GM Volt Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
362 Posts
Discussion Starter #1
Hi Guys,

I've decided I need to replace my OBCM (On Board Charging Module). I'm going to buy a used part to replace the defective part. I understand my Volt may need reprogramming for it to operate correctly. I want to do this myself instead of paying the Chevy dealer. What I think I need is to buy the MDI interface adapter for my PC laptop and pay $55 for Service Programming Only for a 2 day access to the GM TIS service. Does this sound right or am I missing some steps? Thanks

-Eric
 

·
Registered
Joined
·
238 Posts
Here's the link with information on GM's Service Information Subscriptions:

https://www.acdelcotds.com/acdelco/action/subscribehome

How did you conclude it's the OBCM that's bad in your car? Do you have the Shop Repair Manuals and tried the troubleshooting steps outlined there? I have the manuals and will be happy to help in any way I can, just PM me.
 

·
Registered
Joined
·
1,788 Posts
Make sure you purchase the correct OBCM for your model year! One from a different model year may NOT work.
 

·
Registered
Joined
·
362 Posts
Discussion Starter #5
Thanks for linking my previous post. I found a salvage lot in Nashville that has the OBCM for a 2011 for $150. They told me this particular VOLT was not involved in a collision on the front right, as the OBCM is susceptible to damage in front end collisions. For this price, I am not out too much for an incorrect diagnosis. That said, I am fairly confident the OBCM is causing the malfunction.

My CEL is always on and I am showing DTMs P1ECE, P0D4A, P0D5B, and the 12V battery is not charging while plugged in and charging HV. In order for the HV battery to charge, I need to remove the 40A fuse from engine compartment (#44) for a minute or two. I think this removes 12V battery power to OBCM and resets the fault. Doing this allows the car to charge, but the 12V is still not being charged. My biggest concern is if there is a need to reprogram or reset something which requires a trip to the dealer or me subscribing to the TIS system for two days. Maybe someone knows for sure, or I will find out when I replace the component.

Thanks

-Eric
 

·
Registered
Joined
·
2,336 Posts
Once you get the Lear 3.3kW High Voltage Charger replaced on your Volt, coolant refilled and then reprogrammed if necessary try repeating the following test if you can:

With the Volt OFF and 12V AGM connected, begin a charge by plugging in your EVSE. After a couple of min, check the DC Voltage between B+ and chassis ground. It should indicate @13VDC. Lift the negative cable off of the 12V AGM removing it from the circuit. Your Volt should continue charging uninterrupted and there should continue to be @13VDC present between B+ and chassis ground. At least this is the way my Gen1 is behaving...
 

·
Registered
Joined
·
330 Posts
Here's hoping this fixes your 12 volt charging issue.

Keep us posted!
 

·
Registered
Joined
·
362 Posts
Discussion Starter #8
Hi Guys, I finally replaced my on board charge module (OBCM) for my 2011 Volt. I bought a used OBCM from the salvage yard in Tennessee that I mentioned earlier. It was $160 and no core charge. I am happy to say replacing the OBCM fixed all of my problems. The original problem was the 12V battery was not being charged while the HV was charging. Then I got a MIL with a bunch of DTM....

P0D4A
P0D5B
P1ECE

Finally my Volt would not charge on L1 120V, even though it would still charge on my L2. After replacing the OBCM, my 12V was charging when plugged in, with 13.35V on my 12V battery. The MIL turned off by itself, I did not need to clear codes with my scan tool, and there were no DTM. Finally, my Volt would charge on L1 120V as well as L2.

I replaced the OBCM with out removing the front bumper. I don't know, but I am going to guess the proper way is to remove the front bumper. The OBCM is literally wedged into a bulge in the back side of the right front turn signal lamp housing. I had to unbolt the turn signal housing and remove the OBCM and housing together as a pair, and of course install the new OBCM and turn signal housing paired up. I managed to scratch the front of the turn signal lens but it doesn't bother me too much. Thankfully I did not need to re-program anything on my Volt. I made sure the donor vehicle was a 2011 too.

BTW, I took a bunch of tear down pictures of the old OBCM. Unfortunately I was unable to visibly identify the malfunction. The bottom PCB (there are two) is literally glued into the bottom of the cast aluminum housing, it would not come out no matter how hard I pried. I did pry off all of the iron ferrite shells that make up the planar transformers. Quite interesting, but I think it's too weird to be practical IMAO. I'll share the pics of anyone is interested.

-Eric in Georgia (used to be Texas) 2011 Volt #1819


-Eric
 

·
Registered
Joined
·
2,336 Posts
I replaced the OBCM with out removing the front bumper. I don't know, but I am going to guess the proper way is to remove the front bumper.
-Eric
This is amazing to me that you could do this w/o removing the bumper!

I wasn't even able to change my turn signals to LED without dropping the bumper on my Gen1 first.

Glad to hear you got this sorted on the super cheap since $160 was a steal for the Drive Motor Battery Charger.

How did you get around the Drive Motor Generator Power Inverter Module Cooling System Draining and Filling procedure required in the service manual when this part gets replaced?
 

·
Registered
Joined
·
362 Posts
Discussion Starter #10
This is amazing to me that you could do this w/o removing the bumper!

I wasn't even able to change my turn signals to LED without dropping the bumper on my Gen1 first.

Glad to hear you got this sorted on the super cheap since $160 was a steal for the Drive Motor Battery Charger.

How did you get around the Drive Motor Generator Power Inverter Module Cooling System Draining and Filling procedure required in the service manual when this part gets replaced?
I just collected the spilt fluid from the hoses, and there was not much since I plugged the hoses when I removed the old OBCM. After installing the new module, i plugged in the EVSE which ran the cooling pump, the filled up the bottle with the collected fluid. It filled the bottle to the top then I attached the cap. Seems to be working fine still so I think there were no trapped air pockets.

I am curious, when you changed to LED turn signal did you just change the bulb or replace the entire lamp housing. Without removing the bumper, if one changes the lamp housing, the OBCM would need to be removed with the lamp housing as the two parts are interlocked. However it's super easy to just replace the turn signal bulb. It just requires removal of the FL inner fender liner.
 
1 - 10 of 10 Posts
Top