Archived What is causing these codes?

[DavidMartin]

Help, Tonight my truck's check engine light came on, initially the truck seemed to run fine, but then it lost significant power, the turbo did not seem to be functioning and then it began to shudder above 2000 RPM. When I checked the codes I initially got P 0234 as the initial problem that caused the light and a subsequent P 0238. When I attempted to clear the codes to see if they would return the same way, only the 0238 returned. But the truck continued to run poorly. The 0234 indicates that there is a problem with the wastegate, I checked the vacuum line and it is intact. Do the wastegates become defective frequently? The truck has only 75K on it and has been running fine, the only thing I have done different with it is tow about 9000 lbs about 35 mi round trip last weekend. The 0238 indicates that there is a high voltage situation with the MAP sensor, what causes this and should the sensor just be replaced or can it be serviced? Any help with this would be greatly appreciated. Thanks

Dave

 

[B.G. Smith]

Do you have a boost gauge on the truck? The 0234 code is "turbo boost limit exceeded". The line on the turbo is a pressure line which sends turbo boost pressure to the wastegate actuator which diverts exhaust gas around the turbine when boost limit is reached, (around 18 to 20 pounds). Since the MAP reads the manifold pressure, if it actually saw the boost go above what the ECM considers normal then it might set a code too. You can move the wastegate lever by pushing on it from the front of engine and from above the intake manifold with a long screwdriver to see if it is stuck. By the way, the turbo should be covered by the 100,000 mile warranty on the engine. bg

 

[DavidMartin]

Unfortunately I don't have a boost gauge, I guess it is time to get those gauges. Much to my dismay I had to take the truck to the dealership, as I am completely booked through the weekend and I need my truck. Hopefully they don't sting me too bad. Thanks for the info.

Dave

 

[Alan Reagan]

If the MAP is malfunctioning, it will indicate that you are exceeding boost pressure. You may get the over/under voltage from the MAP. Sounds like the MAP is toast.



With the MAP malfunctioning, you'll get reduced fueling, etc. MAP is where I would start. Isn't that a warranty item under 75K?

 

[2-ND TIME]

Keep your old parts and if you can measure the resistance on the pins on the old to new maps. MIne all measured about the same. Did it fix the problem (NO)!

 

[DavidMartin]

Well it turns out that the MAP Sensor was toast, took from Friday to Monday to get one, $300. 00 later (Parts and Labor) it's done and running great. Thanks god it was not anything with the turbo. Thanks to everyone who posted.

Dave