P1402: EGR Metering Orifice Restricted

Definition

The OBD2 code P1402 indicates that the EGR (Exhaust Gas Recirculation) metering orifice is restricted, which can affect the flow of exhaust gases back into the intake manifold, potentially leading to increased emissions and engine performance issues

Common causes

Clogged EGR metering orifice
Carbon buildup in the EGR system
Faulty EGR valve
Vacuum leaks in the EGR system
Blocked EGR passages
Malfunctioning EGR pressure sensor
Contaminated EGR system components

Common misdiagnoses

Faulty EGR valve
Clogged EGR passages
Vacuum leaks
Faulty mass air flow (MAF) sensor
Faulty throttle position sensor (TPS)
Engine control module (ECM) issues
Clogged air filter
Fuel system problems

Troubleshooting steps

1. Visual Inspection
2. Check for any visible signs of damage or wear in the EGR system components, including the EGR valve, hoses, and connections
3. Look for any vacuum leaks or disconnected hoses that could affect the EGR operation
4. Check EGR Valve Operation
5. Manually operate the EGR valve (if possible) to ensure it opens and closes properly. You can apply vacuum or use a scan tool to command the valve
6. If the valve is stuck open or closed, it may need to be cleaned or replaced
7. Inspect the EGR Metering Orifice
8. The metering orifice can become clogged with carbon deposits. Remove the EGR valve and inspect the orifice for blockages
9. Clean the orifice and surrounding areas using an appropriate cleaner (like carburetor cleaner) and a soft brush
10. Check for Carbon Build-Up
11. Inspect the intake manifold and EGR passages for carbon build-up. If there is significant accumulation, it may need to be cleaned out
12. Use a suitable cleaning method, such as walnut shell blasting or chemical cleaning, to remove carbon deposits
13. Test EGR System Components
14. Use a multimeter to check the electrical connections and resistance of the EGR valve and any associated sensors
15. Ensure that the EGR temperature sensor (if equipped) is functioning correctly
16. Check for Other Codes
17. Scan for any additional trouble codes that may provide more context or indicate related issues in the EGR system or other engine components
18. Inspect the PCM (Powertrain Control Module)
19. In rare cases, the issue may be related to the PCM. Ensure that the software is up to date and that there are no known issues with the vehicle's ECU
20. Clear Codes and Test Drive
21. After performing repairs or cleaning, clear the trouble codes using a scan tool and take the vehicle for a test drive to see if the code returns
22. Consult Repair Manual
23. Refer to the vehicle's service manual for specific diagnostic procedures and specifications related to the EGR system for your make and model. If the problem persists after following these steps, it may be advisable to consult a professional mechanic for further diagnosis and repair

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Visual Inspection

2. Check for any visible signs of damage or wear in the EGR system components, including the EGR valve, hoses, and connections

3. Look for any vacuum leaks or disconnected hoses that could affect the EGR operation

4. Check EGR Valve Operation

5. Manually operate the EGR valve (if possible) to ensure it opens and closes properly. You can apply vacuum or use a scan tool to command the valve

6. If the valve is stuck open or closed, it may need to be cleaned or replaced

7. Inspect the EGR Metering Orifice

8. The metering orifice can become clogged with carbon deposits. Remove the EGR valve and inspect the orifice for blockages

9. Clean the orifice and surrounding areas using an appropriate cleaner (like carburetor cleaner) and a soft brush

10. Check for Carbon Build-Up

11. Inspect the intake manifold and EGR passages for carbon build-up. If there is significant accumulation, it may need to be cleaned out

12. Use a suitable cleaning method, such as walnut shell blasting or chemical cleaning, to remove carbon deposits

13. Test EGR System Components

14. Use a multimeter to check the electrical connections and resistance of the EGR valve and any associated sensors

15. Ensure that the EGR temperature sensor (if equipped) is functioning correctly

16. Check for Other Codes

17. Scan for any additional trouble codes that may provide more context or indicate related issues in the EGR system or other engine components

18. Inspect the PCM (Powertrain Control Module)

19. In rare cases, the issue may be related to the PCM. Ensure that the software is up to date and that there are no known issues with the vehicle's ECU

20. Clear Codes and Test Drive

21. After performing repairs or cleaning, clear the trouble codes using a scan tool and take the vehicle for a test drive to see if the code returns

22. Consult Repair Manual

23. Refer to the vehicle's service manual for specific diagnostic procedures and specifications related to the EGR system for your make and model. If the problem persists after following these steps, it may be advisable to consult a professional mechanic for further diagnosis and repair