Code PO477- What is it & what's it mean?

[slowneasy]

I used the 04. 5 truck yesterday towing the horse trailer and it really felt like crap . Almost dying taking off in 1st up a slight incline and NO power when shifted into the next higher gear while very high EGT's.

I just checked the ignition codes on the truck and came up with PO477 which is "Exhaust Pressure Control Valve Low". Does anyone know what it all means, parts involved and what needs to be done to fix it?



No mods on truck other than gauges, pacbrake, air compressor and AirDog.



Thanks guys.

 

[p-Bar]

What kind of boost numbers are you running? It does sound like a boost issue. Curious is your A/C working? Their is a solenoid that is run by the ECM that controls the wastegate. check to see if the rubber hose is cracked or broken, It's on the lower side of the turbo, crawl under the truck.

 

[slowneasy]

p-bar-

thanks for the reply. Boost numbers seem okay- anywhere from 22-27 psi depending on the grade I'm pullin', speed, gear etc. All stock so I think that's normal. Isn't ~30psi max for a stocker?



A/C seems to be working okay. I used it yesterday, outside air temp was at least 101˚ and the A/C felt fine on the second blower knob setting.



I'll still check the rubber hose.

 

[p-Bar]

I was curious about the A/C just because I threw a code and it killed the a/c and cooling fan circuit If we can get Bob4X4 to respond he works for a dealer and got me some info to troubleshoot your situation. Yes you are right on the boost. Curious are you sure that PACbrake is all the way open? heard all these brakes hang up.

 

[slowneasy]

p-bar-

that is a good question on the PXBR brake... it is air operated and shuts off when the go pedal is in use. Now that's not to say that it might not be stuck, but I KNOW it works good otherwise 'cuz I used it a bunch coming down the mountain and the Grapevine. So I would have to guess that it isn't sticking or stuck in the closed/closing position. Maybe jelag could help answer this question.