P0723

What it means

P0723 is the generic code for an intermittent fault in the output shaft speed sensor circuit. The transmission or powertrain control unit saw the output shaft speed signal drop out, glitch or behave erratically while the car was moving, when it expected a steady signal that matched vehicle speed and the other speed inputs. Because the fault comes and goes, the symptoms may not always be present.

Symptoms

• Speedometer or speed reading jumping, dropping to zero or working intermittently
• Harsh, delayed or erratic gear changes
• Transmission stuck in one gear or in limp mode
• Gear shifts at the wrong road speed or the car won't shift up
• Torque converter lock-up not engaging, with higher fuel use
• Warning light on, possibly with a gearbox warning message

Possible causes

• Damaged, chafed or corroded wiring to the output shaft speed sensorlikely
• Loose, contaminated or corroded sensor connector or terminalslikely
• Failing output shaft speed sensor giving a dropping or noisy signallikely
• Metallic debris on the sensor tip or a damaged or dirty reluctor or tone ringpossible
• Transmission fluid leak or contamination affecting the sensor or connectorpossible
• Electrical interference or poor earth or power supply to the control unitrare
• Fault inside the transmission control unitrare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including road speed and gear at the time of the fault
2. Check for related codes such as other speed sensor, ABS or wheel speed faults, and for any manufacturer software updates or bulletins for the model
3. Inspect the sensor wiring and connector for chafing, heat damage, corrosion, fluid ingress and a secure fit
4. Wiggle test the harness and connector with live data showing output shaft speed and compare it with vehicle speed on a road test
5. Check the transmission fluid level and condition, and look for leaks around the sensor
6. Remove the sensor if accessible and inspect the tip for metal debris, damage or wear, and check the reluctor ring where it can be seen
7. Test sensor resistance or signal output and the supply and earth against the manufacturer's specification for that model
8. Check control unit power and earth connections before suspecting the control unit

How to fix

• Repair or replace the damaged wiring section, using proper soldered or crimped and sealed repairs
• Clean, secure or replace the connector and terminals
• Replace the output shaft speed sensor, and renew its seal or O-ring
• Clean debris from the sensor and repair or replace a damaged reluctor ring, which may involve transmission work depending on the model
• Correct fluid level or leaks and replace contaminated fluid as the manufacturer specifies
• Repair or replace the control unit, or update its software, only after the wiring and sensor are proven good and a known fault is confirmed

Can I keep driving?

Nearby codes

• P0722GenericOutput Shaft Speed Sensor Circuit No Signal
• P0724GenericBrake Switch B Circuit High