2017 MG ZS: P0720 Output Speed Sensor Fault – OEM Repair Guide

The P0720 fault code on a 2017 MG ZS indicates a problem with the transmission output speed sensor circuit. This sensor monitors the rotational speed of the transmission output shaft and provides important data to the transmission and engine management systems. When the sensor signal is missing or inaccurate, the vehicle may experience shifting issues and transmission performance problems.

Symptoms

  • Check Engine Light illuminated
  • Transmission warning light displayed
  • Harsh or delayed gear changes
  • Transmission enters limp mode
  • Speedometer operating incorrectly
  • Reduced vehicle performance
  • Erratic transmission behaviour
  • P0720 fault code stored in the ECU or TCM

Possible Causes

A P0720 Output Speed Sensor Fault can be caused by a failed output speed sensor, damaged wiring, poor electrical connections, connector corrosion, or faults within the transmission wiring harness. Low system voltage, water intrusion, damaged sensor tone rings, and communication issues between the TCM and other control modules can also contribute to this fault. In some cases, an internal TCM issue may interfere with sensor signal processing.

Diagnosis

Diagnosis typically starts by confirming the P0720 fault code using a scan tool and reviewing any related transmission or communication fault codes. The output speed sensor, wiring harness, and connectors should be inspected for physical damage, corrosion, contamination, or loose connections.

Technicians will commonly test power supply, ground circuits, wiring continuity, and sensor operation. Live data analysis can help determine whether the output speed signal matches actual vehicle operating conditions. The OEM repair manual is particularly valuable because it provides wiring diagrams, connector pinouts, sensor specifications, component locations, and manufacturer-approved troubleshooting procedures.

Recommended Resources

OEM Service and Repair Manual

The OEM Service and Repair Manual is the most reliable resource for diagnosing and repairing this fault. It typically includes:

  • Step-by-step diagnostic procedures
  • Wiring diagrams
  • Connector pinouts
  • Component locations
  • OEM troubleshooting workflows
  • Repair specifications and testing procedures

To order the correct OEM Service and Repair Manual for your 2017 MG ZS, submit your request using the form below and our team will provide the ordering details.