The Dieselman EGR defeat circuit

The Dieselman EGR defeat circuit

Over the last year we have had many problems with our car, and I have tried many things to fix it. I may have given the impression when writing about the P10A4 error that I jumped straight to the solution, but I actually tried a few other things first, one of which was an EGR delete. There is of course no page on how to do an EGR delete on a CRD PT Cruiser, but fortunately it has a Mercedes Benz C Class engine, for which there are lots of guides. The one I ended up using was this guide from the UK Mercedes Benz owners forums. The circuit I used was provided by Dieselman, which is attached (above) or can be picked up from the photobucket link in the forum page. The photos below show how the mod was applied to the PT Cruiser. Ideally the mod should be applied within one of the plugs for the engine management computer, however the necessary contacts are spread over two plugs, which makes this mod messy if applied at the plug end. In the end it was neater to add the mod at the solenoid/ MAF plug end, especially as these are close together and this makes it easy to remove, whilst standing on the pavement, without taking half the engine apart (which I was worried I’d have to do if it didn’t work and I ended up with a car stuck in limp mode).

Has it made a difference? I have no idea, the car was so poorly before I replaced the turbo hose that any improvement it made was rendered insignificant up by the massive improvement the replacement of the hose made. I also don’t know if it made the engine any hotter than before because after my water pump mod the engine has never, ever (except for the occasional massive glitch), gone any warmer than the mid-range.

All I can say is that the layer of crud in my intake manifold I found when I replaced the turbo hose did not look like it was good for the engine, and maybe without this mod the car would be a little more smoky.

Please note; in the following images I show the air box and ECM totally removed, this is not necessary to do this mod the way I have here, I only removed them as I was, to put it bluntly, making this up as I went along. Of course taking the air box out does make it much easier to wrap the EGR solenoid plug, to remove it (air box) take the air intake filter cover off, disconnect the air intake hose, remove the filter, then the front of the car that holds the radiator/ boot slam catch in place (see my post on the P01A4 error code) and finally pull the box up by hand. Installation is the reverse of removal.