TexAndy
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This thread is awesome. Was able to at least rule out my low pressure switch as a problem.
Symptoms: Truck flashes Hwy as normal on startup. Attempts to operate when pressure reaches 120 (or when I jumper pins A and B on that circuit). PCU in cab makes an operatey type noise and then I hear a quick elephant noise from the little rubber duckbill things as the quick spurt of air parts the rubber lips (was able to film it on my smart phone to tell that was what was making the noise), then the 5 lights on the ECU start flashing. When the low air switch is disconnected, it won't even do this self test.
As far as I can tell, there's no axle air seal leak. Or if there is, it's so slight as to be unnoticeable. At least, I can't see, hear, or feel any air escaping out of the little spring-loaded axle vent caps. What's the best way to tell if I have such a leak? I may just not know what to look at/for.
My wheel valves don't appear to be leaking, but I haven't really submerge tested them, yet.
The dana pdf people linked here indicates 5 lights is an electronic issue. So what is my next likely culprit? PCU? Another poster earlier indicated that his problem was bad solenoid(s) on the PCU.
Any thoughts to move me forward without just buying parts would be most appreciated.
Edited to add: Passenger front tire had a two piece rim o-ring seal leak a month ago. Had that fixed and from about 5 weeks ago to yesterday, it didn't leak a single psi with the CTIS wheel valve disconnected and just a regular valve stem core in it. Yesterday, I took the valve stem core out and hooked the ctis wheel valve back up and the tire was completely deflated, today. Didn't hear or see any air escaping from the wheel valve or any connections to it, but that is clearly a leak source. Not sure if that would cause the symptoms I'm seeing.
Symptoms: Truck flashes Hwy as normal on startup. Attempts to operate when pressure reaches 120 (or when I jumper pins A and B on that circuit). PCU in cab makes an operatey type noise and then I hear a quick elephant noise from the little rubber duckbill things as the quick spurt of air parts the rubber lips (was able to film it on my smart phone to tell that was what was making the noise), then the 5 lights on the ECU start flashing. When the low air switch is disconnected, it won't even do this self test.
As far as I can tell, there's no axle air seal leak. Or if there is, it's so slight as to be unnoticeable. At least, I can't see, hear, or feel any air escaping out of the little spring-loaded axle vent caps. What's the best way to tell if I have such a leak? I may just not know what to look at/for.
My wheel valves don't appear to be leaking, but I haven't really submerge tested them, yet.
The dana pdf people linked here indicates 5 lights is an electronic issue. So what is my next likely culprit? PCU? Another poster earlier indicated that his problem was bad solenoid(s) on the PCU.
Any thoughts to move me forward without just buying parts would be most appreciated.
Edited to add: Passenger front tire had a two piece rim o-ring seal leak a month ago. Had that fixed and from about 5 weeks ago to yesterday, it didn't leak a single psi with the CTIS wheel valve disconnected and just a regular valve stem core in it. Yesterday, I took the valve stem core out and hooked the ctis wheel valve back up and the tire was completely deflated, today. Didn't hear or see any air escaping from the wheel valve or any connections to it, but that is clearly a leak source. Not sure if that would cause the symptoms I'm seeing.
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