Pictures of Big Shots

Exhaust Gas Pressure Sensor on ISX 2006

One of the very many ways ISX motors can start running less-then-perfect is when this sensor start malfunctioning. I experienced it myself and it was quite interesting… It started with lower max turbo boost at hard pulls (26-28 PSI instead of 31-33 PSI) but it wasn’t steady, coming and going plus engine seemed to be still able to build power but it would take longer and thus took me to downshift early and more often. When I connected INSITE first thing I saw was turbo not closing like it used to, it was “working” up and down but seemed to be more likely to stay wide open in the “20’s”. Such difference in operation is hard to see immediately because that’s exactly the nature of the beast – ISX is constantly adapting turbo, EGR and fuel to whatever it wants to be. Then I figured why my jake brake is weaker – turbocharger would go only to about “55” position instead of “70” (which is turbo’s closed position with biggest restriction on the exhaust). This is sure way to confirm turbo actuation problem – when it is not closing completely during hard jake-brake operation. Started looking at the rest of the readings and… Exhaust Gas Pressure was jumping out of range and back – which was giving ECM bad idea about exhaust temperatures being to high and… apparently this was the engine computer answer to this situation… to keep turbo more “open” to help evacuate hot fumes? I guess thats is something many people describing as a “derating”.

Sensor happened to be cracked and getting water in it, replacement is simple. Looking into its pipe is also important diagnosing procedure as you want to see how heavily sooted it is inside (and clean it then). Contrary to common belief properly working ISX does not built the soot all that much…

Exhaust Gas Pressure Sensor on 2006 Cummins ISX



4 Responses


    February 13, 2013 at 7:08 pm

    • Polska Jazda

      Damn, that makes me proud that I wrote it!

      February 14, 2013 at 7:43 am

  2. Tony

    what range should this sensor be reading?
    just got my truck so i’m new to all this, when i plugged into insite i’m getting a 28-30 reading with just key on, seemed high to me. when the egr presure sensor was at 0.1. so i bought new sensor and was gonna clean the piping an replace it then i came across your write up. so i’m wondering if thats normal?

    April 12, 2014 at 5:43 pm

  3. Lee

    Where is the exhaust gas temperature sensor

    June 16, 2016 at 1:24 pm

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