I am interested in cars and do my own repairs where I can. I like to share any knowledge I have to help other people where possible.
This is a guide on how to change or clean the MAF (Mass Air Flow) sensor on Opel/Vauxhall Vivaro, Renault Trafic and Nissan Primastar Vans. If you have a Vivaro, Primastar, or Trafic van and have no power at low RPM, general rough running, and have the check engine light illuminated on the dashboard, there are several things that you need to rule out to track down and solve the problem.
Changing or cleaning the MAF sensor can often solve your running problems, so read this guide to find out how to do it. These vans are all the same van, made at the same factory with a different badge on the front, so this guide applies to all three.
Before buying a new MAF sensor, try cleaning it to see if that helps. It's always worth a go and will cost you very little—just a few minutes and a can of electrical contact cleaner. If cleaning it doesn't help, then changing it could be the next step, but go for the cheaper option first!
So What Exactly Does the MAF Sensor Do?
The MAF (mass airflow) sensor basically measures the amount of air that is going into the engine. It then feeds this information to the ECU, which decides how much fuel it's going to then deliver to the engine. As engines run on fuel mixed with air, you can see that if the MAF is faulty or dirty and giving an incorrect reading, it can have a pretty major effect on how the engine runs.
The most common complaint with these vans seems to be that they sometimes are low on power—especially below 2500 RPM—and sometimes won't rev properly.
The best thing to do is connect your vehicle to a diagnostics machine and get the codes. If the code returns back with a MAF fault, then clean it or change it. Some people go through a trial-and-error method of replacing different bits and hoping this solves the problem. I can't recommend doing this, but if you are going to, then the MAF is a good starting point as it's cheap, easy to replace, and is often the cause of a lot of problems.
As you can see from the photo below, my van is a Renault Trafic. Like I said, the Opel/Vauxhall Vivaro and the Nissan Primastar are essentially the same van, so apart from the sticker, once you've removed the engine cover that sits on the top of the engine, you should be looking at this view below, which is the airbox and the MAF sensor visible towards the back of the engine bay.
How Does the MAF Sensor Get So Dirty?
The MAF sensor is in the flow of the intake air. It is situated behind the air filter, which will clean the air to some degree, but there are still many thousands of litres of air that flows past this sensor. Over time, it will get dirty. A clean MAF sensor is vital for correct and efficient engine performance.
Above is a closer view of the MAF sensor. The design of the engines on these vans changes slightly over the years as there are several engines including the 1.9 dci, the 2.0 dci and the 2.5 dci.
On all of these, the MAF sensor is in line with the pipe that feeds the air into the engine (it has to be as it is measuring the air going in after all!), so it isn't too tough to find. The photo above depicts a 1.9 dci engine; you can see the MAF sensor just above the airbox.
To access the sensor, the first thing to do is to unplug the connector.
Remove the connector first
Pop this jubilee clip off
Pull off this pipe
After you've removed the pipe, remove both airbox bolts. There's one on the right and one on the left; I've taken a photo of the one on the right. I couldn't easily get the camera to the one on the left as it's a bit obscured, but it's not tough to find.
After you've undone both bolts, a bit of jiggling will see the airbox come out completely.
This is one of the airbox bolts
This is the MAF sensor, still screwed to the airbox
The MAF sensor unscrews from the airbox with a torx bit (T30). There are only two screws holding it in, which you can see in the photo below.
If you're going to have a go at cleaning the wires inside, remove the MAF from the airbox, then just spray them with electrical contact cleaner and just make sure you don't touch them as they're delicate. If you're just replacing the unit, then undo the two screws, attach the new MAF to the airbox and refit.
The inside of the MAF sensor
Use this instead of carb cleaner on the MAF as it doesnt leave a residue.
Well, I hope this article helped. If the MAF was the problem, then once you've plugged the new cleaned MAF sensor in, you'll be able to feel the difference straightaway.
Make sure that when you spray the MAF sensor that you use electrical contact cleaner, not carb cleaner or WD40. Contact cleaner, which can be labelled as such, or cans that are labelled up as MAF sensor cleaner (basically the same thing) doesn't leave any residue.
There are other things that can go wrong with these vans that can affect the running, but as the MAF is a pretty easy fix that often solves a lot of problems, it's a good starting point.
I have also written another article on cleaning or blanking off your exhaust gas recirculation valve (EGR valve). That is another common cause of rough running so can be beneficial if you're having problems, or if you want to prevent them. If you scroll down, then you should find the link to that article below.
Good luck working on your van and if you have any comments, please leave them below.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.