How Serious is the Code?
Although the transmission problems associated with a P0773 DTC might only be intermittent at the moment. They will soon get worse, effecting both the safety and drivability of your vehicle.
Symptoms
Symptoms of a P0773 include:
- Check engine light
- Limp mode
- Harsh, delayed or erratic shifts
- Slipping in-and-out of gear
- Engine stalls
- Getting stuck in gear
- Vehicle won’t move when in gear
- Reduced fuel economy
- Transmission overheats
Causes
- Low transmission fluid
- Dirty transmission fluid / filter
- Frayed wiring / damaged connectors
- Failed solenoid
- Failed transmission pump
- Pressure blockage
- Valve body issue
- TCM or ECU failure
How to Diagnose the Code?
If the transmission fluid contains any dirt, sludge or metallic debris, the solenoids may not function properly. The presence of metal shavings could also indicate internal component failure, which is why checking the ATF level and condition should be the first step in diagnosing a transmission solenoid fault code. If the fluid is dirty and pressure blockages are suspected, then a transmission flush may be performed.
If there are no obvious maintenance related issues, then the wiring and connectors should be checked for evidence of damage and/or corrosion. If everything appears fine, then the shift solenoid will need to be tested according to the manufacturer’s procedure. If no issues have been found by this point, then the problem could lie with the transmission pump, valve body, or pressure regulator.
Common Mistakes When Diagnosing
Even though most automatic transmissions operate in a similar fashion, not all the components work in the same way. Depending on the age and type of vehicle, the different types of solenoids can require different testing procedures to get accurate results.
What Repairs Will Fix P0773?
- Changing the transmission fluid and filter
- Replace faulty solenoid
- Repair or replace a faulty transmission pump
- Repair or replace defective transmission valve body
- Perform transmission flush to clean passages
- Cleaning corrosion from connectors
- Repairing or replacing wiring
- Flash or replace PCM/TCM
- Install a rebuilt or remanufactured transmission
Related Codes
P0770 – Shift Solenoid ‘E’
P0771 – Shift Solenoid ‘E’ Performance or Stuck Off
P0772 – Shift Solenoid ‘E’ Stuck On
P0774 – Shift Solenoid ‘E’ Intermittent