Driving it today, I went all EV most of the day, and got it down to 10% which is when I took the picture.
I don't think anything is wrong with battery/drive train. I am now convinced it's the charge port itself that's bad, but need to confirm before I get myself a new one as they're not cheap and taking off the rear bumper is a chore.
Do you have access to Xentry? I need to see if there's a test process for the port.
Last edited by Badgertastic; May 11, 2025 at 02:59 PM.
Yeah, since I can't charge it thru the port, I've been hovering around 10% to 20%. I can confirm it charges as I put it in 'Charge' mode yesterday and it got to 75%. Driving it in EV mode today and I went all EV most of the day, and got it down to 10% which is when I took the picture.
I don't think anything is wrong with battery/drive train. I am now convinced it's the charge port itself that's bad, but need to confirm before I get myself a new one as they're not cheap and taking off the rear bumper is a chore.
Do you have access to Xentry? I need to see if there's a test process for the port.
I don't actually sorry. I recommend getting a system from Peter, his banner is on top of the forum.
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