Fault codeP0784

MODERATE

4-5 Shift Malfunction

What this code means

4-5 Shift Malfunction.

P0784 is a generic code: it means the same thing on every make. P0784 belongs to family P07xx — Transmission. Its page explains how to read a code and groups all its codes by part.

Gear ratio and shifting

The gearbox control unit compares the speed of the input and output shafts: in each gear, the ratio between them is known. When it is not the expected one, or a shift takes too long or too little time, something is slipping inside the gearbox.

What you notice

Revs flaring without the car accelerating, harsh, slow or missing shifts, a gearbox in limp mode.

How to check it

Check the fluid level and condition first: low or burnt fluid causes many of these faults. Then the solenoid and speed sensor codes, which may explain the problem. If none is present, the clutches or bands inside the gearbox may be worn, a job for a gearbox specialist.

Watch it live in Klaro

With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:

Engine RPM
Vehicle speed

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
7Transmission
84P0784