Quick Answer
P2138 means: P2138 indicates a throttle position sensor issue, affecting engine performance.
Can I drive with P2138? Immediate attention is advised to prevent further engine damage.
Common Questions
What does P2138 mean and how does it affect my car?
P2138 indicates a problem with the throttle position sensor circuit, which can lead to poor engine performance, hesitation, and reduced fuel efficiency. If left unaddressed, it may cause more severe engine issues.
What are the most common causes of P2138 and how much does it cost to fix?
The most common causes include a faulty throttle position sensor, damaged wiring, or a dirty throttle body. Repair costs typically range from $100 to $600 depending on the issue.
Can I drive my car with P2138 or should I stop immediately?
While you may be able to drive, it is not recommended as it can lead to unsafe driving conditions and further engine damage. It's best to address the issue promptly.
How can I diagnose P2138 myself using GeekOBD APP?
Using the GeekOBD APP, connect to your vehicle's OBD2 port, read the diagnostic codes, and analyze freeze frame data to understand when the issue occurs. Follow the diagnostic steps to locate the problem.
What vehicles are most commonly affected by P2138?
P2138 is commonly seen in vehicles like the 2015-2018 Honda Civic, 2013-2016 Dodge Dart, and 2014-2017 Chevrolet Malibu. Always check for recalls or technical service bulletins (TSBs) related to this code.
How can I prevent P2138 from happening again?
Regular maintenance, including cleaning the throttle body and checking electrical connections, can help prevent P2138. Using the GeekOBD APP to monitor your vehicle's performance can also aid early detection of issues.
What is P2138?
The diagnostic trouble code (DTC) P2138 indicates a problem with the throttle position sensor circuit, specifically a range or performance issue. This code is often triggered when the Engine Control Module (ECM) detects a discrepancy in the signal from the throttle position sensor(s) compared to expected values. In vehicles like the 2015-2018 Honda Civic, this can manifest as a loss of acceleration, poor engine performance, or the vehicle going into 'limp mode' to protect the engine. The throttle position sensors are crucial for the engine's air-fuel mixture management and overall performance, which means that issues in this system can lead to reduced power, increased fuel consumption, and potentially dangerous driving conditions. If left unaddressed, this code can lead to increased wear on the engine components due to improper fuel delivery, and in some severe cases, it may cause damage to the catalytic converter. Understanding this code is essential for maintaining your vehicle's efficiency and safety.
System: P - Powertrain (Engine, Transmission, Emissions)
Symptoms
Common symptoms when P2138 is present:
- The check engine light is illuminated, often remaining on until the issue is resolved.
- Engine hesitates during acceleration, making it difficult to maintain speed or merge into traffic safely.
- Fuel economy decreases, typically by 10-15%, leading to increased fuel expenses.
- Unresponsive throttle when pressing the accelerator pedal, resulting in delayed engine response.
- Strange engine noises or vibrations may occur, especially when trying to accelerate.
Possible Causes
Most common causes of P2138 (ordered by frequency):
- The most common cause of P2138 is a faulty throttle position sensor, which has an estimated likelihood of 60%. This sensor can wear out over time, leading to inaccurate readings.
- A damaged or corroded wiring harness can also trigger this code. Issues with the wiring are responsible for about 25% of cases, where the sensor itself may be fine, but the electrical connection is compromised.
- A dirty throttle body can affect sensor performance, and regular cleaning can prevent this issue. This is a common preventative tip for about 10% of cases.
- Less common but serious causes include a malfunctioning ECM, which may require reprogramming or replacement if diagnosed (approximately 3%).
- Rarely, a mechanical issue within the throttle body assembly can cause this code, usually needing complete replacement.
P2138 Repair Costs
Cost Breakdown by Repair Type
Throttle Position Sensor Replacement
Replacing the faulty throttle position sensor with an OEM part for optimal performance.
- Total: $150 - $300
- Success rate: 90%
Wiring Harness Repair
Repairing or replacing damaged wiring harnesses related to the throttle position sensor.
- Total: $100 - $250
- Success rate: 85%
ECM Reprogramming
Reprogramming the ECM if it is determined to be malfunctioning.
- Total: $200 - $600
- Success rate: 75%
Money-Saving Tips for P2138
- 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 P2138 Diagnosis Process
Follow these systematic steps to accurately diagnose P2138. Each step builds on the previous one to ensure accurate diagnosis.
Step 1: Initial visual inspection - Look for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes)
Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes)
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the throttle position sensor and wiring (20-30 minutes)
Step 4: System function test - Verify proper operation after repairs and clear codes using the GeekOBD APP (10-15 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success (15-20 minutes)
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: Throttle Position Sensor Replacement on 2016 Honda Civic
Vehicle: 2016 Honda Civic, 50,000 miles
Problem: Customer reported check engine light and engine hesitating during acceleration.
Diagnosis: Diagnostic scan revealed code P2138. Visual inspection showed a faulty throttle position sensor.
Solution: Replaced throttle position sensor with OEM part.
Cost: $250 (sensor $150, labor $100)
Result: Issue resolved, vehicle performance returned to normal.
Case Study 2: Wiring Harness Repair on 2015 Dodge Dart
Vehicle: 2015 Dodge Dart, 45,000 miles
Problem: Check engine light and unresponsive throttle when accelerating.
Diagnosis: P2138 was triggered due to damaged wiring in the throttle sensor circuit.
Solution: Repaired wiring harness and re-secured connections.
Cost: $150 (labor $100, materials $50)
Result: Vehicle performance improved, no further issues reported.