Transmission

P0780 — Transmission Shift Malfunction

Severity: medium Drive with care, to a shop

What P0780 means

P0780 is set when the transmission control module (TCM) sees that a commanded gear change did not match the actual result, such as a late, missed or flared shift. Normally the TCM commands shift solenoids in the valve body, hydraulic pressure applies the right clutches, and speed and range sensors confirm the outcome.

Symptoms

  • Harsh or jerky shifts
  • Delayed shifts or RPM flare between gears
  • Transmission warning light or Check Engine light on
  • Stuck in one gear (limp mode)
  • Slipping under acceleration
  • Delayed engagement into Drive or Reverse

Possible causes

  1. Low or old, contaminated ATF
  2. Failed shift solenoids or valve body problem
  3. Internal mechanical wear in clutches or pump
  4. Damaged wiring or connector at the transmission
  5. Faulty transmission range (TR) sensor or speed sensors
  6. Lost adaptive values after service or fluid change
  7. TCM fault (uncommon)

How to diagnose

  1. Scan all codes and freeze frame data and note any related transmission codes
  2. Check ATF level and condition: color, smell, metal debris
  3. Inspect the transmission harness and connector for damage, fluid and corrosion
  4. Check the TR sensor and its adjustment
  5. Compare input and output speed data on a scan tool to find which gear slips
  6. Test shift solenoids and their resistance against specs
  7. Perform a line pressure test if needed
  8. Look up service bulletins and TCM software updates

Common fixes

  • Correct the fluid level or replace ATF and filter
  • Repair wiring or the connector
  • Replace faulty solenoids or sensors
  • Reset and relearn transmission adaptations
  • Repair or replace the valve body, clutches or the transmission

Questions and answers

Can I drive with a P0780 code?

Only a short distance and carefully, to a shop. If it slips or shifts violently, don't drive it, or you risk ruining the transmission.

Can low fluid cause P0780?

Yes, it is one of the most common causes. Check fluid level and condition before paying for deeper diagnosis.

Will clearing the code fix it?

Only temporarily. If a solenoid or worn parts are the cause the code will return; a relearn only helps when adaptations were off.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.