P099F
Shift Solenoid H Control Circuit High
Transmission
Generic OBD-II
Medium
What it means
P099F means the transmission control module detects high voltage — typically an open or a short to power — in the shift solenoid H control circuit. Because this solenoid helps engage gears, the fault usually shows up as rough or erratic shifting and can force the transmission into limp mode until the circuit is repaired.
Medium
Can I keep driving? Short trips only — expect rough or erratic shifting and possible limp mode; repair soon to protect the transmission.
Common symptoms
What you'll notice
- Rough, harsh, or erratic gear shifting
- Transmission slipping or stuck in one gear (limp mode)
- Reduced acceleration
- Check-engine light on
Common causes
Most likely first
- Open or short to power in the shift solenoid H control circuitLikely
- Failed shift solenoid HCommon
- Damaged or corroded wiring or connector at the solenoidCommon
- Low or contaminated transmission fluidLess often
- Failed transmission control module (TCM)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check transmission fluid level and condition.
- Inspect the solenoid H connector and wiring for opens, shorts to power, or corrosion; repair as needed.
- Measure shift solenoid H resistance against spec and replace it if out of range.
- If the solenoid and wiring test good, have the TCM diagnosed. Clear the code and road-test.
FAQ
Quick answers
Is it safe to drive with P099F?+
Only briefly. Rough shifting and slipping generate heat that wears the transmission, so limit driving until repaired.
Can I just clear P099F?+
It returns until the high-voltage fault in the solenoid H circuit is fixed.
Related codes
Often seen with P099F
Read & clear P099F 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