The complaint

A Mazda with the “Sky Active” FW6A-EL transmission has its Check Engine and A/T Warning lights illuminated, with the following trouble codes stored in TCM memory:

• P0842 “Oil Pressure Switch #1 (pressure switch B) Stuck On.”
• P0847 “Oil Pressure Switch #2 (pressure switch A) Stuck On.”
• P0872 “Oil Pressure Switch #3 (pressure switch A) Stuck On.”
• P0877 “Oil Pressure Switch #4 (pressure switch B) Stuck On.”
• P0780 “Gear Shifting Malfunction.”
• P1738 “Automatic Transmission Internal Malfunction.”

The cause

This is caused by contamination getting into the valve body mounted oil pressure switches, which are very susceptible to this condition. In addition, the TCM software may be overly sensitive to pressure switch code storage.

NOTE: If the vehicle in question has delayed engagements, this bulletin does not apply.

The correction

Replace oil pressure switches A and B, as seen in figure 1, and replace the transmission fluid filter. Program the A/T Control Module with the latest software updates.

Service information

• Oil pressure switch A: FZ01-21-2C0
• Oil pressure switch B: FZ01-21-2J0
• Transmission oil filter: FZ01-21-500

This bulletin applies to and for the following vehicles:

• 2012 – 2013 Mazda 3
• 2014 – 2018 Mazda 3 (Japan Built with VIN starting with JM1)
• 2014 – 2018 Mazda 3 (Mexico Built with VIN starting with 3MZ)
• 2013 – 2018 CX5
• 2014 – 2018 Mazda 6
• 2016 – 2018 CX3
• 2016 – 2018 CX9

Note: Use caution when removing Oil Pressure Switch Manifold “A” to avoid damaging the ATF temperature sensor.