Questions and Answers

Mazda 626 MAF And TPS Sensors Q. Vincent, I own a 1995 Mazda 626 2.0 4 cylinder, fuel injection, 49,000 miles. My question is, my mechanic did a diagnostic test and found both the MAF and TPS sensors need replacement. I want to do the work myself. Is it a fairly easy job or should I have the mechanic do it?

I am an engineer so I am pretty good with engines. I also need to know if you know of any web site that has a written text on doing this job or a book that gives a step by step replacement guide. I know I can do this myself, I just need a diagram or something to lead me in the right direction. Any help will be greatly appreciated.

Thank You,
Richie

A. The Mass Air Flow (MAF) sensor is easy to replace.

Removal:

1. Disconnect the MAF sensor connector.
2. Disconnect the Intake air temperature (IAT) sensor connector.
3. Loosen the MAF sensor clamp at the air duct.
4. Remove air cleaner housing upper cover.
5. Remove the four MAF sensor mounting bolts.
6. Remove the MAF sensor from air cleaner housing upper cover.

Installation:

1. To install, reverse order of removal.

Now I'm assuming you have an automatic transmission. If you have a manual transmission, the procedure is different.

You will see a wire clip and two small screws on the MAF connector. DO NOT remove the two screws on the air flow meter. Remove the wire clip from the groove at both sides using a small screwdriver.

Replacing the Throttle Position Sensor (TPS) is a little trickier because it has to be adjusted.

Replacement:

1. Remove the air hose.
2. Disconnect the throttle position sensor connection.
3. Remove the screws.
4. Remove the throttle position sensor.
5. Install the throttle position sensor.
6. Adjust the throttle position sensor output voltage.
7. Install the air hose.

To adjust the TPS, you will need a special service tool called a Breakout Box. This is something I would trust to the dealer since most shops do not have this special service tool.