Intermittent P0791 code caused by Charging system?
#1
09-25-2023, 07:28 PM
Intermittent P0791 code caused by Charging system?
Hi,
I have a 2007 Mazda 6 2.3L. Owned since new and has been pretty fantastic. Except a few of years ago the transmission went (AT light came on the highway, and once it got where it was going shifting wasn't happening all too well in the city). Took it to the dealer here and they first flushed and basic transmission service. Then they determined I needed a new transmission. The first step added a whole lot of expense I'd rather not go through again, so here I am posting!!! Having said that, the original transmission had a weird shift from time to time (usually occurring with oncoming traffic yikes) and the new transmission drove better than when the car was new...
Fast forward to a couple of weeks ago I had left on the key to charge my phone, came back in a couple of hours and the battery was dead. Of note; I have had dead batteries before, and it doesn't seem to take much to kill them. I got a boost and everything was fine. It was a 5 hour highway drive home with no issues.
The next day and the car started fine, drove two blocks - then the engine light and AT light came on at a stop sign. Barely made it through the intersection (no power transfer/hard shifting), pulled over and plugged my code reader in (purchased after the last diagnosis!). P0791 P2707 P0733 P0735 and B1318. I turned the car off, waited 30 seconds then restarted. All the check engine/AT lights went away and the car was driving with no issues again. Weird.
A couple of days later and the same things happens, minus the P0733 code. Restart and it all goes away. It has happened a couple more times, sometimes only with the P0791 code.
Transmission fluid is fine in appearance, smell and level.
I have done quite a bit of reading on this subject now, and what I am really wondering is; is there a possibility my alternator or charging system is causing this somehow? I have also read a lot of headaches regarding finding the right sensor to replace (if the TSS is what the problem is) and all things considered I don't really have the time, energy or tools/place to muck about...but I'm leary the shop will easily resort to the ol -replace transmission thing again.
Any help is appreciated!
I have a 2007 Mazda 6 2.3L. Owned since new and has been pretty fantastic. Except a few of years ago the transmission went (AT light came on the highway, and once it got where it was going shifting wasn't happening all too well in the city). Took it to the dealer here and they first flushed and basic transmission service. Then they determined I needed a new transmission. The first step added a whole lot of expense I'd rather not go through again, so here I am posting!!! Having said that, the original transmission had a weird shift from time to time (usually occurring with oncoming traffic yikes) and the new transmission drove better than when the car was new...
Fast forward to a couple of weeks ago I had left on the key to charge my phone, came back in a couple of hours and the battery was dead. Of note; I have had dead batteries before, and it doesn't seem to take much to kill them. I got a boost and everything was fine. It was a 5 hour highway drive home with no issues.
The next day and the car started fine, drove two blocks - then the engine light and AT light came on at a stop sign. Barely made it through the intersection (no power transfer/hard shifting), pulled over and plugged my code reader in (purchased after the last diagnosis!). P0791 P2707 P0733 P0735 and B1318. I turned the car off, waited 30 seconds then restarted. All the check engine/AT lights went away and the car was driving with no issues again. Weird.
A couple of days later and the same things happens, minus the P0733 code. Restart and it all goes away. It has happened a couple more times, sometimes only with the P0791 code.
Transmission fluid is fine in appearance, smell and level.
I have done quite a bit of reading on this subject now, and what I am really wondering is; is there a possibility my alternator or charging system is causing this somehow? I have also read a lot of headaches regarding finding the right sensor to replace (if the TSS is what the problem is) and all things considered I don't really have the time, energy or tools/place to muck about...but I'm leary the shop will easily resort to the ol -replace transmission thing again.
Any help is appreciated!
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iamcollin
Mazda 323,Mazda 626 & Mazda 929
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04-16-2012 05:18 PM