Hey guys,

My car is throwing code 33 (high voltage at the MAF sensor), so I've decided to replace the sensor...I have a haynes manual, but it doesn't give any instructions on how to replace it.

Is it just how it looks? (take off a couple of screws outside the air intake duct, unplug a few wires from the old MAF sensor, put in new MAF, re-hook everything up)

Sorry about the uber noob question lol, but I just want to be sure before I **** something up.

 

That's it, very simple. Disconnect the battery before you do the swap and reconnect after done.

 

Code 33, "MAF high output voltage" can be caused by several things and like all high sensor voltage codes, is often caused by a open ground or sensor circuit. On these older cars wiring issues are to be expected. Your Haynes manual should have a test description of some sort for this code. Mitchell On Demand has the factory test procedure and is available online at your local library. I will try breifly to explain the test procedure.

The tool youll need is a good voltmeter (10 Megaohm/volt). With key on, testing at the MAF connector, you should find 12 volts on the red wire, good ground on the black and black/white wires, 5 volts on the dk grn wire. The blue wire should have 12 volts only for a few moments after the engine is turned off.

The safest way to test ECM grounds is to use the volt scale and look for a steady 0 volts between a good engine ground and the ground being tested. Any voltage you see is volt drop across the ground circuit and shouldnt exceed .2 volts on a sensor ground. The full test procedure goes much further to verify proper circuit function and is worth looking at before replacing an expensive sensor.

As far as replacing the sensor, if I remember right, the OE MAF sensor is attached to the intake air duct with a clamp that must be removed and reinstalled when replacing the sensor. Replacement MAFs may have a removable sensor assembly which attaches to the housing with two torx screws. Replacing it is as easy as unplugging it, removing the screws and swapping sensors. A little vaseline or silicone lube on the o-ring will help when inserting the sensor.

When youre done, you can clear codes by disconnecting the battery for 10 seconds, though this code will correct itself once the repair is done and will drop out of ECM memory after 50 engine starts with no failure.