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P0402 Mercury Code - Exhaust Gas Recirculation Flow Excessive Detected

- Code Popularity: 22,248 Views
- Repair Importance Level: 2/3
- Repair Difficulty Level: 2/3
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What are the Possible Causes of the DTC P0402 Mercury?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • EGR volume control valve stuck open
  • Faulty EGR volume control valve
  • EGR solenoid valve harness is open or shorted
  • EGR solenoid valve circuit poor electrical connection
  • Faulty EGR temperature sensor and circuit
⚠ Does your Mercury have Safety Recalls? → Check here

How to Fix the DTC P0402 Mercury?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

There is a factory service bulletin for the following Mercury models:

2000-2002 Mercury Sable
2001-2002 Mercury Cougar
2001-2002 Mercury Grand Marquis
2002-2003 Mercury Mountaineer
Mercury Factory Service Bulletin OBDII Code P0402 Code

Search for P0402 Mercury Questions and Answers: Search here →

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0402 Mercury code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

When is the Code Detected?

High Exhaust Gas Recirculation (EGR) flow control is detected

What are Code Possible Symptoms?

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

Code P0402 Mercury Description

Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Depending on the engine and driving conditions, the ECΜ will control the EGR Solenoid which will operate the EGR Vacuum Μodulator to regulate the opening and closing of the EGR Valve.
The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECΜ. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECΜ does not issue the pulse signal. Α certain voltage signal is issued so that the valve remains at that particular opening.
OBDII Code P0402 Mercury - Exhaust Gas Recirculation Flow Excessive Detected - AutoCodes.com
P0402 Mercury Code - Exhaust Gas Recirculation Flow Excessive Detected

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Code P0402 Mercury comments

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