The P0786 code indicates that the transmission control module detected a problem with the range or performance of the shift timing solenoid.
The solenoid that controls shift timing can wear out or become defective, causing the transmission to miss commanded shift points.
Corroded, damaged, or loose electrical connections to the solenoid can interrupt the signal the TCM receives.
Insufficient fluid pressure or dirty fluid can affect solenoid operation and timing, leading to performance faults.
A malfunctioning TCM can misinterpret solenoid signals, but this is less common than mechanical or wiring faults.
Worn valve body or clogged passages can affect solenoid response, though this is rarer and usually accompanied by other codes.
No. The PCM is rarely the cause; the issue is usually a faulty shift timing solenoid, wiring problem, or fluid condition.
Yes. Low fluid pressure or contaminated fluid can prevent the solenoid from operating correctly, triggering the code.
If the fault was intermittent, the code may clear after a few drive cycles, but it often returns if the underlying issue persists.
It is not an immediate safety hazard, but ignoring it can lead to reduced fuel efficiency, harsh shifts, or eventual transmission damage.