Popped A Code

[rebel_horseman]

Popped a code at lunch. No check engine light but the Evo pulled up P0236 "turbocharger Boost Sensor Malfunction" or something. Can someone expand on this and confirm this is the right description.

Any thoughts as to the culprit and how to fix it. The truck is defueling below 2k RPMs and drives like a dog but above that it runs about normal. Thoughts?

TIA

Brian

 

[jlayne]

sounds like the map sensor on the firewall is doing something funky

or it overboosted (is that a word) that will defuel and set a CEL but that is a different code i'm pretty sure without looking at my book

 

[rebel_horseman]

That's the odd part, there was no CEL...just defueling and no low-end power. I was thinking maybe the MAP sensor too but want to get some more input.

 

[jlayne]

That's the odd part, there was no CEL...just defueling and no low-end power. I was thinking maybe the MAP sensor too but want to get some more input.

yeah thats what makes me think map sensor, i think the overboost is a different code and it WILL turn on the CEL...

did you have it tuned up with a hotter than stock program or messed with the wastegate? its almost impossible to overboost a stock or close to stock truck or if the wastegate hasn't been messed with by a boost tube or adjusting it rod.. if your wastegate is working and hasn't been modified or you didn't have a high hp. tune on the truck that would pretty much rule out the overboost

 

[rebel_horseman]

I've been running my Evolution on Level 2 (80hp) for about a week now but the turbo is stock and the wastegate is unmodified. The odd thing is, this started in traffic at low speeds. At one light the truck was running perfect adn a block later when I took off from the next light it felt like it was back on the stock setting. If I stayed in it once I got above 2k or maybe 2400 the PCM started adding fuel like normal and the truck seemed right (plenty of smoke and performance). On the interstate the truck was slow to respond...if I let off the go pedal and boost fell then it took several seconds to build up boost again which made me think maybe intercooler boots. I checked the intercooler boots to see if I slipped one and they looked fine.

 

[Mike]

Code = P0236

refer to footnote = b

Circuit index = MAP

Condition description = Turbo boost sensor A circuit performance

Probable cause = Restricted inlet/exhaust/supply hose, missing hose

*footnote = b MIL (OBDII illuminates after second consecutive fault.




Hope that helps Brian, looks like the CEL only comes on after the second time the code is set.

 

[rebel_horseman]

Thanks Mike. Anyone have a pic of the MAP or an approximate location so that I can check it out? Worse case scenario I"ll have to get a new MAP sensor. Anyone know how much those puppies cost?

 

[Mike]

On the firewall, left side of engine bay, should be a black 1/4'' hose going to it coming from down on the intake plenum or thereabouts.

 

[rebel_horseman]

Cool. Going to go check it out in a little bit if I can sneak out. Thanks for the help fellas.

 

[Mike]

Take a look, the dang hose might have fallen off?

 

[rebel_horseman]

No luck. The connections and tube are all in place and on tight. I'm gessing my MAP sensor is shot. Anyone know if I can get this at an IH parts department or do I have to go to the stealer? Alaso the part number in the Tech Articles was for a 96-98 unit. Is this the same part number for the Super Duty trucks like I have?

 

[rebel_horseman]

Piece of info.

MAP Sensor FoMoCo Part # F8UZ-9F479-BA

Local Ford parts department : $102.16 and early next week to get it in. O'Reilly Auto Parts $53.99 and it'll be here in the a.m.

 

[geonc]

Have you tried unplugging the MAP?
That will show a check eng light but will go out when re-connected.

Don't forget to get some dilectric grease

 

[rebel_horseman]

Went ahead and chaged the MAP this morning. Easy fix for the most part...worst part was getting the cotton picking plug off the sensor. Hopefully this will do the trick.

The factory MAP started working perfect after I left work yesterday so now I have a new one and a questionable backup.

'Preciate the help fellas.