1-2 Shift Solenoid Valve

WARNING: This page is about a different car, the 2002 GMC Yukon XL, 2002 GMC Sierra, 2002 Chevrolet Suburban, and 2002 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The 1-2 shift solenoid valve is a normally open exhaust valve that is attached to the valve body. The PCM controls the solenoid by grounding the solenoid through an internal quad driver. The 1-2 shift solenoid valve is on in 1st and 4th gear. When commanded on, the 1-2 shift solenoid valve redirects fluid to act on the 1-2 shift valve. See SHIFT SOLENOID VALVE STATE & GEAR RATIO table.

There are 2 PCM related DTCs associated with the 1-2 shift solenoid valve: P0751 and P0753.

The PCM monitors the 1-2 shift solenoid circuit for an open or short to ground condition. If the PCM detects an open or short to ground condition, then DTC P0753 sets. If the PCM detects an incorrect gear ratio, then DTC P0751 sets. When DTC P0753 or P0751 sets, the PCM commands maximum line pressure, freezes shift adapts from being updated, and inhibits 3-2 downshifts.