Working on an 01 2500 that is completely STOCK!!!!!!!! Vehicle keeps throwing a p0234 overboost code. If you check the running with a snap on scanner it shows 14 psi of boost at idle in park. What gives, bad MAP sensor or what????

 

Yep, bad or dirty MAP. Try that first... it is easy and cheap.

 

Thanks Ill try that.

 

Is there something to clean on the map sensor or is it just replace it? My stock 02 is doing the same thing pulling a 10,000 LB travel trailer.
Thanks

 

Mine as well but only while pulling our TT. I just used carb cleaner, sprayed it good on both sides and then let it sit in some cleaner for about 5 minutes, not the connector end but the sensor end in the cleaner. Sprayed it out again and then blew it dry with about 15psi air pressure. It helped my mileage but I still get the 234 code when I pull our TT

I'm calling edge in the AM to see about shipping my EZ back for testing.

 

Same code here, haven't tried cleaning the Map sensor. Is it difficult to remove or get to on these trucks? Anything special to do to keep from breaking or stipping it when trying to break it loose? Will the code clear itself after cleaning/replacement or will it have to be cleared with a scanner?

 

Before you blame the MAP sensor for reading 14 psi at idle, be sure your snap on scanner is correct. The MAP sensor changed from reading Gauge Pressure to Absolute Pressure around the 2000 model year. The pressure you see at idle should be 14 psi. It is far more likely the problem is in the connector to the MAP sensor. I would try some dielectric grease on the connector and several insertions to make a better contact.

 

Nothing special, my 02 took a deep well 6pt 1 1/8" socket to remove, others say it's 1 1/4" but apparently there is a new map sensor for these trucks so socket size varies. For $80 I'd clean it before replacing it.

dielectric grease, good tip, using that tomorrow.

 

Thanks for the tips and responses - I'll give them a try and report back.
Jack

 

i say that's wrong . if you are right i should be getting propane at an idle, which i'm not... my pressure switch is set to turn the propane on at 5 to 7 psi

 

I’ll bet your propane pressure switch is set to turn on at 5 to 7 psi Gauge pressure that is 19 to 21 psi Absolute pressure. Gauge pressure + 14.7 = Absolute pressure. The Snap On scanner may have been calibrated for Gauge pressure and using the pre-2000 model year MAP sensor would read correctly. With the post-2000 model year MAP, 14.7 psi gets added to the reading causing the scanner to read high by one atmosphere. This MAP puts out a higher voltage for the same pressure. I’m sure Snap On has updated software to correct the readings back to Gauge pressure.

 

you are talking about Atmospheric pressure, which is 14.73 psi at sea level, so every engine has that much even when turned off