Exhaust Pressure Codes
Thread Starter
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Laughing Gas
Joined: Feb 2006
Posts: 947
Likes: 1
Exhaust Pressure Codes
I have two codes that keep coming up when i run ae. p0470-exhaust back pressure sensor circuit malfunction and p0478-exhaust pressure control valve high input. What do these mean and where should i start looking to make these codes not come up anymore. Thanks for any help in leading me in the right direction.
Post Fiend
Joined: Jul 2005
Posts: 14,582
Likes: 12
From: 21791
It sounds to me like your Exhaust Backpressure Sensor is not reading the correct exhaust manifold pressure. There is a tube that extends from the front of the right side manifold upwards along the front of the engine. It terminates at the sensor, which is in front of the HPOP oil reservoir, between that and the serpentine belt. It is very close to the top-most idler pulley. Remove this sensor with a 1" socket, and see if it has buildup on it. Clean it with compressed air or a wire brush. Then remove the other end of that tube with (i think) a 9/16" wrench. Blow through this with compressed air too, or if it is super-clogged, try a purple pipe cleaner (purple is the best-suited for this application). Reassemble and go for a joy-ride, and see if that code comes up again.
