Acura RDX (2nd Gen) Third-Gear Clutch Pressure Switch Replacement

Before disassembly, verify the pressure switch is the culprit rather than fluid or wiring. Read the transmission control system with a basic OBD-II scanner; code P0848 indicates the third-gear switch or its harness, though a dirty connector can occasionally mimic it, so cleaning the contact is a cheap first check. Because the factory parts diagram does not clearly mark which unit governs third gear, work from a photo reference. On this 6-speed automatic the switch you want is switch 'B', a green-bodied unit rated 36-42 psi, mounted on top of the transmission case behind the battery and airbox.

Loosen both battery cable clamps with a 10 mm wrench and lift the leads clear, taking the negative off first. Be aware the radio, clock and adaptive settings will lose power; the audio anti-theft lock is handled at the very end of the job.

Undo the two 10 mm nuts securing the battery hold-down frame and lift the frame away. Release the two retaining clips on the fresh-air intake scoop and ease it out; it seats tightly, so expect to work it loose with a bit of wiggling rather than a straight pull.

Slide off the insulating battery sleeve and lift the battery out of the bay. The plastic tray beneath it is not bolted down; raise it and free the wiring connector clipped underneath by squeezing the sides of the plug and flipping it loose.

Unplug the oxygen sensor connector on the intake. Slacken the intake hose clamp with a Phillips driver or 5.5 mm nut driver. Separate the small metal breather tube from the intake hose, then work the intake duct and hose out of the bay, freeing it gradually where it resists. Unclip the positive battery cable channel from the airbox by pressing its two tabs from underneath and sliding the channel toward the passenger fender.

Pry up the plastic trim strip running along the top of the driver-side fender; it is held by several push clips, and any that stay lodged in the fender should be pulled out and refitted to the trim. Open the airbox, lift out the filter element, then remove the three 10 mm bolts holding the box down. Release the clipped oxygen sensor lead and lift the airbox out, which opens up access to the top of the transmission.

With the airbox out, the pressure switch is exposed on the top of the transmission case. Match it to your reference photo to be sure you have the third-gear unit and not an adjacent switch. Depress the locking tab and disconnect its electrical connector.

Fit a 22 mm deep six-point socket squarely over the switch and back it out. Pack a shop towel around the base beforehand, as a small amount of ATF will weep from the port once the switch clears the threads, though the loss is minor. Recover the old sealing washer if it remains stuck to the case.

Fit the new switch (P/N 28600-R94-004) with a fresh sealing washer (P/N 90471-PW7-A00); never reuse the old washer. Start it by hand to avoid cross-threading, then tighten. The original poster could not confirm a torque figure and set it by feel; later contributors and the equivalent Honda service spec give 15 ft-lb, so use a torque wrench with a 3/8-inch adapter, since many 1/2-inch wrenches begin above that value. Reconnect the electrical plug once the switch is torqued.

Rebuild in reverse: airbox and its three bolts, fender trim clips, intake duct and breather tube, oxygen sensor plugs, battery tray wiring, battery, hold-down frame, air scoop, and finally the battery cables. Top off any lost ATF if needed. Clear the P0848 code with a scan tool. When the radio requests a security code, hold its power button for roughly ten seconds to dismiss the prompt; RDX radios from 2013 onward require no code. Finish with a test drive to confirm the harsh shift is gone.