Powertrain, generic · Transmission

P0720 Output Shaft Speed Sensor Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

The output shaft speed sensor (Hall or inductive) reports the speed of the transmission output; it gives the gear ratio together with input speed and on many vehicles also the road speed for speedometer and cruise control. P0720 is the general circuit code. Ford also uses it for 'no signal': while engine and turbine speed show the vehicle moving, the sensor reports under 100–200 rpm for 5–30 s; ZF's 6HP26 in Ford vehicles flags an open or short after 0.6 s. Subaru-based systems (Saab 9-2X) flag an impossible 255 km/h or 0 km/h while driving and light the MIL after two trips, substituting the other sensor. GM does not use P0720 but P0722. Speedometer and cruise control may fail, often with a vehicle speed code as well.

Likely causes

Speed sensor faulty (Hall IC or coil open or shorted)
Connector or harness corroded, chafed or loose pins (with internal sensors also the pass-through connector)
Metal debris on the sensor magnet or damaged reluctor wheel
Transmission module or its sensor supply faulty

Symptoms

  • Speedometer drops out or jumps
  • Warning lamp, limp mode or fixed gear
  • Harsh shifts, cruise control not working

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–450
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

What to check first

  1. Inspect sensor and wiring
  2. Check signal on a scan tool

Parts involved

output speed sensorsensor wiringtransmission control module

Related codes

P0721P0722P0723P0715P0500P0502

References: newtonnet.co.uk, fordservicecontent.com, saabwisonline.com, techtips.ie.