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P1407 – EGR Pressure Feedback Sensor Circuit Low

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Understanding the P1407 EGR System Malfunction Code

The P1407 is a diagnostic trouble code (DTC) for "EGR Flow Insufficient Detected". This is a generic powertrain code, which means it applies to all makes and models of vehicles (1996-newer), although specific repair steps may vary depending on the model.

In our workshop, we've seen the P1407 code pop up quite frequently, especially on European makes like Volvo, BMW, and Audi. Just last week, a customer brought in their 2012 Volvo V70 with the check engine light on. When we scanned it, sure enough, P1407 came up. We dug a little deeper and found the EGR valve was clogged up with carbon deposits. A good cleaning took care of it, but sometimes the valve needs to be replaced entirely. We've also run into this code on some BMW 3-series and Audi A4 models, usually due to failed EGR temperature sensors or stuck open valves. It seems to be a common issue on these cars once they get some miles on them. Whenever we see P1407, we know to start by checking the EGR system components, as that's almost always the culprit on the European vehicles we service.

How Serious is the P1407 Code?

The P1407 code is moderately severe and should be addressed soon, but it is typically safe to continue driving the vehicle in the short term. However, you may notice reduced engine performance and fuel efficiency. If ignored for too long, this issue can potentially lead to engine damage due to increased combustion chamber temperatures and incomplete fuel burning.

It's best to diagnose and repair this issue as soon as possible to prevent potential engine damage and restore proper vehicle performance. If the check engine light is flashing, this indicates a severe misfire that can quickly overheat the catalytic converter, so pull over and have the vehicle towed to prevent damage.

Technical Details of Code P1407

The P1407 code is set when the powertrain control module (PCM) detects that the actual exhaust gas recirculation (EGR) flow is less than the commanded EGR flow. The EGR system redirects a small amount of exhaust gas back into the intake manifold to lower combustion temperatures and reduce NOx emissions.

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The PCM uses inputs from various sensors like the EGR valve position sensor, differential pressure feedback EGR (DPFE) sensor, manifold absolute pressure (MAP) sensor, and mass air flow (MAF) sensor to calculate the actual and desired EGR flow rates. If a discrepancy is detected between these two values, the P1407 trouble code is triggered.

Common Causes of Code P1407

There are several potential causes for the P1407 code to be set:

  1. Clogged or stuck open EGR valve
  2. Leaking or disconnected vacuum lines to the EGR valve
  3. Malfunctioning EGR valve position sensor or DPFE sensor
  4. Clogged EGR passages or tubes
  5. Faulty PCM (rare)

Diagnosing the P1407 Code

To properly diagnose the root cause of the P1407 code, follow these steps:

  1. Connect an OBD-II scanner and record all stored trouble codes and freeze frame data.
  2. Visually inspect the EGR valve, vacuum lines, and wiring for obvious damage or loose connections.
  3. Test the EGR valve for proper operation using a vacuum pump. The valve should hold vacuum and open/close smoothly.
  4. Check the resistance of the EGR position sensor (should be 1-8 kΩ) and the voltage of the DPFE sensor (should vary with EGR flow).
  5. Inspect the EGR passages and tubes for clogs or excessive carbon buildup.
  6. If no issues are found, suspect a faulty PCM, but this is rare and should be diagnosed by a professional.

Repairing Code P1407

The specific repair for the P1407 code will depend on the diagnosed root cause:

  1. For a clogged EGR valve or passages, remove the valve and clean it thoroughly with carburetor cleaner. Soak the passages if needed to remove heavy carbon deposits.
  2. For a stuck open EGR valve, replace the valve assembly.
  3. For damaged vacuum lines, repair or replace as needed. Ensure all connections are secure.
  4. For a faulty EGR position sensor or DPFE sensor, replace the sensor.
  5. For a faulty PCM, have it reprogrammed or replaced by a professional.

After repairs are complete, clear the trouble codes and perform a test drive to verify the fix. The code should not re-trigger if repairs were successful.

Preventing EGR System Issues

To help prevent EGR system malfunctions and the P1407 code from occurring, follow these tips:

Cost of Repairing Code P1407

The cost to diagnose and repair the P1407 code can vary depending on the root cause and labor rates, but here are some general estimates:

Note that these are just rough estimates and actual costs may be higher or lower depending on vehicle make, model, and location.

Some other issues and codes that may appear along with the P1407 include:

If any of these related codes are present, be sure to diagnose and repair them as well for optimal engine performance and emissions control.

Frequently Asked Questions About P1407

What does the P1407 code mean?

The P1407 code stands for “EGR Flow Insufficient Detected.” It indicates that the powertrain control module (PCM) has detected that the actual exhaust gas recirculation (EGR) flow is less than the commanded EGR flow.

What are the symptoms of the P1407 code?

Common symptoms include:

What causes the P1407 code?

Potential causes include:

Is it safe to drive with a P1407 code?

It is typically safe to drive in the short term, but you may notice reduced performance and fuel economy. If ignored for too long, it can potentially lead to engine damage. If the check engine light is flashing, do not drive the vehicle.

How do you diagnose the P1407 code?

Diagnosis steps include:

  1. Scan for codes and document freeze frame data
  2. Visually inspect the EGR system for obvious issues
  3. Test the EGR valve for proper operation
  4. Check the EGR position sensor and DPFE sensor
  5. Inspect the EGR passages for clogs
  6. Suspect a faulty PCM if no other issues are found

How do you fix the P1407 code?

Repairs will depend on the diagnosed cause:

How much does it cost to repair the P1407 code?

Repair costs can range from $50-$500 depending on the issue:

Can I diagnose the P1407 code myself?

Diagnosing the P1407 code requires intermediate auto repair skills. You need a scan tool to read codes and test sensors, as well as the ability to visually inspect components and trace vacuum lines. It’s best left to professionals if you are a novice.

Can a clogged catalytic converter cause the P1407 code?

No, a clogged catalytic converter will not directly cause the P1407 code, as it deals with insufficient EGR flow. However, other EGR issues can lead to unburned fuel entering the exhaust and damaging the catalytic converter over time.

Can a vacuum leak cause the P1407 code?

Yes, a vacuum leak in the lines going to the EGR valve can cause insufficient EGR flow and trigger the P1407 code. Inspect the vacuum lines for cracks, kinks, or loose connections.

Can a dirty air filter cause the P1407 code?

No, a dirty air filter will not directly cause the P1407 code. However, a severely restricted air filter can cause a variety of drivability problems and should be replaced if dirty.

Can a bad O2 sensor cause the P1407 code?

No, a bad O2 sensor will not directly trigger the P1407 code. The O2 sensors monitor the exhaust gases and provide feedback to the PCM to adjust the air/fuel mixture. They are not directly involved in EGR operation.

Can low coolant cause the P1407 code?

No, low coolant will not cause the P1407 code, as the coolant system is not directly related to EGR operation. However, low coolant can cause overheating and potential engine damage if ignored.

Can a bad thermostat cause the P1407 code?

No, a bad thermostat will not trigger the P1407 code. The thermostat regulates coolant flow and engine operating temperature but is not involved in the EGR system.

Can a bad mass air flow sensor cause the P1407 code?

Possibly. The MAF sensor measures incoming air flow, which the PCM uses to calculate EGR flow rates. A faulty MAF sensor can provide incorrect data and potentially trigger the code, but it is not the most common cause.

Will disconnecting the battery clear the P1407 code?

Disconnecting the battery will clear the P1407 code temporarily, but it will come back if the underlying issue is not fixed. It’s best to properly diagnose and repair the problem.

How often should the EGR system be cleaned?

EGR system cleaning is typically recommended every 50,000 miles or as needed. Carbon buildup is common and can clog the valve and passages over time. Regular cleaning can help prevent issues.

Can I replace just the EGR valve gasket?

In most cases, no. If the EGR valve has failed, it is best to replace the entire valve assembly, as the gasket is often integrated or the valve itself is damaged. Attempting to reuse an old valve is likely to cause repeat failures.

What are the most common EGR codes?

The most common EGR related codes include:

How do I prevent EGR system issues?

To prevent EGR system issues and the P1407 code:

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