A P0998 DTC means that the ECU has detected a low voltage signal coming from the shift solenoid F control circuit. This means the computer is not able to command the solenoid On and Off.
How Serious is the Code?
Most of the time, the transmission problems associated with a P0998 diagnostic trouble code start out very small. But then they can escalate to the point that your vehicle is almost impossible to drive.
Symptoms of a P0998 include:
- The transmission feels like it’s jerking when it changes gear
- The transmission won’t shift into gear
- The transmission fluid level is too low
- The transmission fluid and filter need to be changed
- Damaged/broken wires
- Broken/corroded connectors
- The shift solenoid has stopped working
How to Diagnose the Code?
Since the level and condition of the transmission fluid will directly affect the operation of each shift solenoid, it should be the first thing that is checked when diagnosing a P0998 OBDII trouble code. The wiring and connectors along the transmission wiring harness are also a factor. If no issues have been found up to this point, then the shift solenoid F will need to be directly tested.
What Repairs Will Fix P0998?
- Service the transmission
- Replace or repair damage wiring/connectors
- Replace shift solenoid
- P0997 – Shift Solenoid “F” Control Circuit Range/Performance
- P0999 – Shift Solenoid “F” Control Circuit High