AutoCodes - Buick - P0406 BUICK

P0406 BUICK Code - Exhaust Gas Recirculation Position Sensor Circuit High Voltage

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3
Table of contents

|P0406 BUICK code possible causes

  • Exhaust Exhaust Gas Recirculation Position Sensor
  • Exhaust Gas Recirculation Position Sensor harness is open or shorted
  • Exhaust Gas Recirculation Position Sensor circuit poor electrical connection

|How do I fix the P0406 BUICK code?

Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

|Cost of diagnosing the P0406 BUICK code

Labor: 1.0

The cost of diagnosing the P0406 BUICK code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

|What are P0406 BUICK code possible symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

|P0406 BUICK code description

The Engine Control Module (ECM) tests the Exhaust Gas Recirculation (EGR) system during deceleration. The ECM does this by momentarily commanding the EGR valve to open while monitoring the signal circuit of the manifold absolute pressure (MAP) sensor. When the EGR valve is opened, the ECM will expect to see a predetermined increase in MAP. If the expected increase in MAP is not detected, the ECM records the amount of MAP difference that was detected and adjusts a calibrated fail counter towards a calibrated fail threshold level. The number of EGR flow test counts required to exceed the fail threshold may vary according to the amount of detected EGR flow error.
The EGR valve position sensor is monitored by the ECM. The 5-volt reference circuit, the low reference circuit, and the EGR valve position signal circuit are used by the ECM to determine the EGR valve position. The ECM compares the EGR Position Sensor parameter with the desired EGR Position parameter when the valve is commanded open or closed.
The ECM controls the EGR valve with a solid state device called a driver. The driver supplies the EGR solenoid with 12 volts that is pulse width modulated (PWM) through the EGR solenoid high control circuit. A ground path is provided by the ECM through the EGR solenoid low control circuit.
When the ignition switch is turned ON, the ECM records the EGR Learned Minimum Position. The ECM compares the EGR Learned Minimum Position parameter to the EGR Position Sensor parameter.
OBDII Code P0406 Buick - Exhaust Gas Recirculation Position Sensor Circuit High Voltage -

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|P0406 BUICK code comments

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Repair Importance Level: 3
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