Exhaust back pressure sensor and EGR delete

[WilliamAR]

I'm suspecting that my back pressure sensor is working bad as i'm getting P0046 errors but my turbo actuator moves perfectly. (3.0 CRD)

My question is: ¿Does the back pressure sensor samples at the exhaust manifold(before the elbow)?, ¿or it samples AFTER the elbow in the back?.
If it's the 2nd then blanking it will effectively disable the sensor..., i don't want to go buying an expensive sensor for something i will disable soon.


I can't find any engine manual for the OM642 detailing the fluid flows (the service manual is hardly useful)

[WilliamAR]

Well... i've found the info...

You can't plug the EGR elbow as the sensor is besides the EGR valve, downstream of the elbow.

So you need a special blanking plate that has a threaded hole so that you relocate the sensor there

[Stewatpark]

Some blanking plates for other diesels have a 7mm hole drilled in them . This reduces the EGR flow considerably but lets enough exhaust through to fool the sensor / computer .

[WilliamAR]

a small hole would interfere with the pressure reading as well depending on the EGR flow (for example, with full commanded EGR, it would cause a drop in pressure throwing the boost calculation in disarray) that's why there's no such option for the CRD

[alexbrown64]

I can't comment too much on the EGR delete.
I use KESS and a $50 tune to get the EGR and Swirl flap deletes.

I have seen a special blanking plate and a special tube that comes off one of them that you put your sensor into. Ive worked in that space behind the turbo and its a nightmare.

We had the P0046 recently and it was the actuator. The daughters actuator worked perfectly, but when it got hot, it had intermittent problems. At first it felt like a minor miss when under load.

Started getting worse and then finally the code popped up.
I can do an actuator swap now in about an hour. We are currently using a $100 Chinese G001.
When the actuator is disconnected, its a good idea to check and see if the turbo shaft is completely free and loose. On the daughters car it was just slightly sticky. I sprayed turbo cleaner in the intake several times and put the rest in her diesel as per instructions. Also sprayed lots of WD40 where the shaft goes into the turbo.
It all did the trick, as it really loosened it all up nicely after about 10 minutes of continual working the rod up and down/spraying etc..

Since doing the swap, the daughter has had no problems with her car.
Im usually plagued by her reporting codes. But this few weeks the car has been running great and "touch wood" we have finally gotten on top of them all.

Cheers,