W166 Air Intake Temperature Sensor Help Please ! Desperate:(

[Crosser74]

Hi All

2014 ML250 Diesel - Going on holiday Sunday (or maybe not!). Car developed a fault and a generic code reader read it as P011427 INTAKE AIR TEMPERATURE SENSOR 1 (BANK1) HAS A SPORADIC MALFUNCTION. THE SIGNAL CHANGE RATE IS ABOVE THE PERMISSABLE VALUE.

A mechanic cleared the fault and then unplugged the MAF sensor while it was running and the exact fault reappeared. I replaced the MAF sensor from main dealer @ £244 (which is a recon unit as it comes in a section of pipe - I guess they replace the sensor )

Fault is still flagging - I have tried clearing codes. It goes into limp mode and has no power and holding gears.

Hope someone can help!! TIA

 

[supernoodle]

Temperature sensors are relatively slow reacting devices and the air itself cannot change temperature rapidly. So if signal at input pin changes too quickly to be real, an implausible rate of change error will set.
It could be sensor but more likely poor electrical connections or wiring problem. To change the MAF without first checking was a bit rash.

 

[ajlsl600]

Hi All

2014 ML250 Diesel - Going on holiday Sunday (or maybe not!). Car developed a fault and a generic code reader read it as P011427 INTAKE AIR TEMPERATURE SENSOR 1 (BANK1) HAS A SPORADIC MALFUNCTION. THE SIGNAL CHANGE RATE IS ABOVE THE PERMISSABLE VALUE.

A mechanic cleared the fault and then unplugged the MAF sensor while it was running and the exact fault reappeared. I replaced the MAF sensor from main dealer @ £244 (which is a recon unit as it comes in a section of pipe - I guess they replace the sensor )

Fault is still flagging - I have tried clearing codes. It goes into limp mode and has no power and holding gears.

Hope someone can help!! TIA

Sporadic, sounds like wiring or dodgy connections, or sensor starting to breakdown. Anyway sorrio hope ur soon sorted, do advise ur solution. . My ml 250 recently turned into a brick at a most inconvenient time, as such I no longer trust it to get me where I need to be. So it's going soon. I have one trip to do to Yorkshire first and I feel I must join AA relay if I want to be sure I will get home. Twas not the idea I had in mind when I bought the brand, we live n learn. I did the same trip 4 days later in 1968 NG Tf towing m bike never missed a beat. Lesson learnt. 4 me anyway.

 

[alexanderfoti]

Intake air temp sensor is in the egr/intake pipe and not part of the maf.

With that code, I'd check the wiring first.