Quick Answer
P2120 means: DTC P2120 indicates an issue with the throttle position sensor, affecting engine performance.
Can I drive with P2120? Immediate attention is recommended to avoid further engine damage.
Common Questions
What does P2120 mean and how does it affect my car?
The P2120 code indicates a problem with your vehicle's throttle position sensor, which affects how your engine controls power and fuel efficiency. If not fixed, you might experience performance issues, stalling, and reduced fuel economy.
What are the most common causes of P2120 and how much does it cost to fix?
The most common causes include a faulty throttle position sensor, damaged wiring, or issues with the engine control module. Repair costs can range from $150 for sensor replacement to $200 for wiring repairs.
Can I drive my car with P2120 or should I stop immediately?
It's best to address the P2120 code immediately. Driving with this code can lead to poor engine performance and potential safety hazards due to loss of throttle control.
How can I diagnose P2120 myself using GeekOBD APP?
Download the GeekOBD APP and connect your OBD2 scanner. Run a full scan to check for DTCs and freeze frame data. Focus on the TPS readings under different throttle positions to identify inconsistencies.
What vehicles are most commonly affected by P2120?
Commonly affected vehicles include the 2007-2013 Chevrolet Malibu, 2010-2015 Honda Accord, and various models from Ford and Toyota. Always check for any recalls or service bulletins related to the TPS.
How can I prevent P2120 from happening again?
Regular maintenance, including checking and cleaning connections, can help prevent P2120. Ensure that the vehicle's electrical system is in good condition, and consider periodic inspections of the throttle body and TPS.
What is P2120?
The diagnostic trouble code (DTC) P2120 signifies a problem with the throttle position sensor (TPS), a critical component in modern vehicles that plays a vital role in engine management. It is particularly common in vehicles such as the 2007-2013 Chevrolet Malibu and the 2010-2015 Honda Accord. This code can arise when the TPS voltage signals are abnormal; they may be too high, too low, or erratic. The throttle position sensor monitors the position of the throttle plate, which is crucial for the engine control unit (ECU) to manage fuel injection and air intake. When the TPS fails or communicates incorrect data, it can severely affect engine performance, leading to symptoms like stalling, hesitation during acceleration, or even triggering the check engine light. If left unaddressed, this can lead to increased fuel consumption and may cause further engine issues. Additionally, the P2120 code could indicate wiring or connection problems, making it essential to check these components alongside the sensor itself. As the throttle position sensor is integral to the drive-by-wire system in many vehicles, the malfunction can lead to a loss of power and a less responsive throttle, impacting overall driving safety.
System: P - Powertrain (Engine, Transmission, Emissions)
Symptoms
Common symptoms when P2120 is present:
- The check engine light remains illuminated, signaling a problem that requires immediate attention.
- You may experience engine hesitation during acceleration, making it difficult to maintain speed or smoothly increase power.
- Fuel economy can drop significantly, often by 10-15%, leading to more frequent trips to the gas station.
- Unusual engine stalling can occur, especially at low speeds or when coming to a stop, which can be dangerous.
- You might notice a lack of throttle response, where pressing the accelerator does not result in expected power increase.
Possible Causes
Most common causes of P2120 (ordered by frequency):
- The most common cause of the P2120 code is a faulty throttle position sensor, accounting for about 60% of cases. This sensor can wear out or fail due to exposure to heat and contaminants.
- Another common cause is damaged wiring or poor connections related to the TPS. This can often occur from corrosion or physical damage, affecting the sensor's signal.
- Issues with the engine control module (ECM) can also cause this code, as the ECM may misinterpret the TPS signals. Regular updates and checks can prevent this issue.
- Less common, but serious, is the possibility of a vacuum leak in the intake system, which can cause erratic TPS readings and impact performance.
- Rarely, a failing throttle body can also trigger the P2120 code, as it may not open or close correctly, leading to TPS signal issues.
P2120 Repair Costs
Cost Breakdown by Repair Type
Throttle Position Sensor Replacement
Replacing the faulty TPS with a new part to restore functionality.
- Total: $150 - $300
- Success rate: 90%
Wiring Repair
Repairing or replacing damaged wiring or connectors associated with the TPS.
- Total: $100 - $200
- Success rate: 85%
Money-Saving Tips for P2120
- 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 P2120 Diagnosis Process
Follow these systematic steps to accurately diagnose P2120. Each step builds on the previous one to ensure accurate diagnosis.
Step 1: Perform an initial visual inspection, checking for damaged wiring, loose connections, or signs of corrosion around the TPS (5-10 minutes)
Step 2: Use the GeekOBD APP to perform an OBD2 scan, retrieving all codes and freeze frame data to understand the fault context better (10-15 minutes)
Step 3: Conduct component testing with a multimeter to measure the TPS voltage and ensure it operates within specified parameters (20-30 minutes)
Step 4: Run a system function test to confirm proper operation after repairs, and clear any error codes stored in the ECU (10-15 minutes)
Step 5: Complete a road test under various driving conditions to verify repair success and ensure the vehicle operates smoothly (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 in a 2012 Chevrolet Malibu
Vehicle: 2012 Chevrolet Malibu, 85,000 miles
Problem: Customer reported engine stalling and hesitation during acceleration.
Diagnosis: After running a scan, we found the P2120 code along with erratic TPS voltage readings.
Solution: We replaced the throttle position sensor and reconnected any loose wiring.
Cost: $220 (parts: $120, labor: $100)
Result: The vehicle's performance improved significantly, with no further issues.
Case Study 2: Wiring Repair for P2120 in a 2011 Honda Accord
Vehicle: 2011 Honda Accord, 70,000 miles
Problem: Customer experienced a check engine light and poor acceleration.
Diagnosis: The GeekOBD APP scan confirmed the P2120 code with signs of wiring damage.
Solution: We repaired the damaged wiring and ensured all connections were secure.
Cost: $180 (parts: $80, labor: $100)
Result: Post-repair, the vehicle ran smoothly, and the check engine light was resolved.