Engine/Transmission (1998.5 - 2002) Overboost code, stock engine

[Turbo Trucker]

My check engine light is on and I have a couple codes. One is an overboost code, but the only mod I have is a K&N filter. Everything else is stock all the way to the tailpipe. Also I'm getting a throttle position sensor code for too little voltage.



If I have a bad TPS than is it possible that it's getting an overboost code because it thinks it's not at full throttle but it's getting full boost? I noticed it feels like it's defueling right around 2700-2800 rpm.



I guess I'll replace the TPS and see what it does. I imagine this would also affect power/ mileage.

 

[StakeMan]

It could be a stuck wastegate or a bad MAP sensor. I didn't see gauges listed in your sig. If you do, what is your max boost psi?

 

[Huff N Puff]

Its a chicken or egg situation

Cause the PCM use one or the other to test each other,if you have a scan tool you can look a freeze frame. Its a snapshot of all the data at the time of the failure. If RPM TPS are consistant and MAP is of than its probably a MAP failure or a waste gate failure. Hope this helps Merv

 

[Turbo Trucker]

Quick update, I found the TPS sensor was reading a low of . 3 volts. Someone posted that it will cause an error below . 4 Anyway the sensor has elongated holes so you can adjust it a little, I got the low up to . 5



Now I know it's in the proper range, . 5 - 3. 5 V so if I still have a MAP code, I'm going to replace the MAP sensor.

 

[Turbo Trucker]

Ok I figured it out. I have a bad wastegate actuator, it's leaking air and doesn't open.