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I have a 2010 mack truck with a mp7 in it and i keep getting the 128 105 code for the intake temp sensor. Ive changed the sensor and the harness and swapped out the ecu for a known good one and the code still is there. It also surges at an idle. it also has an intermittent code .for number 6 injector mechanical system not responding. This is a big problem as the intake code derates the engine. Thanks for any help

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If under warranty send it to the dealer, otherwise throw parts at it. Extended warranties dont sound so bad after all (with these new engines). There are no troubleshooting books on the 07 emission MP engines and newer. The only troubleshooting guides are in the VCADS/PTT software that u can buy from a Mack dealer and put in your laptop. Sadly, with the MP engines, we dont even try to "fix over the phone" as it would take hours to explain and then without all the special tools and breakout boxes your wasting your time. With the older engines we could scan and fax pages out of the manual to the customer and help him that way but with the new stuff its impossible. By the way whats the FMI of the code and does the engine have SCR/ DEF injection on it?

Ill have to look the code up again this afternoon when the truck gets back in but if i remember right it is 128 105 5 I have the vcads/ptt software on my laptop. And have the code book and did what the code book says to do to troubelshoot the problem. Replace the sensor the harness and swapped in another known good ecm. Im thinking it is not electrical but not sure where to look. Yeah im not big on being a parts changer id rather find the problem and fix it right ive already put alot of money into this problem with the harness and sensor. Thanks

If the FMI is 5, it's an low voltage/open circuit . Make sure you have the correct sensor as the boost pressure sensor on the 07-09 DPF only engines are different that the ones on the 2010+ DPF/SCR engines. On the older MP engines the sensor is boost pressure only on the newer SCR engines its boost pressure and temp sensor all in one. They look exactly the same and will plug up but will derate and make codes appear.

It is 2 not 5 my bad. I ordered the sensor from the Mack dealer and with the vin. The part number for the sensor they sent us is 0281002743 Does that look right? The code is makeing the derate engine and the driver is crying a river over it. I called the Mack dealer that we deal with and talked to someone is service who was supose to look up something about after you replace the sensor the truck has to meet some kind of drive conduction or the code wont go away. Not sure about that as he never called me back> Go figure

If it is an MRU with an MP7, there are 2 sensors on the intake manifold, they both look exactly the same, the one towards the rear and mounted directly on the intake manifold is the boost temp sensor and thats the active code your getting. The part# is 20524936. The one mounted towards the front or on the intake maifold piping is the boost air pressure sensor. Same sensor part# is the same.

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The one you want to replace is the one that is mounted directly on the intake manifold. But to be 100% sure of the part # of the sensor, I need to know the exact model of the truck , CXU, CHU, GU, MRU or LEU. But If yor truck dosent have SCR/ Diesel exhaust fulid injection, the part # of the sensor you need should be #20524936.

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i would unplug the sensor and see if the FMI changes from 2 ( data erratic)to 5 ( open circuit). If the FMI stays the same its the harness or connector ( my guess) . If the FMI changes to 5 then plug the sensor back up and clear all codes, with the key on/engine off does the code come on? Does the code come on after first starting up or do you have to drive it under a load to get the code to become active?

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