Intake Installation and P0101 Code

I've had two customers now who ran into the P0101 code with their intake installations. I want to put some info out so that if people get this code, they'll know what to look for.

The code is a MAF Sensor Circuit Malfunction. It is triggered when the MAF readings are out of scale for longer than 8 seconds. While a number of failure modes can generate this code, the times we have been able to replicate it in our shop or have seen it on customer vehicles are based on the following issues:

• Unplugged MAF Sensor resulting in readings by the ECU that are out of range (low).
• Downstream vacuum leaks (Loose T-Bolt Clamps, disconnected valvecover breather or boost control solenoid hose).
• On vehicles that are equipped with one of the first units we sold or with customer installed air diffusers, the diffuser may be loose and requires a few dabs of RTV to secure it into the MAF housing.
• Check intercooler couplers for leaks. The second customer with this issue identified that as the issue.

Depending on the failure mode and duration of runtime with the leak, a P0171 lean at idle code may be thrown by the ECU as well.

If you see this code, it is important to inspect for leaks immediately and avoid driving the vehicle in this condition. If you do need to drive it, at the very least do a quick look under the hood at the hoses to see if anything jumps out at you - this is usually a simple fix due to something being overlooked or not fully connected. If you need to drive the car, stay out of boost and drive it gently to your destination.

Hope this helps anyone who runs into this issue.

Jason
CorkSport

This is why I chose Corksport for my future Intake purchase when they do their next '09 MS3 build set. On top of the problem, with good analysis, and data to back it up, reported promptly to share on the board. Good job.