CEL, diagnose NPP exhaust valve
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Joined: Nov 2020
Posts: 60
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From: Pittsboro NC
CEL, diagnose NPP exhaust valve
At the end of a HPDE track day at VIR the check engine light came on. That evening I drove the car on the street for approximately 25 miles and the CEL went off.
Took it for scan next morning and got the check NPP valve readout. Cleared the fault and drove it on the track for the day. CEL did not return.
Questions, why did it come on in the first place and go out by itself and should I take it to the dealer?
Took it for scan next morning and got the check NPP valve readout. Cleared the fault and drove it on the track for the day. CEL did not return.
Questions, why did it come on in the first place and go out by itself and should I take it to the dealer?
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Joined: Dec 2020
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From: Reality
I and others have had this happen. It seems when this car is pushed harder especially depending on what mods you may have or just OEM it stresses ( GM's tight perimeters ) the intake and mostly the exhaust more and being the car seems rich from the manufacture it will throw these lights in a higher stress environment than any form of street driving. Normal for this car it seems but nothing to worry about. It seems it doesn’t take much to trigger the CEL from the whole exhaust.
I wouldn’t take it to the dealer unless the light stays on and the exhaust is still stock.
I wouldn’t take it to the dealer unless the light stays on and the exhaust is still stock.
Last edited by NoMatter; Jul 1, 2022 at 04:47 PM.
