tiffytiff25
Junior Member
- Joined
- Oct 9, 2025
- Posts
- 29
- Reaction score
- 15
- Location
- Pacific NW
- Ram Year
- 2013
- Engine
- PentaStar 3.6
Hey guys, so I need your help!!! Im
About driven to my wits end trying to figure out exactly what’s causing this problem.
Sorry for the essay, but I’ve searched the forums and seen that a lot of other ppl have had problems with codes related to the 3-way coolant valve, but no one has been able to find a definitive solution….so hopefully this thread helps them as well.
So before I start, I know my problem is not the 3-way coolant valve itself. I’ve already replaced it twice lol.
I think my problem is 100% electrical, just something small that’s causing a ton of chaos.
So a bit of history….
For a long time now, whenever I’d press the fob, a random door wouldn’t lock/unlock…whatever I’d just gotten used to it.
Also, usually after driving for a while, I think after hitting a small bump or pothole, the “service electronic braking” message would flash, in the dash, and my traction control light would come on. But then on the next drive cycle, the light would be gone and everything back to normal.
And more and more frequently now, after shutting off my truck, the rear brake lights would stay on. If I’d mash the pedal down, or even very slightly pull it up, they’d turn off. I’ve also been told that sometimes when driving they’d even be on (without my foot on the brake pedal).
Whatever….was minor inconveniences, but didn’t seem to be causing any damage so I was just living with it.
That was until…..one night white driving normally my truck all of a sudden went into limp mode. The codes that came up were:
P0653 - sensor reference voltage b circuit high
P2681 - engine coolant bypass valve control circuit / open
P0572 - brake switch a circuit low
I saw on this forum that someone suggested just unplugging the connector to the 3-way valve would stop the limp mode, so I did that just so I could get home. At that point I parked the truck.
I then changed the 3-way coolant valve and the brake pedal switch.
I also noticed that one of the ground straps that went from the back of the passenger side valve cover, down to the passenger side heat shield under the truck was corroded and broken. So I replaced it with a brand new one, and this time attached it to a good point on the frame rail under the truck.
I also added another ground strap from one of the alternator mounting bolts to a part of the body under the hood on the advice of a friend.
After this, the 3-way coolant valve problems went away for a while, and even the door locks seemed to be working better — not 100%, but failing less. The brake light problems was still happening, so I replaced the brake pedal switch again, but still the same problem. The “service electronic braking system” light also hasn’t seemed to come back, even after. Highway drive, and a bumpy drive.
Although, pretty much right away, even after clearing codes, p26a7 and p2681 (both codes related to the 3-way coolant valve) kept popping up. I replaced the valve again, but the codes kept coming back. It was driving fine, and the heat was fine, and the temperatures were normal, so I thought I’d take a couple days off from dealing with it.
I thought it was good enough for now until……the truck went into limp mode again and had the same additional coolant valve sensor b, etc coded come up again.
I don’t think my problem is faulty actuators, or the wheel speed sensors themselves, because there’s no pattern to it…it’s completely random. And the brake pedal switch I’ve replaced twice already with a factory one lol.
So what could it be? Still a grounding problem? I don’t even know where to go from here? I can’t keep replacing parts lol
About driven to my wits end trying to figure out exactly what’s causing this problem.
Sorry for the essay, but I’ve searched the forums and seen that a lot of other ppl have had problems with codes related to the 3-way coolant valve, but no one has been able to find a definitive solution….so hopefully this thread helps them as well.
So before I start, I know my problem is not the 3-way coolant valve itself. I’ve already replaced it twice lol.
I think my problem is 100% electrical, just something small that’s causing a ton of chaos.
So a bit of history….
For a long time now, whenever I’d press the fob, a random door wouldn’t lock/unlock…whatever I’d just gotten used to it.
Also, usually after driving for a while, I think after hitting a small bump or pothole, the “service electronic braking” message would flash, in the dash, and my traction control light would come on. But then on the next drive cycle, the light would be gone and everything back to normal.
And more and more frequently now, after shutting off my truck, the rear brake lights would stay on. If I’d mash the pedal down, or even very slightly pull it up, they’d turn off. I’ve also been told that sometimes when driving they’d even be on (without my foot on the brake pedal).
Whatever….was minor inconveniences, but didn’t seem to be causing any damage so I was just living with it.
That was until…..one night white driving normally my truck all of a sudden went into limp mode. The codes that came up were:
P0653 - sensor reference voltage b circuit high
P2681 - engine coolant bypass valve control circuit / open
P0572 - brake switch a circuit low
I saw on this forum that someone suggested just unplugging the connector to the 3-way valve would stop the limp mode, so I did that just so I could get home. At that point I parked the truck.
I then changed the 3-way coolant valve and the brake pedal switch.
I also noticed that one of the ground straps that went from the back of the passenger side valve cover, down to the passenger side heat shield under the truck was corroded and broken. So I replaced it with a brand new one, and this time attached it to a good point on the frame rail under the truck.
I also added another ground strap from one of the alternator mounting bolts to a part of the body under the hood on the advice of a friend.
After this, the 3-way coolant valve problems went away for a while, and even the door locks seemed to be working better — not 100%, but failing less. The brake light problems was still happening, so I replaced the brake pedal switch again, but still the same problem. The “service electronic braking system” light also hasn’t seemed to come back, even after. Highway drive, and a bumpy drive.
Although, pretty much right away, even after clearing codes, p26a7 and p2681 (both codes related to the 3-way coolant valve) kept popping up. I replaced the valve again, but the codes kept coming back. It was driving fine, and the heat was fine, and the temperatures were normal, so I thought I’d take a couple days off from dealing with it.
I thought it was good enough for now until……the truck went into limp mode again and had the same additional coolant valve sensor b, etc coded come up again.
I don’t think my problem is faulty actuators, or the wheel speed sensors themselves, because there’s no pattern to it…it’s completely random. And the brake pedal switch I’ve replaced twice already with a factory one lol.
So what could it be? Still a grounding problem? I don’t even know where to go from here? I can’t keep replacing parts lol
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