Quick question on the IAT and MAP sensor

[Bigsaint]

The truck gave a check engine light at start up this morning. I did the ignition trick and received a code of P 0237 ' Turbocharger Boost Sensor "A" circuit low'. Would this be relegated to the MAP sensor, or could it be the IAT ? The truck runs the same as always, good boost, no egt problems and mileage is very even from tank to tank. After I obtained the codes, I unhooked the batts. for about 20 minutes then reconnected to clear the check engine light. Have used the truck the rest of the day, no more check engine, still running like a scaled cat.



I did a search and found that I need a 1 1/4 " socket for the MAP and a 13/16" socket for the IAT. What's the best way to clean the sensors ??? Brake cleaner, WD-40 or just wipe them with a soft cloth?



Any input from someone more experienced with this matter would be greatly appreciated.



I can tell you this, it's real nice to be able to see the check engine light, know how to get the trouble shoot codes and how to fix the problem, rather than being a mind numb robot that just runs to the dealer with every idiot light. All thanks to the TDR and it's members .



Scott W.

 

[Bigsaint]

I may have answered it for myself. At the end of my shift, I went out, started the truck and activated the ebrake for a warm up. I heard this loud whining coming from under the hood, sounded like high pitched air leak, only made the sound when the brake was on. I checked all turbo lines, all tight. Started checking the manifold bolts , the rearmost upper is MIA. I checked the rest that I could reach, one was finger loose. Would an exhaust leak cause the check engine light and respective code I received ? Not sure if it's related, but one more thing to correct tomorrow.



Scott W.

 

[nps]

Got the bolt retainers?

BigSaint,



There is a tsb on manifold bolt retainers. Go from bolt-bolt such that the adjacent bolt prevents backout. Dealer should have parts - all they do is press-fit over the bolt head. Instructions say to tap them on with a socket after torqueing. My 01. 5 had them installed from the factory.



No experience on the code but my guess is you wouldn't get the code from an exhaust leak. MAP would be the sensor reporting the code. Probably loose connection?



From what I gather IAT's have been reported dirty even with normally operating trucks. Seems they are either good or bad (bad in the sense they report erroneous temps) - don't know if cleaning really adds value or changes the operational behaviour. Others have found the IAT finger-tight loose, but it has a seat-seal so may not really be a boost-loss issue.

 

[Steve St.Laurent]

The exhaust bolt shouldn't cause that code. It could be one of two things Bigsaint - it could be your MAP sensor (I had a MAP sensor go bad and it gave the same code). It could also be the wiring harness on your PM3. My original harness had a poor connection where it connected to the MAP sensor and engine harness. If I moved it around (the PM harness where it plugs into the engine) it would be intermittent and would sometimes throw that code. Mark sent me a new harness (just the connector part, didn't have to fish the harness back through the firewall) and that fixed it. If you turn on the ignition but don't start the engine and then go under the hood and move that harness around you will hear a click in the injection pump if you're having the same problem I did with the harness.

 

[Bigsaint]

NPS, thanks for your reply. I kinda figured that the two were not related, many have had boost leaks, don't remember any that reported check engine lights. I replaced the bolt this morning, looks like it was leaking for awhile as there was a fair amount of soot on the firewall and carbon build up around the valve cover . I have an ATS manifild , uses allen key type bolts, so I don't think the DC kit will work for me. Guess I'll just have to be more dilligent in checking them in the future.



If anyone can tell me what's the best cleaner to use for the MAP sensor, I'd like to take it out and clean it a. s. a. p. I checked all MAP connections and they appear to be tight.



Thanks again





Scott W.

 

[Bigsaint]

Thanks Steve, I'll try that now. If it was the MAP sensor itself, wouldn't it throw the code all the time ? Or is it a sometimes type of condition ?



Okay, gave it a try, no clicks and no code. Guess that leaves the MAP sensor as the culprit. Thanks for the info on the TST harness.



Scott W.

 

[Ram4Sam]

Map sensor

Scott, I had the same thing happen a couple of weeks ago. CE light came on. This happened while on a mini vacation not too far from home. Truck ran fine and light went out after a few start and drive somewhere cycles. I got the same code as you. Dealer changed out, repair order basically says map sensor giving erratic and/or low voltage readings. Mopar part # 5017791-AA on the repair order.



Sam

 

[Steve St.Laurent]

When my MAP sensor went bad the check engine light would come on and go off intermittently. Never noticed any difference on the street but it did slow down my times at the drag strip.



-Steve

 

[Bigsaint]

Sam, thanks for the info and the part number, I'm going to pick one up tomorrow.



Steve, thanks again, pretty much what I figured. I'm going to take the old sensor out and clean it. If I get another code, I'll put in the new unit.



Scott W.

 

[KatDiesel]

Unless the 01. 5 manual is different from my 01 manual a P0237 points directly to the map sensor.



P0237 - MAP Sensor Voltage Too Low



MAP Sensor voltage input below the minimum acceptable voltage.





Make sure you clean the connection between your MAP sensor and your EZ and PM³ . If and when you change your MAP sensor just clean all connections as well.

 

[Bigsaint]

Thanks Kat, now for the $25,000. 00 question..... is WD 40 okay to use to clean the MAP sensor and the connections or should I be using something else ???



Scott W.

 

[Steve St.Laurent]

Scott, when I cleaned my MAP and IAT sensors I used electrical contact cleaner - should be safe for sensors. You can get it at any electronics supply house or Radio Shack.



-Steve

 

[Bigsaint]

Thanks Steve ! I promise, no more stupid questions (atleast for today ).



Scott W.

 

[Vaman]

BigSaint,



What was the outcome? I haven't used my PM Comp much lately because it starts surging and setting the check engine light. I've checked all the connections and was about ready to buy a MAP sensor (see other posts). Anyhow, let us know what happens.

 

[Bigsaint]

Vaman, I haven't had the time to take the MAP sensor out yet, but I will this week. I plan on cleaning it and putting it back in. I've been driving the truck, no more check engine light after I cleared the first one, if I get another code, will replace it with a new sensor (have a mechanic buddy that gets a 30% discount from DC, he's picking me up a new sensor today). I will defintely post the results.



Did your check to see which code is being thrown ? If you can get the code off the odometer, here's a link to what they are if you don't have a service manual... .



http://www.batauto.com/Pcodes.html



Scott W.

 

[Vaman]

BigSaint,



Unfortunately, that little code trick doesn't work on the early 24's. I was looking at replacing the MAP sensor just because I'm out of ideas at this point. All my connections are soldered in... Steve has me thinking about checking my harness now though. This is pretty frustrating. Again, let us know what you find.