Mazda CX-5 P0841 Pressure Sensor Range issue and AT light on

Question

My 2016 CX-5 started shifting very hard from 2nd to 3rd gear and the AT warning light popped up on the dash. I pulled the code P0841 which points to the Transmission Fluid Pressure Sensor A. The car seems to go into a limp mode and won't shift into 6th gear at all.

Ashley Park · Accepted Answer

The fix was replacing the Oil Pressure Switch #1 (Part # FZ01-21-2C0) located on the valve body. I had to drop the transmission pan and the filter to access it. After replacing the $65 sensor and refilling with 5 quarts of Mazda FZ fluid, the shifting smoothed out immediately and the P0841 has stayed off for over 2,000 miles. Make sure to torque the pan bolts to 75 inch-pounds to avoid leaks.

wrenchqueen · Answer

This is almost always a failure of the oil pressure switch on the valve body rather than the fluid itself. Mazda has a technical service bulletin regarding these switches; you can actually test the resistance of the switch terminals to see if they are sticking open.

garagegrease · Answer

You should perform a fluid drain and fill. Even if the fluid looks good on the dipstick, fine metallic debris can clog the small screens inside the solenoid body, which leads to the P0841 performance code.

Sarah Thompson · Answer

Before replacing parts, check the wiring harness connector at the transmission. These SkyActiv units can sometimes get corrosion in the pins if the splash shield is missing or damaged, causing erratic voltage readings for the pressure sensors.

Mazda CX-5 P0841 Pressure Sensor Range issue and AT light on

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