Engine-CodesBMW – P1477 BMW

P1477 BMW Code - Leakage Diagnostic Pump Reed Switch Did Not Open

Quick Answer

The P1477 BMW code indicates that the Leakage Diagnostic Pump Reed Switch did not open as expected. Common causes include Faulty Leakage Diagnostic Pump Reed Switch, Wiring or electrical connection issues, Evaporative emission control system leaks. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1477 BMW indicates Leakage Diagnostic Pump Reed Switch Did Not Open.
Common causes
Common causes include Faulty Leakage Diagnostic Pump Reed Switch, Wiring or electrical connection issues, Evaporative emission control system leaks.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P1477 BMW Description

The P1477 BMW code indicates that the Leakage Diagnostic Pump Reed Switch did not open as expected. This pump is responsible for maintaining the proper pressure in the fuel tank and evaporative emission control system. When the Reed Switch fails to open, it can lead to issues with the vehicle's emissions control system, potentially causing the check engine light to illuminate. If left unaddressed, this can result in failed emissions tests, reduced fuel efficiency, and even engine performance issues.

OBDII Code P1477 BMW - Leakage Diagnostic Pump Reed Switch Did Not Open
P1477 BMW Code - Leakage Diagnostic Pump Reed Switch Did Not Open

Common Causes of P1477 BMW

  1. Faulty Leakage Diagnostic Pump Reed Switch
  2. Wiring or electrical connection issues
  3. Evaporative emission control system leaks
  4. Fuel tank pressure sensor malfunction
  5. Evaporative emissions canister saturation

Symptoms of P1477 BMW

  1. Check engine light illuminated
  2. Difficulty starting the vehicle
  3. Increased fuel consumption
  4. Strong fuel odor
  5. Hissing or whistling noise from the fuel tank area

How to Fix P1477 BMW

  1. Diagnose the issue using a scan tool to confirm the P1477 code and identify the specific component causing the problem.
  2. Inspect the Leakage Diagnostic Pump Reed Switch, wiring, and connections for any damage or corrosion. Replace any faulty components.
  3. Check the evaporative emission control system for leaks and repair as necessary.
  4. Test the fuel tank pressure sensor and replace if faulty.
  5. Clear the fault code and perform a test drive to ensure the issue has been resolved.

Cost to Fix P1477 BMW

The typical repair cost for addressing a P1477 BMW code can range from $150 to $500, depending on the specific cause of the issue and the cost of replacement parts. Additional costs may include diagnostic time and labor charges. It's advisable to consult with a trusted mechanic or auto repair shop for a more accurate estimate based on your vehicle's make and model.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1477 BMW Code

1. What does the OBDII code P1477 mean on a BMW?

P1477 indicates that the Leakage Diagnostic Pump (LDP) reed switch did not open, suggesting a potential issue in the evaporative emissions control system.

2. What are the common symptoms of code P1477 on a BMW?

Symptoms may include the check engine light turning on, a possible fuel odor, and, in some cases, reduced fuel efficiency or difficulty passing emissions tests.

3. What causes the P1477 code to appear on a BMW?

Common causes include a faulty leakage diagnostic pump, a stuck or damaged reed switch, wiring issues, or a problem with the EVAP system, such as a leak.

4. Can a loose gas cap trigger the P1477 code on a BMW?

While a loose gas cap is a common cause of EVAP-related codes, it is less likely to cause P1477 specifically. However, it’s worth checking the gas cap as part of the diagnostic process.

5. How do I diagnose the P1477 code on my BMW?

Start by inspecting the Leakage Diagnostic Pump and its reed switch for damage. Check the wiring and connectors for corrosion or disconnections, and use a smoke machine to test for EVAP leaks if necessary.

6. Can I drive my BMW with the P1477 code?

Yes, you can drive with the P1477 code, but it’s best to address the issue promptly to avoid potential EVAP system damage or failing an emissions test.

7. How do I fix the P1477 code on a BMW?

Repairs may involve replacing the Leakage Diagnostic Pump, repairing wiring or connectors, or addressing any leaks in the EVAP system.

8. How much does it cost to fix the P1477 code on a BMW?

The repair cost can vary but typically ranges from $150 to $500, depending on whether the issue is with the pump, wiring, or other EVAP components.

9. Can a faulty reed switch alone cause the P1477 code?

Yes, a malfunctioning reed switch in the Leakage Diagnostic Pump can directly cause the P1477 code by failing to open as expected.

10. Will clearing the P1477 code with a scanner fix the problem?

Clearing the code may turn off the check engine light temporarily, but the underlying issue must be resolved to prevent the code from returning.

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