P0237 - Map Sensor Fault?

[Andrew 0]

Hi All,

 

I've slowly been getting all of the problems with my 147 JTD Q2 resolved, some have cost me quite a lot of money. Hopefully this one not so much...

 

For some time now when driving in a spirited manner lets say 4000rpm ish the car goes in to safe mode and the turbo cuts out. Turn off and back on resolves it, but the engine light stays on and the code reads P0237. The garage I've been taking my car to say it happens every time at 3000milibar and I should speak with the company that provided the remap.

 

So I've contacted them, very helpful as it turns out, they tell me:

 

"0237 points to the MAP sensor being either faulty or reading out of range. What it should do is send information back to the ECU regarding the pressure change in the intake manifold when the accelerator pedal is depressed (and subsequently the pressure is created by the turbo). The ECU uses this info to prevent overboost.

 

There should be a 5v feed to the sensor, the sensor will then send a signal back to the ECU that can be measured with an oscilloscope or even a good diagnostic . The ECU then monitors the boost pressure from this to check for a voltage outside of the operational range against the predicted value it was expecting.

 

The boost pressure being delivered should match the boost pressure being demanded in the mapping, i.e. if it requests 3000mb then it will expect 3000mb, its not a case of the mapping demanding 2800Mb and getting 3000mb so it cuts out as it wouldn't demand any more if that makes sense. Other things that could possibly trigger this are a sticking waste gate which is so very common on the 1.9 8v and 16v engines."

 

I've seen this code asked about quite a lot on another forum and very little answers provided, so I though I would post it here and will look forward to reading any comments on it.

Edited February 12, 2013 by Andrew

[K9d 108]

Some weird tiny fonts going on there, so I sorted it for you.

[Andrew 0]

Cheers, I think something to do with the cut and paste! I did try to fix it.

[Bigdar 62]

Smaky should hopefully be along soon to help you

[Smaky 73]

Wat you can dois get a canof plusgas, remove the map sensor from the back of the manifold and squirt the sensor until all the gunk is cleaned out of the sensing hole, then it should read true again.

[Andrew 0]

Thanks Smaky! I've ordered a can from Amazon. I will report back, I'm sure it's going to be dirty considering the state of the EGR recently.

[Smaky 73]

You can get it from Eurocarparts or almost any motor factor and your so close to me that an outing is in order.

[Andrew 0]

I did a search for motor factors in Cheltenham, only GSF came up and their site didn't list it, so for £4 it will arrive at my door today (only 200ml though). Handy to know there is a Eurocarparts in Swindon - although the far side. I think I'm fairly close to you when I'm in work near Siddington.

 

I will get the sensor cleaned this weekend and then go from there. I do need to speak to you with regard to where I should be taking my car really.

[Smaky 73]

There's one im Gloucester too.

[K9d 108]

Is it worth me checking my MAP sensor, I still get the EML when using full throttle, it is better since I did a better repair on my turbo hose but will still come on between 3-4K RPM.

[Smaky 73]

Anything is worth a shot, especially when the check is free and easy.

[Andrew 0]

Got the can today and took the MAP sensor off..

 

 

Fairly dirty, gave it a good spray loads of blackness came out for quite some time. Will refit tomorrow.

 

(phone pics..hands were too dirty for DSLR)

Edited February 16, 2013 by Andrew

[Smaky 73]

Not the worst I've seen.

[Andrew 0]

I know what you mean.. I've seen one that looked furry it was so coated blackness. It can't hurt cleaning it though.

Edited February 17, 2013 by Andrew

[K9d 108]

Just taken mine off and given it a clean, was pretty mucky and almost closed up with crud.

 

Mine looked different to Andrew's, it didn't have the cage bit on it and the electrical connector is at 180 degrees to the bolt, not 90 like above.

 

Its a Bosch part and has the part No. 0 281 002 510.

 

Just realised Andrew's is a 147, so a 1.9 not 2.4.

 

Anyway to the result, I took it to the private test track near me and gave it a blast full throttle 4.5k RPM in 2nd, into 3rd EML light on at about 3.5K, which is about normal for a first run. On the return run same again 2nd gear full throttle, 4.5k RPM, 3rd gear 4.5K RPM (no light), 4th up to about 4K RPM still pulling well but running out of road and given my/Alfa crappy brakes decided it was time to lift off.

When I did get the EML the usual, 4th no power into 5th power returned.

The engine felt better and pulled well all the way through to 4.5k RPM, so it helped but hasn't completely cured it.

I think either a trip to your's Smaky or Swindon on March 7th so you can plug your computer in is on the cards.

 

Considering how much muck there was on the sensor, will my inlet manifold be filled with the same ?

[Smaky 73]

Andrews is also a JTDm not a JTD. Hence the different sensor.

[Andrew 0]

The cleaning helped lots, the car has more power and so far it's not gone in to safe mode. I've been steady with it but did it a good clean out heading down the golden valley bypass and was surprised with the improved acceleration. so far so good, I need a 'private test track' as well!

[Smaky 73]

That can be arranged

[Andrew 0]

I've given the car a bit more of a test now, I think the power is spot on, compared to what believe to be a mapped E46 Compact 320td Sport and they make around 180bhp+ and 290lbft ish. My Alfa has 100kg less weight compared the the BMW which was noticeable. I dare not do any further tests, can't afford to break anything.

 

Smacky..when you say that can be arranged..?

[Smaky 73]

I have access to runways!!!

[K9d 108]

Mine's still a pain in the arse, had to do a quick pull away earlier, go wheelspin pulling out of a junction got that under control went into 2nd and almost went through the windscreen when I let the clutch up but the engine gave nothing, luckily a quick shift into 3rd got me going again and I avoided a Merc in my boot.

 

Its also started producing blue smoke when I start it up.

[Smaky 73]

A merc in the boot could've been the best result for this one.

[K9d 108]

Cheers.

 

If I'm going to have an accident I want it to be someone else's fault so their insurance pays out.

 

Its so variable in its manifestation of the problem some times it will be fine and rev fine whilst giving loads of power others the EML will come on at 3K and everything in between.

 

I planned to use BP ultimate Diesel for a while but £40 gave me 200 miles instead of the 250 I get from normal stuff, now I'm doing 300 miles a week I can't afford that sort of hit. If it had been within 10% I would have bitten the bullet and stuck with it.

[Smaky 73]

I think this car needs the Smak downto make it behave itself.

[K9d 108]

My thoughts too.