Fault code P1539 – a step-by-step guide to diagnosing and fixing it

Error code P1539 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system detects a fault in the throttle control or idle control system. This manufacturer-specific DTC P1539 mainly affects the electronic throttle position and can have different meanings for different vehicle brands.

What causes can this error code have?

• Defective throttle valve unit
• Dirty throttle body
• Faulty throttle position sensors
• Damaged cable connections to the throttle valve system
• Defective engine control unit
• Loose or corroded plug connections
• Vacuum leaks in the intake system
• Defective idle speed actuator
• Worn throttle valve shaft

What symptoms occur in parallel with fault code P1539?

• Idling problems: Unsteady or fluctuating idling
• Starting problems: Difficulty starting the engine, especially when cold
• Engine speed fluctuations: Uncontrolled changes in engine speed
• Reduced engine power: noticeable loss of power when accelerating
• Stalling of the engine: Engine stalls while driving or idling
• Increased fuel consumption: Significant increase in fuel consumption
• Poor throttle response: Delayed response when accelerating

How can the problem of error code P1539 be rectified?

• The repair requires a systematic diagnosis of the throttle valve control and the idle control system.
• Thoroughly clean the throttle body and remove any deposits, then carry out basic adjustment
• Replace the defective throttle valve unit completely and have it taught electronically
• Repair or replace damaged cable connections and clean plug connections
• Check throttle position sensors individually and replace if defective
• Locate and seal vacuum leaks in the intake system
• Check engine control unit for functionality and replace if necessary
• Remove idle speed actuator, clean or replace if worn