Help/advice needed. P0236 error code

[Neil_Bulbeck]

Hi. Sorry if this has been covered before or in the wrong topic. I can’t seam to find anything regarding my issue.

So the last couple of weeks ago my EML light came on. I lost all boost from my turbo and was in limp mode. The code that came up on a snap on and my own OBD2 reader was P0236. Turbocharger/supercharger boost sensor A circuit range/ performance.

I’ve put a fuel additive in the tank. Archoil d max turbo cleaner to be exact. With no real effect as such. (Only done 70 miles with it in.) as i understand that the turbo vanes stick. My mate pressure tested the actuator. This wasn’t holding pressure or moving freely but after a while with the pump it was. Code cleared and boost was back. Until the engine was switched off.

I now have figured out that once the van is moving, if I turn engine off and then back on as if I bump start it I have boost again.

I was going to replace the map sensor and or the pressure control boost sensor but wanted to get people’s views or opinions first.

I checked a few pipes today but couldn’t see and splits etc. Cleaned the map sensor or what I think is the map. But it’s still the same.

I hope someone can shed some light.

Thanks. Neil.

[SnoWhite]

Neil it would help if you give us a bit more information or at least the engine specs of the Caddy you own.

You mentioned vanes gumming up so I am guessing a 1.9tdi PD. A while back I had the same engine in a golf 4motion estate and from around 120k miles it started occasionally going into limp mode , getting progressively more frequent to the point of making it a total liability to use. Of course I tried the cheaper solutions first - so cleaning/replacing sensors but nothing worked long term, until I bit the bullet and had a fully reconditioned (exchange) turbo fitted and problem solved - and its still going strong at 250k.

In the short term you might try moving the VNT valve movement linkage back and forward through its full range of movement. Wait until its cold as stuff by the turbo gets very hot. The linkage is located around the back of the turbo and if you are lucky you might be able to clear gunk preventing the vanes moving and get them moving freely again at least for a while. That may provide a short term solution.

I considered but eventually discounted another rather scary solution on YouTube video using oven cleaner to fill the turbo and clean the vanes from the inside. But the video gave no indication if it provided a long term fix - and that stuff is really nasty - so you would need to take great care not to get it on skin or in eyes if you decide to try that solution.

[Neil_Bulbeck]

Hi SnoWhite.

Sorry, yes it’s a 1.9tdi 105bhp with 120k. Not with the van at the moment so can’t get you the engine code. ( where are they located on that matter)?

I have played with and got the actuator at the front of turbo moving freely. Or is the VNT linkage something different? Sorry if I’m being dumb.

I’ve seen on YouTube that people have done the oven cleaner trick,but there’s something about it that really puts me off.

I’m hoping the archoil I put in will start to breakdown the carbon deposits. But don’t think it’ll be a quick fix.

I’m tempted to book it in at a local VW specialist. As they have a proper scanner and I’m completely stumped. Plus don’t want to replace parts that are perfectly fine.

[Neil_Bulbeck]

Just an update.

Turned out to be the MAP sensor. Cheap simple fix.