Changing the MAF Sensor on an Aston Martin V8 Vantage
DISCLAIMER: As always, follow all safety protocols. Don't undertake this task if you aren't comfortable with it and fully understand it. 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 Anyway, I had a fault code for one of my mass air flow (MAF) sensors, so I figured I'd replace it. The part came quickly from Stuart at VelocityAP and eventually I got around to installing it. I apologize in advance if my pics aren't as good as the ones I usually take. I used my cell phone for the pics and usually I have a Nikon.
The steps below detail the procedure I used for replacing the left-hand (driver's side on US cars) MAF sensor on my 2007 V8 Vantage. The right-hand side MAF sensor should be the same. If you are cleaning your MAF sensors instead of replacing them, the same steps can be followed. See post #8 for information about cleaning a MAF sensor.
Wheel chocks (or similar)
T10 Security Torx Bit
T30 Torx Bit
1/4"-drive Ratchet (or other tool, for torx bits)
22mm Socket w/ Ratchet
About an hour
Quick note on security torx bits: You can buy a set of these for pretty cheap ($5-10) and are worth the investment if you don't have a set already. Normal torx bits are also good to have on hand and are very, very useful for us because Aston Martin uses them all over the car.
Break the lugnuts loose on the front left wheel (driver's side on US cars) using the 22mm socket. Don't take them off, just break them loose so you can remove them once the car is in the air. Breaking lugnuts loose will be extremely difficult once the car is in the air as the wheel will just spin as you apply pressure to the lugnuts.
Get the car on jackstands. Ensure the car is properly supported before continuing. If it's good and stable, put wheel chocks behind the rear wheels to keep the car in place (a section of 2x4 wood can work if you don't have wheel chocks). Then remove the front left wheel - this will give you space to work.
Use the Philips screwdriver, and T30 torx bit to remove the front undertray. Then unfasten the wheel liner so it can be moved out of the way, at least on the front end (closest to the front of the car) or remove the wheel liner entirely.
Step 3b (If you removed the wheel liner entirely, you can skip this step)
I only loosened the front rather than remove it entirely and used the access panel to stick my arm through for the rest of the steps. There is an access panel directly behind the headlight in the wheel liner. Remove the access panel. There are two screw points on the headlight housing that allow you to adjust the headlight beam angle. But that's another job. We're removing the panel so we can put our arm through it.
When you pull the liner back, you can see the MAF sensor sitting there looking all fabulous with its colorful wires:
NOTE: The airbox solenoid in the pic above may not be on your car. These solenoids (one on each airbox) control flaps that open up to allow more airflow. These are the airboxes found on the N400, V8VS, V8VGT, and V8 Vantages that have the Aston Martin Power Pack (which is what I have).
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. Unplugging it can be a pain. If you've got nimble fingers and a small, flat-head screwdriver, give this a shot. 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 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.
With the MAF sensor unbolted and unplugged, you can remove it. 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. Remember that the plug connector clip faces away from you when installed. That's the easiest way to determine which way the MAF sensor should be oriented. Bolt the MAF sensor into place, then plug in the connector.
Reverse what you did in steps 3, then 2, and then 1 to put everything back together. Make sure you properly torque your lugnuts. Then turn the car on and hope nothing went terribly wrong.