P0787
Shift Timing Solenoid A Low
Transmission / shift control
Generic OBD-II
Medium
What it means
P0787 means the transmission control module detected a low-voltage or short-to-ground condition in the shift timing solenoid "A" circuit. That solenoid helps control shift timing and feel, so a fault can cause poor, delayed, or slipping shifts, and the transmission may enter limp mode to protect itself.
Medium
Can I keep driving? Usually drivable but shifting may be poor or slipping and the transmission can enter limp mode — fine to reach a shop, don't delay the repair.
Common symptoms
What you'll notice
- Poor, delayed, or slipping gear changes
- Difficulty shifting or holding a gear
- Limp mode (stuck in one gear)
- Check-engine light on
Common causes
Most likely first
- Short to ground or low voltage in the shift timing solenoid A circuitLikely
- Failed shift timing solenoid ACommon
- Damaged wiring or a corroded connector at the solenoidCommon
- Low or dirty transmission fluidLess often
- Failed transmission control module (TCM)Less often
How to diagnose & fix
Work through it in order
- Scan for codes and read freeze-frame data to confirm the fault.
- Inspect the solenoid wiring and connector for a short to ground, chafing, or corrosion.
- Measure the solenoid's resistance and compare to specification.
- Check transmission fluid level and condition — service if low or dirty.
- If the circuit and solenoid are good, suspect the valve body or TCM. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0787?+
You can usually drive it to a shop, but poor shifting or limp mode means you should keep trips short until it's repaired.
Can I just clear P0787?+
It will clear, but the 'low' circuit fault returns quickly unless the short, connector, or solenoid problem is fixed.
Related codes
Often seen with P0787
Read & clear P0787 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX