how to fix P0171 and P0174 codes on Tesla Model S Plaid/Refresh (2021-present)

Tesla Model S Plaid/Refresh (2021-present)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

Error Code: P0171, P0174

3 min read

548 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix P0171 and P0174 codes on Tesla Model S Plaid. Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Error Code

P0171, P0174

Affected Component

Engine

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow the engine to cool before inspecting the intake system.

Symptoms

•Check engine light illuminated
•Reduced engine performance
•Rough idle or stalling
•Increased fuel consumption
•Poor acceleration response

Diagnostic Steps

1
Scan the vehicle using an OBD-II scanner to confirm P0171 and P0174 codes.
2
Inspect the air intake system for any vacuum leaks or damaged hoses.
3
Check the fuel system pressure to ensure it meets specifications.
4
Inspect the mass airflow sensor (MAF) for contamination or faults.
5
Examine the fuel injectors for proper operation and ensure there are no blockages.
6
Review the engine control unit (ECU) for any software updates or faults.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Smoke machine
•MAF cleaner
•Fuel pressure gauge
•Injector cleaning kit (optional)

Parts Required

•Replacement vacuum hoses (if necessary)
•MAF sensor (if faulty)
•Fuel filter (if pressure is low)
•Fuel injectors (if clogged or malfunctioning)

Related Faults

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Diagnostic Steps

1
Scan the vehicle using an OBD-II scanner to confirm P0171 and P0174 codes.
2
Inspect the air intake system for any vacuum leaks or damaged hoses.
3
Check the fuel system pressure to ensure it meets specifications.
4
Inspect the mass airflow sensor (MAF) for contamination or faults.
5
Examine the fuel injectors for proper operation and ensure there are no blockages.
6
Review the engine control unit (ECU) for any software updates or faults.

Solution

1. Preparation

Gather tools and parts needed for the repair.
Disconnect the negative terminal of the battery to ensure safety during repairs.

2. Inspect and Repair Vacuum Leaks

Sub-steps:
- Visually inspect all intake hoses and connections for cracks or loose fittings.
- Use a smoke machine to detect any hidden vacuum leaks in the intake system.
- Replace any damaged hoses or gaskets to ensure a tight seal.

3. Clean the Mass Airflow Sensor

Tools Required: MAF cleaner, soft cloth
Sub-steps:
- Locate the MAF sensor in the air intake duct.
- Disconnect the electrical connector and remove the sensor.
- Spray MAF cleaner onto the sensor elements and allow it to dry completely.
- Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel System Pressure

Tools Required: Fuel pressure gauge
Sub-steps:
- Connect the fuel pressure gauge to the fuel rail test port.
- Turn the ignition on (do not start the engine) to check for fuel pressure.
- Compare the reading with manufacturer specifications. If pressure is low, inspect the fuel pump and filter.
- Replace the fuel pump or filter if necessary.

5. Inspect Fuel Injectors

Tools Required: Injector cleaning kit (if needed)
Sub-steps:
- Remove the fuel rail to access the injectors.
- Inspect each injector for clogs or leaks.
- Clean the injectors using an injector cleaning kit or replace them if they are faulty.