First thing to start with is p0506, start by cleaning the throttle body. That will take care of the p0506. Looking at the data for the p0171 the long term fuel trim is at +18 it should be as close to 0 as possible, LT fuel trim is what your going to keep an eye on. Here are some things I want you to check. Why you are checking these things I want you to monitor LT fuel trims, if they go down or go to 0 your heading in the wright direction. On rare occasions, a SES light may be encountered with a DTC P0171 and no engine performance concerns. Upon inspection, low MAF sensor grams and excessive long term fuel trims may be noted at a hot idle. This may be the result of unmetered air entering the engine due to an air intake leak, air filter concern, or air outlet duct screen damage. Inspect the AIR intake system for rolled connections, cracks, or loose clamps between the MAF sensor and throttle body and repair as necessary.
Inspect the screen that is on the inlet side of the air outlet duct for obvious damage. The air outlet duct is #3 in the artwork below.
If the Long Term Fuel Trim is consistently above 10%, temporarily remove the air filter element, reset the fuel trims, and evaluate the Long Term Fuel Trim. If the Long Term Fuel Trim remains around 0% with the air filter temporarily removed, there is an issue with the air filter that is causing lower than normal MAF readings. To correct this concern, replace the air filter. Also take a fuel sample, check for water or rust. Monitor 02 sensors, should be between 200mv to 800mv and should fluctuate. Unplug the mass air flow sensor when it is running and see if the long term fuel trims change and go to 0, if it does not go to 0 the mass air flow sensor is not the problem. These are just some things to check, try some of these things first and post back. There are more things to check. Lean codes are the hardest to diagnose.
Tuesday, November 25th, 2008 AT 10:02 AM