The P1402 trouble code is a diagnostic trouble code (DTC) that indicates an issue with the Exhaust Gas Recirculation (EGR) system in vehicles. This code is typically defined as “EGR Metering Orifice Restricted” or “Exhaust Flap Control Circuit Low,” depending on the manufacturer. The EGR system plays a crucial role in reducing emissions by recirculating a portion of the exhaust gases back into the engine’s intake manifold, which helps to lower combustion temperatures and reduce nitrogen oxide emissions. When the P1402 code is triggered, it signals that there may be a restriction or malfunction within this system, leading to potential performance issues and increased emissions.
| P1402 Code Meaning | P1402 Code Common Causes |
|---|---|
| EGR Metering Orifice Restricted | Clogged or stuck EGR valve due to carbon buildup |
| Exhaust Flap Control Circuit Low | Faulty EGR temperature sensor |
| Malfunctioning EGR system | Damaged or leaking EGR vacuum lines |
| Faulty DPFE sensor | Malfunctioning EGR vacuum solenoid/modulator |
| Damaged electrical wiring/connectors | Corroded connections in the EGR system |
Symptoms of P1402 Code
When the P1402 code is present, vehicle owners may notice several symptoms that can indicate an underlying problem with the EGR system:
- Illuminated Check Engine Light: The most common symptom is the illumination of the check engine light on the dashboard.
- Rough Idle: The engine may exhibit rough idling or stalling, particularly at low speeds.
- Hesitation During Acceleration: Drivers might experience hesitation or stumbling when accelerating from a stop.
- Increased Fuel Consumption: A malfunctioning EGR system can lead to decreased fuel efficiency.
- Failed Emissions Test: Vehicles with a P1402 code are likely to fail emissions testing due to increased pollutants.
Technical Explanation of P1402 Code
The P1402 code primarily relates to issues within the EGR system, which includes components such as the EGR valve, EGR temperature sensor, and differential pressure feedback EGR (DPFE) sensor. When these components fail or become obstructed, they can disrupt the flow of exhaust gases back into the intake manifold.
How the EGR System Works
The EGR system operates by directing a portion of the exhaust gases back into the combustion chamber. This process helps lower combustion temperatures and reduces harmful emissions. The key components involved in this system include:
- EGR Valve: Controls the flow of exhaust gases into the intake manifold.
- EGR Temperature Sensor: Monitors the temperature of exhaust gases entering the intake.
- DPFE Sensor: Measures pressure differences in the exhaust system to determine if the EGR valve is functioning properly.
If any of these components malfunction or become clogged with carbon deposits, it can trigger a P1402 code.
Step-by-Step Diagnosis of P1402 Code
Diagnosing a P1402 code involves several steps to identify the root cause of the problem:
- Visual Inspection:
- Inspect all accessible components of the EGR system for visible damage, cracks, or loose connections.
- Check vacuum lines for leaks or disconnections.
- Test EGR Valve Operation:
- Use a hand vacuum pump to test the EGR valve. It should open and close smoothly without sticking.
- If it does not operate correctly, it may need cleaning or replacement.
- Check EGR Temperature Sensor:
- Use a multimeter to measure resistance across the EGR temperature sensor terminals.
- At room temperature (approximately 70°F), resistance should typically be between 2.4 kΩ and 3.2 kΩ.
- Evaluate DPFE Sensor Functionality:
- Check for proper voltage output from the DPFE sensor using a multimeter.
- With the ignition on and engine off, voltage readings should be around 4.8V to 5.2V.
- Vacuum Gauge Testing:
- Connect a vacuum gauge to check for proper vacuum signals at both the EGR valve and DPFE sensor while running the engine.
- Readings should vary with engine speed; low readings may indicate blockage or leaks.
Solution Methods for P1402 Code
Once diagnosed, several solutions can address a P1402 code:
Cleaning or Replacing Components
- Clean EGR Valve and Passages:
- Remove carbon buildup using carburetor cleaner and a wire brush.
- Ensure that all passages are clear before reassembling.
- Replace Faulty Sensors:
- If testing reveals that either the EGR temperature sensor or DPFE sensor is faulty, replace them as necessary.
Repairing Vacuum Lines
- Inspect and Replace Damaged Vacuum Lines:
- Any damaged or leaking vacuum lines should be replaced immediately to restore proper function to the EGR system.
Electrical Repairs
- Repair Corroded Wiring:
- Inspect all electrical connections for corrosion or damage and repair as needed.
Cost Estimates for Repairing P1402 Code
The cost of repairs associated with a P1402 code can vary significantly based on parts needed and labor costs:
- EGR Valve Replacement: $150 – $500
- EGR Temperature Sensor Replacement: $30 – $200
- DPFE Sensor Replacement: $30 – $150
- Labor Costs: Typically range from $75 to $150 per hour depending on location and shop rates.
Total repair costs can range from approximately $200 to $600, depending on parts and labor required.
Warnings and Recommendations
- Always consult your vehicle’s service manual for specific information related to your make and model before attempting repairs.
- If you are not comfortable performing these diagnostics or repairs yourself, it is highly recommended to seek professional assistance from an ASE-certified technician.
- Ignoring a P1402 code can lead to more severe engine problems over time, including increased emissions and potential damage to other engine components.
Closing Paragraph
The P1402 trouble code indicates an issue within your vehicle’s Exhaust Gas Recirculation system that requires prompt attention. By understanding its symptoms, causes, and repair methods outlined above, vehicle owners and DIY mechanics can effectively address this issue. Regular maintenance and timely repairs will not only keep your vehicle running smoothly but also help ensure compliance with emission standards.
Frequently Asked Questions About P1402
- What does OBD-II code P1402 mean?
The P1402 code indicates an issue with the Exhaust Gas Recirculation (EGR) system, specifically that there is a restriction in the metering orifice. - Can I drive my vehicle with a P1402 code?
While it’s possible to drive with this code, it may lead to increased emissions and reduced fuel efficiency over time. - What are common symptoms associated with a P1402 code?
Common symptoms include an illuminated check engine light, rough idle, hesitation during acceleration, increased fuel consumption, and failed emissions tests. - How is a P1402 code diagnosed?
A thorough diagnosis involves visual inspections, testing component functionality using multimeters and vacuum gauges, and checking for leaks in vacuum lines. - What tools do I need for diagnosing a P1402 code?
You will need an OBD-II scan tool for reading codes, a multimeter for electrical tests, and possibly a hand vacuum pump for testing valve operation. - How much does it cost to repair a P1402 code?
The total cost can range from $200 to $600 depending on parts needed and labor costs associated with repairs. - Can I clean my EGR valve myself?
Yes, cleaning your EGR valve is often possible if you have basic mechanical skills; however, ensure you follow safety precautions. - Does using aftermarket parts affect my vehicle’s warranty?
Using aftermarket parts can potentially affect your warranty; always check your warranty terms before making modifications.