The P1407 code is a manufacturer-specific powertrain code indicating a detected fault in the Exhaust Gas Recirculation (EGR) system. Because it is manufacturer-specific, its exact definition depends entirely on the vehicle application.
This code identifies a detected system performance or electrical condition, not necessarily a failed EGR valve. Proper diagnosis requires verifying the exact factory definition and testing the relevant EGR components and circuits.
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Key Takeaways
- The P1407 code is manufacturer-specific, indicating an EGR system flow, air intrusion, or sensor circuit fault depending on the vehicle.
- Possible causes include carbon buildup, a failed EGR valve, faulty position sensors, or vacuum and electrical circuit issues.
- Symptoms typically include an illuminated Check Engine Light, rough idle, and potentially failed emissions monitors.
- Diagnosis requires confirming the exact factory definition and testing the EGR valve, sensors, and control circuits.
- Repairs depend on the confirmed fault and may involve cleaning carbon deposits, replacing the EGR valve, or repairing wiring.
P1407 Code Description and Implications
P1407 is a manufacturer-specific code. Its exact definition depends entirely on the vehicle application.
Some Ford applications: The code indicates an “EGR Flow Out of Self-Test Range” fault, meaning the Powertrain Control Module (PCM) did not detect the expected change in exhaust gas flow when commanding the EGR valve open during a self-test.
Certain General Motors (GM) applications: The code indicates “EGR Air Intrusion in Exhaust Supply,” where the PCM detects unmetered air entering the EGR system or exhaust supply.
Some Honda and Acura applications: The code may relate to an “EGR Valve Lift Sensor Circuit Low Input” or insufficient EGR flow detected during operation.
Common Causes of the P1407 Code
Several conditions can trigger this manufacturer-specific malfunction code. Identifying the exact cause requires electrical and mechanical testing.
- Carbon buildup restricting the EGR valve pintle or exhaust passages.
- A failed or mechanically stuck EGR valve.
- A faulty EGR valve position sensor or EGR temperature sensor providing inaccurate data.
- Vacuum leaks in the EGR control hoses on vacuum-operated systems.
- Broken, chafed, or shorted wiring in the EGR valve control or sensor circuits.
- Corroded, loose, or contaminated electrical connectors at the EGR valve or PCM.
Symptoms Associated With P1407
Symptoms vary depending on the specific system design and the underlying fault condition.
- Illuminated Check Engine Light.
- Rough idle, engine stalling, or hesitation during acceleration due to incorrect EGR flow.
- Engine knocking or pinging under load from elevated combustion temperatures.
- The vehicle may fail an emissions inspection due to an incomplete EGR monitor or high NOx levels.
Diagnosing the P1407 Trouble Code
Diagnosis must begin by confirming the exact factory definition and inspecting the physical system components.
- Verify the exact manufacturer definition and locate the wiring or vacuum diagram for the specific EGR system.
- Visually inspect the EGR valve, passages, vacuum hoses, and electrical connectors for carbon buildup, cracks, or damage.
- Use a scan tool to monitor live EGR position sensor data or commanded EGR duty cycle while commanding the valve.
- For vacuum-operated systems, use a hand vacuum pump to apply vacuum directly to the EGR valve diaphragm.
- Use a digital multimeter to test the EGR position sensor reference, signal, and ground circuits for opens or shorts.
Repairing the P1407 Issue
Repairs depend entirely on the confirmed root cause of the system malfunction.
- If carbon buildup is found, clean the EGR valve pintle, intake manifold EGR ports, and exhaust supply tubes.
- If the EGR valve fails to hold vacuum or respond to electrical commands, replace it using a correct component.
- If the EGR position sensor or wiring fails electrical testing, repair the wiring or replace the sensor.
- Replace any cracked, brittle, or melted vacuum hoses associated with the EGR system.
Cost Considerations for P1407 Repairs
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Cleaning carbon deposits from EGR passages is generally less expensive than replacing an electronically controlled EGR valve assembly, which may require PCM relearn procedures.
Prevention Strategies for Future Occurrences
While electrical and mechanical failures are not always preventable, some practices can reduce the risk of EGR system issues.
- Using high-quality fuel and adhering to recommended oil change intervals can help reduce excessive carbon accumulation in the intake.
- Inspecting exposed vacuum hoses and electrical connectors can help identify developing damage from heat exposure or chafing.
Troubleshooting Tips and Best Practices
Always consult the exact manufacturer service information for your vehicle’s diagnostic flowchart and expected live data values.
- Do not assume the EGR valve is faulty simply because the code points to the EGR system; restricted passages and vacuum leaks must be ruled out first.
- Verify technical service bulletins for your specific make and model, as some manufacturers issue updated EGR valve designs or revised PCM software calibrations.
More OBD-II Codes
| P1400 | P1401 | P1403 | P1404 |
| P1405 | P1406 | P1408 | P1409 |
| P1410 | P1415 | P1416 | P1418 |
| P1420 | P1421 | P1423 | P1431 |
| P1432 | P1433 | P1441 | P1444 |
| P1445 | P1446 | P1447 | P1448 |
Frequently Asked Questions
Is the P1407 code generic or manufacturer-specific?
No. P1407 is a manufacturer-specific code. Its exact definition varies by vehicle make, indicating an EGR flow, air intrusion, or sensor circuit fault.
Can I drive my car with a P1407 code?
It depends on the symptoms. If the engine runs normally, it may be safe for short trips. However, incorrect EGR flow can cause knocking, rough idle, or increased emissions.
Will cleaning the EGR valve fix a P1407 code?
It might. If the code was triggered by carbon buildup restricting the EGR passages or valve pintle, a thorough cleaning may resolve the issue and restore proper flow.
Can a vacuum leak trigger the P1407 code?
Yes. On applications using a vacuum-operated EGR valve, a cracked or disconnected vacuum hose will prevent the valve from opening, causing a flow or self-test failure.
Will a P1407 code cause an emissions test failure?
Yes. A malfunctioning EGR system prevents the OBD-II monitor from completing its self-tests and can increase NOx emissions, causing an automatic failure during an OBD-II inspection.
What Should You Do About the P1407 Code?
Confirm the exact factory definition for your specific vehicle application. Follow the applicable manufacturer diagnostic procedure to test the relevant EGR system components, sensors, and vacuum or electrical circuits.
Repair or replace the confirmed failed component or clear the identified carbon restriction, then retest the system to ensure proper operation.
