Fault codeP0700

MODERATE

Transmission Control System Malfunction

What this code means

Transmission Control System Malfunction.

P0700 is a generic code: it means the same thing on every make. P0700 belongs to family P07xx — Transmission. Its page explains how to read a code and groups all its codes by part.

Gearbox control system

These codes mean the gearbox control unit has recorded a fault and asked the engine control unit to light the warning. They do not say which: the precise code is stored in the gearbox unit.

Symptoms

This code does not describe a fault: it says the transmission control unit has recorded one and is asking the engine unit to light the warning. The symptoms depend on the real fault: harsh or delayed gear changes, gearbox locked in one gear (limp mode), jerking, or just the light.

Common causes

Any internal automatic transmission fault: solenoids, speed sensors, oil pressure
Transmission fluid too low or degraded
Damaged transmission unit loom or connector
Communication fault on the network between control units
The transmission control unit itself, less often

How to diagnose it

The real diagnosis is done by interrogating the transmission unit, which holds the detailed codes — P07xx to P09xx, or manufacturer codes. A generic tool often only sees this P0700: ask a workshop for the specific read if nothing else shows.

Meanwhile check the level and appearance of the transmission fluid: brown and burnt, it explains a lot. And look for a network code alongside: it reverses the order of priorities.

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 →

Repair cost

Automatic transmission fluid change: €150 to €400. Solenoid: €100 to €400 fitted. Transmission repair or exchange: €1,500 to €4,000 and up. Do nothing before reading the transmission's own codes.

How to read this code

PPowertrain
0standardised code
7Transmission
00P0700