P0786: Shift Timing Solenoid A Range/Performance
What to do
Note whether the poor changes are worse when the car is cold, when it is hot, or both equally. Timing faults are unusually sensitive to fluid condition, so that observation is genuinely useful here.
What this code means
The shift timing solenoid is responding, but not by the amount or at the rate commanded. Shift durations measured by the module fall outside the window it expects, so changes take too long or complete too abruptly while every gear remains available.
Fluid viscosity has an unusually direct effect on this particular fault, because timing is what it governs. Fluid that is too thick when cold, too thin when overheated, or simply of the wrong specification changes fill rates measurably — which is why a timing complaint that varies strongly with temperature should send the investigation to the fluid before the solenoid.
Likely causes
Start here
- Low or degraded transmission fluid · easy
- Incorrect transmission fluid specification · moderate
- Failed shift timing solenoid · moderate
Less common
- Worn valve body · specialist
- Debris in the transmission fluid · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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- The car — make, model, year and engine. The same fault behaves differently on each.
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