Trans output speed sensor fault.
P0720 — also written PO72O, P 0720, 0720 — is the OBD-II code for output speed sensor. Same code, same fix: this page covers every spelling of it.
This code means the gearbox 'brain' has lost its eyes; it doesn't know how fast the wheels are turning, so it goes into a panic-stricken limp mode. Usually bits the older Nissan CVTs and Ford automatics hard.
P0720 is a transmission fault code, typically costing £150–£600 to put right in a UK garage.
What P0720 actually feels like to drive
- The speedo needle is dancing up and down or just dies completely while driving.
- Gearbox feels 'clunky' and refuses to shift out of second or third gear (Limp Mode).
- Car 'kangaroos' or jerks violently when you're coming to a stop at a roundabout.
- Engine light is on, and the 'Sport' or 'Winter' mode lights are flashing on the dash.
- The car feels like it’s lost half its power because the ECU doesn't know how fast you're going.
What causes P0720?
- Sensor failure
- Wiring
UK vehicles that throw P0720 most often
- Ford Focus 2.0 TDCi (PowerShift) 2011-2015
- Nissan Qashqai 1.6 dCi (CVT) 2013-2018
- Vauxhall Astra J 1.6 CDTi (6T45 Auto) 2014-2018
- Volkswagen Golf Mk6 2.0 TDI (DSG) 2008-2013
- Mazda 3 2.0 SkyActiv (FW6A-EL) 2013-2017
- Renault Megane 1.5 dCi (EDC) 2012-2016
How P0720 is fixed
- Sensor replacement
The P0720 misdiagnosis that wastes money
I lose track of how many times I see folks chuck a brand-new speed sensor at these gearboxes only for the fault to stick around. More often than not on the Ford PowerShift or the VW DSG units, it isn’t the sensor that’s failed—it’s the internal connector or a corroded earth wire near the battery tray. I’ve seen lads spend £150 on a sensor and three hours of labour just to find out a £2 bit of wiring was green and crusty. It’s a classic case of 'parts cannon' syndrome instead of actually checking the continuity with a multimeter first.
What a UK garage should charge for P0720
A diagnostic scan will set you back £50 to £80 depending on the kit they use. A genuine Bosch or Denso sensor is usually £60 to £120. Labour is the kicker; on some cars, it’s a 30-minute job, but on others, we have to drop the subframe or open the gearbox side-casing, pushing it to £300+. At a main dealer, expect to pay £150 an hour + VAT, whereas I’d usually get you out the door for around £250 total if it’s just a standard external sensor swap.
P0720 repair cost in the UK
Most P0720 repairs land between £150–£600 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0720
Before you let a garage swap the sensor, ask them: "Have you checked the live data for the input and output speeds while driving?" If the output speed is flicking to zero while you're moving, it’s likely the sensor or wiring. If it’s steady but wrong, it could be a mechanical slip inside the box. Also, tell them to check the 'big round plug' on the gearbox for corrosion—spray it with some electrical contact cleaner first. It costs pennies and saves you a £500 bill. If they just want to swap the box, get a second opinion from a specialist.
Can you drive with P0720?
Drivable.
Urgency: medium.