Code 48 & 62

[ChevyTD]

Hi !
My truck just throwing a IAT sensor circuit high and a turbo boost sensor circuit low. Anybody have any ideas of what i should do to fix it. Do i have to replace both of the sensor on top of the intake. isn't it?. All input would be appreciate

 

[Turbine Doc]

Well they aren't related in mechanical fail mode you get high IAT with high boost, not low boost, so 1st off I suspect a electrical fault, 2 sensors in same monitoring area (boost parameters) gnds, have a look through the gnd thread in the technical reference area.

What actual boost levels are your gauges showing?

 

[ChevyTD]

well when I push my gas pedal 1/2 way to the floor to accelerated from stopping point (NOT wot) my boost gauge showing 10psi, AND 4, 5PSI CRUISE at 55mph. And it only throwing a code after about 30 min or 30, 40 miles of driving. So do you think my boost is too high? should I adjust my TM down a bit? and thank you for your reply sir

 

[Turbine Doc]

Coding at 5 psi sustained operation ??? or after hitting 10?

Sir ??? dang making me feel old , Tim or TD works

10 psi should not code, but possibly the MAP sensor is on it's way out high, you have access to a scan tool to know what the PCM is seeing for boost & IAT ?

 

[ak diesel driver]

sounds high should be about 12-14 at wot and 2-4 at cruise

 

[ChevyTD]

Yes It is coding at 5 psi sustained operation

 

[ChevyTD]

oh and no i dont have a access to a scan tool, I get my code by connecting the A and B terminal at the OBDI port. Let me trying to adjust my TM down and will get back with the result. Thank for all the help guy

 

[Turbine Doc]

5 psi should not code you nor should 10 psi generally, my suspicion now is bad MAP sensor, since you don't have a scan tool handy do you have another "6.5 guy" nearby you could swap MAP sensors with ? and see if your boost codes xfer to their vehicle or yours clears with install of theirs ?,,possibly you have a understanding part guy that realizes a MAP sensor isn't a "electronic part" that can be "harmed" and will take it back if you try one and it doesn't correct your problem. You can dial back the TM a little, or maybe just can you drive so that you don't exceed 8 psi and see if that makes a difference.

DTC 62 is triggered on low boost = when output of MAP sensor is <.8VDC

 

[ChevyTD]

I think i found the problem, and here is what i think it cause the code to pop up because of the loose connection.Cross finger

 

[Turbine Doc]

Yup that is MAP sensor looks like the harness plug is bad as well, Packard connector I could not find the p/n I'll look tomorrow to see if I can pull the p/n off of mine