I have just recently purchased a 2004 Maxima with some issues. First I replaced the timing chain and guides it sounded like a meat grinder. Then about 2 months later the oil pump failed and I had to put an engine in. The car has right at 110,000 miles on it and it is a beautiful car. Now I have a "VDC off" light is on and the car is in limp mode. The 3 codes were for MAF, O2 sensor & IAT.I have cleared the codes and the only one that stays is the MAF. I have check the resistance on the wires from the ECM to the MAF pins, check the battery voltage at the sensor and checked the ground wire to the MAF. Everything is in spec. should I replace the MAF again (only 6 months old) or should there be something else I should do. Will this cause the VDC light to come on or is there still another issue. I have checked the brake fluid, replaced 1 abs sensor and cleaned the others. I see that there is a ecm programming for this vehicle for the VDC light, should I take it to the dealer or is there another test that I can do before that!

What I would do is pull the ECU then open it up.
I would take a multi-meter and test continuity first so they don't try to tell you to buy a new ECU

I went through the rest of the tests from the service manual pinning out the ECU and TCM. It told me to replace the MAF. I replaced the MAF and it took it out of limp mode. The code for the oxygen sensor is active, failed the test so will be ordering it!

You shouldn't have to take it to a sales center unless your trading it or getting recall work done! There may be a pedal trick to reset the ECU as is in the 5.7 gen.
The guides are a common problem in the 6th gen.