P0236 Code

[NUKEMAN]

Keep throwing this code and my idle is sticking at 1k about half the time. Anybody know what code this is?

 

[kblranch]

PO236 Turbocharger Boost Pressure Sensor Performance/ Rationality

 

[NUKEMAN]

Thanks. So, what does that mean?

 

[JApol]

from reading my 05 manual, I would suggest cleaning the MAP sensor and cleaning out the connector.

 

[testraub]

Check fuel filter and housing too. Check for built up crud in there. I got a bad load of fuel at some point and it ran over $8000. 00. Thank the gods for insurance. Dealer replaced MAP & FCM before finding the real problem. NOTE: LOOK IN THE FUEL FILTER HOUSING. EVEN AFTERWARDS STILL A LOT OF CRUD! Don't think just changing the filter will solve the problem!

 

[NUKEMAN]

Okay, excuse my lack of knowledge, but is the MAP sensor the same as the MAF sensor behind the air filter box? If not, where is it located? Thanks for the help.

 

[jman]

My idle sticks now and again also and has for 22K miles. I haven't had any codes. This morning it was 20 degrees and I stopped at the supply house and left it running. The idle ramped to 1000 rpm for about 10 seconds and then idled down. My cold weather high idle doesn't seem to be working right and hasn't for some time now. I'm starting to wonder if I don't have a funky sensor somewhere also.



The idle sticking is more of an annoyance than anything, so I haven't stressed about it much. But I'm watching like a hawk if I see a definite solution.

 

[JApol]

Nukeman, that is the right connection,



JMan, if the engine temps get below a certain amount the ECU will start a 1000 rpm high idle to help keep temps up.

for the adjustable high idle, turn on cruise control and hit set. If high idle is enabled in the ECM the idle will increase to 1000 rpm and will be adjustable with the accel and coast switches.

If high idle is not enabled find some one with a SMARTY and have them load in the stock software, that will enable the high idle.

 

[PBrauer]

Okay, excuse my lack of knowledge, but is the MAP sensor the same as the MAF sensor behind the air filter box? If not, where is it located? Thanks for the help.

I think your 03 is diff from my 06 but...



The sensor that is the equiv. to a MAP sensor will be in or near the intake MANIFOLD. On the 06 it's a 2-in-1 pressure/temp sensor. If you have another similar sensor near the air filter it's also a combination sensor but serves a different purpose.



They use two "gauge" pressure sensors and two temp sensors (on the 06 anyway) so the computer can determine whether or not it needs to engage the fan over the intercooler. A true MAP sensor wouldn't know temp.



I'd tend to suspect the one in the manifold (boost) but with the word "rationality" in the desc. it could be seeing an "illogical" temp diff between the two. The idle could be sticking, along with some fan clutch engagement, due to a perceived high intake air temp vs what it "expects" to see. One side stuck high or the other side stuck low... This "design" is what causes your fan to "unexpectedly" come on during mild temps at altitude, etc... or at low temps w/restricted filter for that matter.



If you go to a Cummins dealer neither is very expensive. I've replaced both of mine in the past just to get them ruled out... They are diff parts but only around $20 or so each. It's been a while, one might have been more.



For anyone thinking "I always thought that was the... . ", don't feel bad. Even vendors forget that the first one is BEFORE the turbocharger and has nothing to do with "fueling"...

 

[jman]

I understand the cold weather idle up feature, but mine sticks at times when it is 80 degrees outside. It doesn't idle up on its own at that temp, but will stick at times when I come up to a stop sign and engage the clutch.



My cold weather high idle seems a little erratic. It may ramp up to 1K rpm for 20 seconds and then idle back down and never ramp up again. This is what it did Monday and it was 20 degrees. I think it should have stayed at 1000 rpm. It did this same thing last winter. Maybe I have a temp sensor giving wrong information. I don't have any codes that I know of, so it is making this a little more difficult.



The cruise control High Idle would be great, but I don't think that is available on the 03's. It seems that was an 04 and up thing.