P0789 Code: Shift Timing Solenoid A Circuit Intermittent
🟠 Moderate severity · drivable
Drivable, but shifting may come and go unpredictably; the fault can worsen while driving.
What P0789 means
The signal from shift timing solenoid A drops in and out instead of staying steady. The transmission may shift fine sometimes and then shift harshly or stick at other times, which makes this fault tricky to reproduce and diagnose.
Symptoms
- Check engine light is on, sometimes flashing or resetting
- Shifts fine some days, harsh or delayed other times
- Transmission intermittently stuck in gear
- Slipping during acceleration
- Reduced fuel economy
Common causes
- most common: Loose or worn connector at the solenoid
- common: Damaged or chafed wiring
- common: Faulty shift timing solenoid A
- less common: Internal transmission problem
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Clean and secure the solenoid connector | Yes | $0–50 |
| Repair damaged wiring to the solenoid | Yes | $50–150 |
| Replace shift timing solenoid A | Mechanic | $150–400 |
Frequently asked questions
Can I drive with a P0789 code?
Yes, but the transmission can act up at any moment. If it starts shifting badly, pull over and get it towed rather than pushing it.
Why is P0789 called intermittent?
Because the solenoid signal cuts in and out, so the code may set and clear on its own and symptoms come and go.
How do you fix an intermittent P0789?
Start with the cheap fixes: clean the connector and check the wiring for chafing. If those are fine, the solenoid is usually the next step.
Related codes
P0785
P0785 Code: Shift Timing Solenoid A Circuit Malfunction
P0786P0786 Code: Shift Timing Solenoid A Range/Performance
P0700P0700 Code: Transmission Control System Malfunction
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.