Shift Malfunction (A, B, or C)
Transmission is having issues with shifting.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
Your car's transmission is not shifting gears properly. This could mean it's stuck in one gear or having trouble moving between gears.
What the computer is actually seeing
The transmission control module (TCM) monitors the shifting action. When it detects a shift that doesn't happen within a set time frame (e.g., more than 300 ms for a shift), it sets the P0780 code.
What a healthy reading looks like
TCM expects a shift occurs within 300 ms after the command is sent. If it takes longer, the P0780 code triggers.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check transmission fluid level. Should be within manufacturer specs. Low fluid often causes shifting issues. Top off if necessary, then test drive.
- 2Inspect wiring and connectors to the transmission control module (TCM) for damage or corrosion. Repair as needed and retest.
- 3Check the shift solenoid operation. Use a multimeter to check resistance against manufacturer specifications (usually around 20-40 ohms). Replace if faulty.
- 4If the above checks out, inspect the valve body for sticking or failure to shift. Possible overhaul may be required.
- 5Use a scan tool to clear the code, take the vehicle for a test drive and check if the code returns.
Common causes
- Low transmission fluid level
- Faulty shift solenoid
- Transmission valve body issues
- Worn transmission components
- Electrical connection problems with TCM
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Can I drive with this code active?
It's not recommended. The vehicle may not shift properly, leading to poor performance and potential damage.
Will this code come back after clearing?
If the underlying issue isn't fixed, the code will likely return.
Why does this code pair with P0700?
P0700 is a generic transmission fault code, indicating there's a problem in the transmission system, while P0780 specifies the shifting malfunction.
Working a real vehicle right now?
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