P0700 on a Subaru: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

You can usually drive a Subaru short-term with P0700, but stop if the transmission slips, shudders, or gets stuck in gear.

What P0700 means on a Subaru

On a Subaru, P0700 is the transmission control module telling the engine computer that a transmission fault is stored. The actual problem is saved as a separate code in the TCM that a basic OBD2 reader cannot display. On newer Subarus with the Lineartronic CVT, the code often points to the CVT control system.

Is P0700 common on Subarus?

P0700 appears on Subarus with automatic and CVT transmissions, especially Outbacks, Foresters, and Legacys. Subaru CVTs are sensitive to fluid condition, and low or old fluid can trigger TCM faults. Speed sensors and the transmission control unit are common failure points.

Commonly reported on: Outback, Forester, Legacy, Impreza.

Symptoms

Check engine light on
Transmission or CVT warning light
Slipping or shuddering under acceleration
Harsh or delayed shifts

Common causes

most common: Low or contaminated transmission or CVT fluid
common: Faulty transmission speed sensor
common: Failing shift solenoid or control unit
less common: Internal transmission wear

How to fix it

Fix	DIY?	Typical cost
Read the stored transmission code with a professional scan tool	Mechanic	$80–150
Service the transmission fluid	Yes	$100–250
Replace the faulty speed sensor	Mechanic	$150–400
Replace the control unit or rebuild the transmission	Mechanic	$800–3500