Replacing G28 Engine Speed Sensor on Common Rail (CBEA CJAA)

There have been a few threads asking about the G28 sensor on the common-rail cars but there wasn’t really any straightforward information about it. I just had to replace one on a 2010 and thought I’d share my experience.

Sensor Location

The sensor is actually bolted on to the rear main seal. The rear main seal has a tone-ring built into it and the crankshaft position sensor reads that ring.
(This also means that the rear main seal must installed properly timed, see other thread for rear main information)

Factory Method

There is a hole in the block just behind the oil filter flange where this sensor and connector are located. The factory method suggests removing the oil filter flange, including the cooler, to access the sensor.
Removing the oil filter flange requires removing most of the intake parts, including the EGR & air flap plus hard boost pipe. You also need to disconnect the turbocharger oil feed line. Plus, you’ll need to drain (or evacuate) the oil filter flange itself before removing it to limit the amount of oil that is spilled. Once you remove the flange you will still lose 1/4-1/2 gallon of oil.
This is the image of the sensor in the FSM.

Screen Shot 2017-06-01 at 11.30.21 AM

This image is NOT realistic. This is what is looks like in real life after you take off the filter flange + everything else that is in the way, which on a common-rail is a lot of stuff.


Further complicating the issue is that getting to the screw is not a straight shot, requiring a ball-head allen. The bolt is most likely going to have corrosion or debris in it, limiting the ability of the bit to get a good hold on the bolt.

Remove the Transmission Instead

After spending 4 hours getting to the sensor and trying to a bit into the bolt I was still not successful and looked for alternative options. It occurred to me that pulling the transmission would give direct access to the rear main seal and sensor.
After removing the transmission, clutch & flywheel things look like this:

IMG_2178Here you can easily get to the bolt with a 1/4 drive racket and 4mm allen bit.
Personally I’ve done enough clutch jobs that removing the transmission is not a big deal. I have hoists and stands to support the engine and easily remove the transmission. I realize not everyone has these things. However, I do not think it is realistically possible to replace the sensor via the factory method. Plus, there was enough debris on the rear main seal tone ring that I worry might cause issues in the future, removing the transmission allows me to clean that debris off.

  1. I just changed mine, did not have to remove transmission or oil filter housing from block. 2011 jetta cjaa. Oil cooler was removed, (seals were shot, so that’s good) and intercooler pipe, all done from the bottom. Used a 6″ long 4mm Bondhus ball end Allen driver. Have pics.


    1. Post pics, please. I can’t see how it is possible to get to the sensor with the oil filter flange in place.


    2. Hi Todd any pics you can send to me please? Thx…….. Im at


  2. I have just spent the afternoon trying to remove the G28 Crankshaft position sensor from 2010 VW T5 2.0 TDI CR Transporter. On this model there is easy access to the sensor plug aperture with no obstructions like oil cooler etc so it seemed worth having a go, having not attempted one before. I started with a long 4mm ball headed allen key which I engaged into the bolt head with little trouble. Unfortunately ball headed allen keys have less surface area contact with the bolt head so it just turned within the bolt head (the bolt is quite tight). My next attempt involved putting a plain long 1/4″ drive in the vice and putting a slight a slight bend in the end of it to help with the angled access, I intended to us this method just to crack the bolt loose and use the ball headed allen key to unscrew it. This worked much better and I managed to apply a decent torque to the bolt. Unfortunately the bolt head rounded out, probably because of the damage that the ball headed key did, but I have a feeling if I had tried this method first I may have been successful. I hope this experience is helpful to somebody.



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