P0746

Symptoms

• Check engine light
• delayed shifts (vehicle holds the current gear before the next engages)
• harsh or abrupt shifts with a clunk
• transmission slip - engine revs rise without matching vehicle speed
• especially under acceleration
• torque converter clutch not engaging/disengaging
• shifting ability limited or disabled (limp mode).

Probable causes

• 1) Faulty pressure control solenoid A (coil shorted or weakened by overheating, moisture intrusion, or age-related winding degradation). 2) Wiring/connector faults: corroded connectors
• broken pins
• blown fuse
• or intermittent voltage drops keeping the valve de-energized (stuck-off condition). 3) Low
• burnt or contaminated transmission fluid - cited by sources as one of the most common and cheapest-to-fix causes. 4) Hydraulic blockage: clogged valve/passages or debris raising the pressure needed to open the solenoid. 5) TCM fault or TCM communication problem (less common).

Diagnostic steps

1. Connect a scan tool, confirm P0746 and companion codes, and read the pressure control solenoid A duty cycle and voltage in live data - a duty cycle that never varies with shift demand (constant 0%) indicates a stuck-off condition.
2. Check transmission fluid level and condition; replace low/burnt/contaminated fluid (and filter per service info) before further diagnosis.
3. Verify the dedicated fuse, then measure voltage at the solenoid connector with the engine running: 12 V present with no duty cycle points to a TCM/control fault; no voltage points to wiring or fuse issues.
4. Inspect connectors and harness between TCM and transmission for corrosion, broken pins and chafing; repair as needed.
5. Test the solenoid itself per the service manual (electrical and, where specified, hydraulic/mechanical operation); replace if out of spec or mechanically stuck.
6. If solenoid, wiring and fluid are all good, evaluate valve body/hydraulic circuit for blockage and finally the TCM.