P059D

What it means

P059D is a generic code meaning the control unit has seen a voltage that is too low on the position sensor circuit for active grille air shutter A. The shutters open and close to manage airflow through the radiator and condenser, and the module monitors their position through a feedback signal. A signal below the expected range, typically from a short to earth, an open circuit or a failed sensor, sets the code.

Symptoms

• Engine warning light on
• Active grille shutters stuck open or closed, or not moving
• Engine or coolant temperature running higher than normal at speed or in traffic
• Air conditioning performing poorly, particularly when stationary
• Slightly worse fuel economy or more wind noise at speed
• Other grille shutter or thermal management codes stored

Possible causes

• Faulty shutter actuator with built-in position sensorlikely
• Damaged wiring to the actuator, such as chafing or a short to earth on the signal wirelikely
• Corroded, loose or water-contaminated connector at the actuatorlikely
• Shutter vanes or linkage jammed or broken by debris, ice or impact damage, straining the actuatorpossible
• Open circuit or lost sensor supply or reference voltagepossible
• Fault in the controlling module or its softwarerare

How to diagnose

1. Read all stored codes and freeze frame data, then note whether other grille shutter, coolant temperature or supply voltage codes are present
2. Visually inspect the grille shutters for damage, debris, ice or obstructions, and check that the vanes move freely by hand if the design allows
3. Inspect the actuator wiring and connector for chafing, corrosion, water ingress, bent pins or poor terminal tension
4. Use a scan tool to command the shutters open and closed, and compare the commanded position with the reported position
5. Check the live position sensor voltage or percentage reading, and see whether it sits low or changes when the wiring is wiggled
6. With the connector unplugged, test the supply, earth and signal wires for continuity, short to earth and correct reference voltage, following the model wiring diagram
7. Check the battery and charging system voltage, since low supply can cause false circuit faults
8. Check for relevant technical bulletins or software updates for your model, as procedures and actuator design vary by make and engine

How to fix

• Repair or replace damaged wiring and secure it clear of sharp edges or heat
• Clean, dry and repair the connector, or replace the terminals or connector if they are corroded or damaged
• Replace the shutter actuator or shutter assembly if the sensor or motor has failed
• Free or repair jammed vanes and linkage, and replace broken parts
• Update the control unit software only if an outdated calibration is a known cause for your vehicle
• Clear the code after the repair and road test to confirm it does not return

Can I keep driving?

Nearby codes

• P059CGenericActive Grille Air Shutter A Position Sensor Circuit High
• P059EGenericActive Grille Air Shutter A Position Sensor Circuit Intermittent