Speaking of air, when the factory VGT turbo has been replaced with a fixed turbo, there are also codes that come up. The P0299 is set when the computer doesn't see the amount of boost it expects to. This usually happens at low rpms when the fixed turbo hasn't started to spool.
- P0299: EP Turbo/Supercharger Underboost EP actual is less than commanded.
In addition to the P0299 code, a P0046 can also be set. The P0046 is set when the VGT solenoid is disconnected.
- P0046: VGT Solenoid Turbo/supercharger boost control solenoid circuit range/performance open circuit, control circuit short to voltage, control circuit short to ground, faulty solenoid, faulty PCM.
These are some of the most common DTCs that show up on the 2003-07 6.0L Powerstroke engines. There are many other codes that can pop up from time to time, but these are the usual suspects. Be sure and take the vehicle in as soon as possible to have it checked out, before driving too many miles and finding out the little problem that turned the light on is now a big problem that costs a bunch to repair.