MAF Sensor Replacement DIY Guide
DISCLAIMER
As always, follow all safety protocols. Don't undertake this task if you aren't comfortable with it, fully understand it, and are capable of completing it. The information provided may be incomplete or inaccurate. You are ultimately responsible for anything you do. Neither Redpants, LLC or myself is responsible or liable for anything that may occur.
I just want to say that this is a 5 or 10 minute job on any other car I've ever worked on. On a V8 Vantage? An hour or so, if you even have the right tools. I think this might’ve been the first job I did on an Aston Martin that made me take a step back and think to myself… “Seriously?”
Needed
MAF Sensors
Floor Jack
Jack stands
T10 Security Torx bit
T30 Torx bit
T40 Torx bit
Ratchets for Torx bits
Tools to remove lug nuts
Philips screwdriver
Swear Jar
About an hour
Before you begin
This job can be done without removing the front undertray or fender liners (Steps 2 and 3), but removing them does give better access and far more visibility so you can see what you’re doing and it’s what I recommend if you’re not familiar with the job. If you do want to leave the fender liner in place, just remove the fasteners around the access panel behind the headlight - pull back the fender liner to put one arm between it and the fender, and put your other arm through the headlight access port.
The MAF sensors are the same on each side of the car, but oriented in a mirrored fashion. This DIY Guide describes the job to replace the MAF sensor with the security tab facing away, which is the more difficult of the two. The other MAF sensor has the security tab facing you so it’s much easier to remove.
Also, sorry for the low-quality pics in this DIY Guide, It’s one of the first ones I ever made, many years ago, and I didn’t have the best camera back then!
Step 1
Break the lug nuts loose on the front wheels. You don’t need to remove them entirely, just one spin will do.
Get the car off the ground, either with a lift or using a jack and jack stands. If you’re using a jack and jack stands, this job can be done with just the front off the ground but I personally always put all four corners on jack stands.
With the car off the ground, you can remove the front wheels.
Step 2
Use the T30 and T40 Torx bits to remove all the fasteners on the front undertray. The bolts are the only thing holding up the undertray - once they're removed, the undertray will fall. So be ready for it!
Step 3
Use the T30 Torx bit and Philips screwdriver to remove the fasteners from the front half of the fender liner, then pull the fender liner down to expose the air box and intake ducting.
The MAF sensor connector is circled in the picture below.
Note: In the picture above, you can see the solenoid found on Power Pack air boxes, located just below the MAF sensor and attached to the airbox with a metal bracket. Read my Information page about the Power Pack if you want to know more.
Step 4
If you’re doing the side with the MAF sensor security tab facing away from you, this is where it gets tricky. The release for the MAF sensor plug faces toward the front of the car, which is horrible in every way. In addition, there's a sliding clip on the plug that prevents it from being released by accident... or on purpose. This is what it looks like:
You can go about this two ways. You can either unbolt the MAF sensor then unplug it, or you can unplug it then unbolt it. Once unplugged, it will be easier to get to the bolt further from you. Since I couldn't see the plug's evil trickery afoot the first time I did this job and didn't realize how devious it was, I gave up trying to disconnect it and instead unbolted the MAF sensor then unplugged it.
To unplug the MAF sensor, the red tab needs to slide up (toward the wires). If you have nimble fingers, use a small flat-headed screw driver to slide the tab. You can try your fingers or fingernails but have your swear jar ready. Once the red tab is slid away (it will not come out) you can squeeze the connector to release it, just like most automotive connectors.
Unbolting the MAF sensor is easier said than done. You're working in a tight space and trying to get a tiny Torx bit into a tiny Torx bolt. To unbolt the MAF sensor, you need a T10 security Torx bit. It looks just like a normal Torx bit, but it has a hole drilled into it. You need this, because for no other reason than to make your life absolutely miserable, Aston Martin decided to use these little turds to bolt in the MAF:
I found out about the security Torx bolts after getting the car torn open and fighting (and failing) to unplug the MAF sensor. And then I had to go across town and buy a set of security Torx bits. All the while, my swear jar kept filling up.
Step 5
With the MAF sensor unbolted and unplugged, you can remove it.
Note: Remember which way the MAF sensor is oriented so the new one is positioned the same way.
There are some very fragile components inside the sensor. In the pic below, you can see my old one (on the left with brown and dirty bits inside) and new one (on the right with shiny bits).
Very carefully put the new MAF sensor in place, orienting it in the same way as the original was positioned. Bolt the MAF sensor into place, then plug in the connector.
Step 6
Button up the car using the reverse process as the steps above.
And that’s it, all done!