P079A - Understanding the Transmission Range Sensor Performance Issue in 2015-2019 Ford Focus

Quick Answer

P079A means: P079A indicates a problem with the transmission range sensor performance.

Fix: Check and replace faulty components Cost: $150 - $300 Time: 90-180 minutes

Can I drive with P079A? It's advisable to address this issue promptly to avoid further transmission damage.

Common Questions

What does P079A mean and how does it affect my car?

The P079A code indicates an issue with the transmission range sensor. If this sensor fails, you may experience issues with gear shifting, leading to a rough driving experience and potentially damaging the transmission over time.

What are the most common causes of P079A and how much does it cost to fix?

Common causes include a faulty transmission range sensor or wiring issues, with repair costs ranging from $150 to $300 for sensor replacement. It's important to diagnose the problem accurately to avoid unnecessary expenses.

Can I drive my car with P079A or should I stop immediately?

While it's possible to drive with a P079A code, it's not advisable. Continuing to drive may lead to more severe transmission problems. It's best to address the issue promptly.

How can I diagnose P079A myself using GeekOBD APP?

To diagnose the P079A code, download the GeekOBD APP, conduct a scan to retrieve the code, and view any freeze frame data. This will provide context for the fault and help you pinpoint possible issues.

What vehicles are most commonly affected by P079A?

P079A is commonly seen in 2015-2019 Ford Focus models, but it can also be present in other vehicles with similar transmission systems. Always check for any recalls or service bulletins related to your specific make and model.

How can I prevent P079A from happening again?

Regular vehicle maintenance, including transmission fluid changes and electrical system checks, can help prevent issues like P079A. Keeping the transmission clean and ensuring wiring connections are secure can also mitigate risks.

What is P079A?

The P079A diagnostic trouble code refers to a problem identified in the transmission range sensor performance, which plays a crucial role in a vehicle’s transmission system. This sensor is responsible for providing the Engine Control Module (ECM) with information about the current gear selection. When this sensor fails or operates outside of its intended parameters, it can trigger the P079A code. Real-world implications of this code can lead to issues such as unexpected gear shifts, poor fuel economy, and in some cases, the vehicle may not shift into the correct gear at all. It's a problem especially noted in 2015-2019 Ford Focus models, but it can also appear in other vehicles equipped with similar transmission systems. If you notice the check engine light illuminated, it's essential to understand that while the car may still be operable, ignoring this code can lead to further mechanical problems and increased repair costs down the line. The error can stem from various factors, including wiring issues, a faulty sensor, or problems within the transmission itself, making timely diagnosis and repair critical.

System: P - Powertrain (Engine, Transmission, Emissions)

Symptoms

Common symptoms when P079A is present:

  • The check engine light remains illuminated, indicating a malfunction that needs attention.
  • Drivers may experience harsh shifting or slipping gears, making the driving experience uncomfortable and potentially unsafe.
  • Fuel economy may drop noticeably, with reports of decreased efficiency by 10-15%, impacting your overall driving cost.
  • The transmission may not engage properly, leading to a situation where the vehicle either hesitates to move or moves unexpectedly when in gear.
  • In some instances, the vehicle may enter 'limp mode,' where it limits speed and power to protect the transmission.

Possible Causes

Most common causes of P079A (ordered by frequency):

  1. The most common cause of the P079A code is a faulty transmission range sensor, with around 70% likelihood. This can happen due to wear and tear or exposure to extreme temperatures.
  2. Another cause is wiring and connector issues, often leading to poor electrical connections. Corrosion or fraying wires can disrupt the sensor's signal to the ECM.
  3. Infrequently, the problem can be attributed to internal transmission issues like valve body failures, which may require extensive repairs or replacement.
  4. Less common but serious causes include software glitches in the vehicle's transmission control module, which can be resolved with a firmware update.
  5. A rare cause could be contamination of the transmission fluid, which can affect sensor readings and overall performance.

P079A Repair Costs

Cost Breakdown by Repair Type

Transmission Range Sensor Replacement

Replacing the faulty sensor to restore proper transmission function.

  • Total: $150 - $300
  • Success rate: 90%
Wiring Repair and Maintenance

Repairing or replacing damaged wiring connections related to the sensor.

  • Total: $100 - $250
  • Success rate: 80%
Money-Saving Tips for P079A
  • Start with the most common and least expensive repairs first
  • Use GeekOBD APP to confirm diagnosis before replacing expensive parts
  • Consider preventive maintenance to avoid future occurrences
  • Compare prices for OEM vs aftermarket parts based on your needs
  • Address the issue promptly to prevent more expensive secondary damage

Diagnostic Steps

Professional P079A Diagnosis Process

Follow these systematic steps to accurately diagnose P079A. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Conduct an initial visual inspection to identify any obvious signs of damage, like corroded wires or loose connections (5-10 minutes)

Step 1: Conduct an initial visual inspection to identify any obvious signs of damage, like corroded wires or loose connections (5-10 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 2: Step 2: Use the GeekOBD APP to perform an OBD2 scan, retrieving all codes and assessing freeze frame data to understand the fault context (10-15 minutes)

Step 2: Use the GeekOBD APP to perform an OBD2 scan, retrieving all codes and assessing freeze frame data to understand the fault context (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 3: Step 3: Test the transmission range sensor and associated wiring with a multimeter to ensure they are functioning correctly (20-30 minutes)

Step 3: Test the transmission range sensor and associated wiring with a multimeter to ensure they are functioning correctly (20-30 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 4: Step 4: If repairs are made, conduct a system function test to verify the repairs and clear any codes (10-15 minutes)

Step 4: If repairs are made, conduct a system function test to verify the repairs and clear any codes (10-15 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.
Step 5: Step 5: Perform a road test to confirm that the vehicle operates normally across various conditions, ensuring the issue is resolved (15-20 minutes)

Step 5: Perform a road test to confirm that the vehicle operates normally across various conditions, ensuring the issue is resolved (15-20 minutes).

GeekOBD APP Tip: Use GeekOBD APP to monitor real-time data during this diagnostic step for accurate results and professional-grade analysis.

Important Notes

  • Always verify the repair with GeekOBD APP after completing diagnostic steps
  • Clear codes and test drive to ensure the problem is resolved
  • Address underlying causes to prevent code recurrence

Real Repair Case Studies

Case Study 1: Transmission Range Sensor Replacement on 2016 Ford Focus

Vehicle: 2016 Ford Focus, 78,000 miles

Problem: Customer reported the check engine light was on and the vehicle was experiencing harsh shifting.

Diagnosis: After scanning with the GeekOBD APP, the P079A code was retrieved. Visual inspection revealed frayed wiring leading to the sensor.

Solution: Replaced the transmission range sensor and repaired the damaged wiring.

Cost: $250 (sensor: $150, wiring repair: $100)

Result: Check engine light cleared, and the vehicle shifted smoothly during road tests.

Case Study 2: Wiring Issues Resolved in 2018 Ford Escape

Vehicle: 2018 Ford Escape, 60,000 miles

Problem: Owner noticed the engine light was on and experienced slipping gears.

Diagnosis: Utilized the GeekOBD APP to identify the P079A code. Further inspection revealed corroded connectors.

Solution: Cleaned and replaced the corroded connectors, ensuring solid electrical connections.

Cost: $180 (parts and labor)

Result: The issue was resolved, and the vehicle returned to normal operation without further issues.

Diagnose P079A

Use GeekOBD APP for professional diagnosis!

  • Real-time data monitoring
  • Advanced diagnostic features
  • Step-by-step repair guidance
  • Professional-grade analysis
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Code Information

Code: P079A
System: Powertrain (Engine, Transmission, Emissions)
Severity: HIGH
Category: Engine Codes