2016 Buick Envision Premium P305E and D error cods

[cyber_guy]

Anyone ever had issues with either of these codes? Started one day with car acting like it had a dead battery which sounded like it wanted to start but just stays clicking. It’s not the starter kind of clicking. Check engine light came on so I ran my diagnostic scanner and it showed P305E and P305D. A jump start gets it going. At times it takes a few tries to grab even right after driving around for 40 mins. It’s a hit and miss to grab on the first try. Lights on dash will flicker. Battery is good and healthy. Both Autozone and Orilies came back with all test being good. No check engine light anymore but my dash shows a symbol I’m not familiar with and hadn’t seen before. Looks like a light beam with arrows pointing left and right at the top in a downward curve. Kind of looks like the high beam lights. It comes and goes. I cleaned battery posts but even then there was no corrosion. I did try doing a parasitic drain test and it showed a constant 5 amps draw when in the off position. Any help is greatly appreciated.

 

[cyber_guy]

Anyone ever had issues with either of these codes? Started one day with car acting like it had a dead battery which sounded like it wanted to start but just stays clicking. It’s not the starter kind of clicking. Check engine light came on so I ran my diagnostic scanner and it showed P305E and P305D. A jump start gets it going. At times it takes a few tries to grab even right after driving around for 40 mins. It’s a hit and miss to grab on the first try. Lights on dash will flicker. Battery is good and healthy. Both Autozone and Orilies came back with all test being good. No check engine light anymore but my dash shows a symbol I’m not familiar with and hadn’t seen before. Looks like a light beam with arrows pointing left and right at the top in a downward curve. Kind of looks like the high beam lights. It comes and goes. I cleaned battery posts but even then there was no corrosion. I did try doing a parasitic drain test and it showed a constant 5 amps draw when in the off position. Any help is greatly appreciated.

Just sharing some additional info as I learn more while troubleshooting in hopes it helps others. Still having issues. Dealership appointment set for tomorrow. But feel I'm making progress. Thanks to others in this form I was able to get my hands on the free online troubleshooting guide for my vehicle. Searching up those codes pointed me to either a faulty power connection/ground or malfunctioning DC/DC transformer converter. So using the guide I started troubleshooting the battery once again. After researching that the hand held battery testers don't test deeper issues like cranking power and the likes. Did a parasitic drain test on the battery and found it was reading 0.6 amps when it should be 0.3 or .4. So figured there was excess draining. Started pulling fuses and it went back down to 0.3 after pulling the one fuses that controls the DC/DC transformer so will replace that too.

 

[cyber_guy]

Just sharing some additional info as I learn more while troubleshooting in hopes it helps others. Still having issues. Dealership appointment set for tomorrow. But feel I'm making progress. Thanks to others in this form I was able to get my hands on the free online troubleshooting guide for my vehicle. Searching up those codes pointed me to either a faulty power connection/ground or malfunctioning DC/DC transformer converter. So using the guide I started troubleshooting the battery once again. After researching that the hand held battery testers don't test deeper issues like cranking power and the likes. Did a parasitic drain test on the battery and found it was reading 0.6 amps when it should be 0.3 or .4. So figured there was excess draining. Started pulling fuses and it went back down to 0.3 after pulling the one fuses that controls the DC/DC transformer so will replace that too.

Update: Today I took off the battery and took it to Autozone to have them charge it and test it correctly. Even though the battery hand held tester they had said it was good. It actually returned as a bad battery when they did the full test while it was off in the store. Charged to 84% but turned out the cranking health was bad so got a new battery. I also picked up an new DC/DC converter for $70 from my local dealer and swapped these 2 out and all is good now.

 

[HotZ28]

I have never heard of a DC/DC convertor?

 

[2021 Envision Essence]

Neither have I. What is it and WHERE is it?

 

[cyber_guy]

Neither have I. What is it and WHERE is it?

Apparently my vehicle has a DC/AC converter which I can see where that one would be used for as my center counsel in the back seats has a plug for 120AC power. The DC/DC one from what I learned is used to pretty much manage the power for what looks to be most of the electrical components in the center counsel and it affects the cranking up of the vehicle. I am not sure what it does but seeing the battery already is DC I'm guessing this one maybe drops it down to like 5V of DC or it takes it up a notch. Seeing I had both a bad battery and while doing the parasitic drain test when I pulled the fuse controlling this module it went to normal which kind of ties back to the error code reading it was a higher voltage being returned as a potential issues. I added some pictures hoping it helps. More than willing to help anyone out if they too have similar issues. I am just sharing at a high-level assuming others would like to know.

 

[cyber_guy]

Apparently my vehicle has a DC/AC converter which I can see where that one would be used for as my center counsel in the back seats has a plug for 120AC power. The DC/DC one from what I learned is used to pretty much manage the power for what looks to be most of the electrical components in the center counsel and it affects the cranking up of the vehicle. I am not sure what it does but seeing the battery already is DC I'm guessing this one maybe drops it down to like 5V of DC or it takes it up a notch. Seeing I had both a bad battery and while doing the parasitic drain test when I pulled the fuse controlling this module it went to normal which kind of ties back to the error code reading it was a higher voltage being returned as a potential issues. I added some pictures hoping it helps. More than willing to help anyone out if they too have similar issues. I am just sharing at a high-level assuming others would like to know.

Not sure why it's not letting me upload more than one image. Here is another in case it did not show it.

 

[KevinBailey58]

Update: Today I took off the battery and took it to Autozone to have them charge it and test it correctly. Even though the battery hand held tester they had said it was good. It actually returned as a bad battery when they did the full test while it was off in the store. Charged to 84% but turned out the cranking health was bad so got a new battery. I also picked up a new DC/DC converter for $70 from my local dealer and swapped these 2 out and all is good now.

Hi Cyber guy,
I have the exact same problem with my 2017 Envision. Where is the DC/DC converter located? Is it in the center council or under the dash? What are the basic steps you did to replace.
Thanks for the help!

 

[Curious1!]

I’m having g the similar issue with my 2017 Envision. Please share where that DC/DC is.

 

[DoItAgain]

I’m having g the similar issue with my 2017 Envision. Please share where that DC/DC is.

I think it's located on the passenger side under the dash. but I am having a hard time getting to it. How did you get to yours?