A P0507 – Idle Speed Higher Than Expected fault on the 2017 MG ZS indicates that the Engine Control Module (ECM) has detected an engine idle speed that is consistently higher than the manufacturer’s programmed specification. The MG ZS uses an electronically controlled throttle body to regulate idle speed by adjusting airflow into the engine.

When the ECM is unable to reduce the idle speed to its target value, it stores DTC P0507 and illuminates the Check Engine Light. This condition is commonly caused by unmetered air entering the intake system, throttle body contamination, throttle actuator faults, or incorrect idle adaptation following repairs. However, the root cause may also involve sensor, wiring, or engine management issues.

Symptoms

• Check Engine Light illuminated
• Diagnostic Trouble Code (DTC) P0507 stored
• Engine idle speed higher than normal
• Idle speed fluctuates or surges
• Rough or unstable idle
• Increased fuel consumption
• Poor throttle response
• Engine speed remains elevated after releasing the accelerator
• Hard shifting on automatic transmission models
• Additional air intake or throttle control DTCs may also be present

Possible Causes

The fault may be caused by vacuum leaks in the intake system, damaged PCV hoses, intake manifold gasket leaks, carbon build-up on the electronic throttle body, sticking throttle plate, faulty electronic throttle actuator, throttle position sensor faults, intake air leaks downstream of the throttle body, damaged wiring harnesses, loose or corroded electrical connectors, incorrect throttle body relearn or idle adaptation following service, Engine Control Module (ECM) faults, or CAN Bus communication issues affecting throttle control. Extra air entering the engine without being measured is one of the most common causes of DTC P0507.

Diagnosis

Diagnosis begins by confirming DTC P0507 using a professional diagnostic scan tool and reviewing freeze-frame data to determine the operating conditions when the fault occurred. Live data should then be analysed to evaluate actual versus target idle speed, throttle position, throttle actuator command, manifold absolute pressure (MAP), fuel trim values, and engine load. Any accompanying intake air, throttle actuator, or fuel system Diagnostic Trouble Codes should be diagnosed first, as they may be responsible for the elevated idle speed.

A P0507 fault is not always caused by a faulty throttle body. Technicians typically inspect the intake system for vacuum leaks, damaged PCV hoses, intake manifold gasket leaks, and loose air intake connections before replacing any components. The electronic throttle body should be inspected for carbon deposits that may prevent the throttle plate from closing correctly, while the throttle actuator, throttle position sensor, wiring harnesses, electrical connectors, battery voltage, and ground circuits should also be tested. If the throttle body has recently been cleaned or replaced, the OEM throttle adaptation or idle relearn procedure should be completed using a compatible diagnostic scan tool.

If the intake system and throttle control components operate within specification, further diagnosis should include evaluation of the Engine Control Module, MAP sensor, EVAP purge valve operation, and CAN Bus communication network. Access to OEM wiring diagrams, connector pinouts, component locations, throttle adaptation procedures, circuit descriptions, and manufacturer diagnostic flowcharts is essential for accurate fault isolation. Following the OEM troubleshooting workflow helps identify the root cause efficiently while avoiding unnecessary replacement of the throttle body, sensors, or engine management components.

Recommended Resources

OEM Service and Repair Manual

The OEM Service and Repair Manual is the most reliable resource for diagnosing and repairing a P0507 Idle Speed Higher Than Expected fault. It typically includes:

• Diagnostic procedures specific to DTC P0507
• Electronic throttle body wiring diagrams and circuit descriptions
• Throttle actuator and throttle position sensor testing procedures
• Idle speed relearn and throttle adaptation procedures
• Vacuum leak inspection procedures
• MAP sensor diagnostic procedures
• Connector pinout information
• Component locations and removal procedures
• OEM troubleshooting workflows
• Repair specifications and electrical testing procedures

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