Few days ago, my 04 MDX D5 start flashing, upon diagnosing with my ELM327 dongle found out to be P0873 4th clutch transmission fluid pressure switch (short or stuck OFF). This seems to be a common point of failure for MDX. Fixing it is really straight forward, just get yourself equip with the right tools and the replacement parts using the correct part number.

Picture 1 & 2 are the parts ordered, from Honda in US through Mikkyangel

First you have to take of the air intake manifold, ensure you disconnect the intake air temperature sensor, also take off the engine cover using a 11mm socket. I would advise you take out the battery to prevent frustration. Leave the Battery tray except you want to replace the 3rd clutch trans switch as well. PICTURE 3 & 4

With air manifold out, battery out and engine out, Now you have good view and access to the 4th Clutch transmission switch, in the picture below you will see a brown connector, that's the sensor. There is a 10mm bolt beside the sensor that need to be taken off as well. PICTURE 5 & 6


Next: Take off the connector and use a 22mm HOLLOW socket to loosen the sensor

Picture old and new sensor

Replace with new sensor and torque it in gently, the manual recommend 14 ft.lbs force, i don't have a torque wrench, so i just tightened it not too hard.

Put everything back in reverse order and don't forget to put in your temperature intake sensor to avoid check engine light.

Nice work man! crystal clear pics. Double thumbs up

Nice thread very detailed and clear pictures