P0120 Mercedes-Benz Code - Throttle/Pedal Position Sensor/Switch A Circuit Malfunction
Quick Answer
The throttle position sensor (TPS) responds to the accelerator pedal movement. Common causes include Faulty Throttle Position Sensor, Throttle Position Sensor circuit is open or shorted, Throttle Position Sensor poor electrical connection. 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
- P0120 Mercedes-Benz indicates Throttle/Pedal Position Sensor/Switch A Circuit Malfunction .
- Common causes
- Common causes include Faulty Throttle Position Sensor, Throttle Position Sensor circuit is open or shorted, Throttle Position Sensor poor electrical connection.
- 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.
Code P0120 Mercedes-Benz Description
Idle position of the throttle valve is determined by the ECM receiving the signal from the throttle position sensor. This sensor controls engine operation such as fuel cut. On the other hand, the Wide open and closed throttle position switch, which is built into the throttle position sensor unit, is not used for engine control.
What are the Possible Causes of the DTC P0120 Mercedes-Benz?
- Faulty Throttle Position Sensor
- Throttle Position Sensor circuit is open or shorted
- Throttle Position Sensor poor electrical connection
How to Fix the DTC P0120 Mercedes-Benz?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0120 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P0120 Mercedes-Benz code?
Need more information on how to fix the P0120 Mercedes-Benz code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0120 Mercedes-Benz code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0120 Mercedes-Benz Code
1. What does the OBDII code P0120 indicate on a Mercedes-Benz?
The P0120 code on a Mercedes-Benz indicates that there is a malfunction in the Throttle/Pedal Position Sensor/Switch "A" Circuit. This sensor is crucial for determining the throttle position and communicating it to the engine control module (ECM).
2. What are the common symptoms of code P0120 in a Mercedes-Benz?
Common symptoms include engine stalling, erratic throttle response, the engine going into limp mode, and poor acceleration. The check engine light will also be illuminated.
3. What can cause the P0120 code to appear on a Mercedes-Benz?
Possible causes include a faulty throttle position sensor, poor electrical connections at the throttle position sensor, a damaged throttle body, or issues with the ECM itself.
4. How is the P0120 code diagnosed in a Mercedes-Benz?
Diagnosis typically involves using a scan tool to read the fault code and examining the throttle position sensor and its related wiring for signs of damage or disconnection. The sensor's performance may also be tested using a voltmeter.
5. What are the potential repairs for fixing a P0120 code on a Mercedes-Benz?
Repairs can range from cleaning the throttle body, repairing or replacing damaged wires or connectors, replacing the throttle position sensor, or in some cases, replacing the throttle body or ECM.
6. Is it safe to drive a Mercedes-Benz with a P0120 code?
While the vehicle can often still be driven, doing so with a malfunctioning throttle position sensor can lead to reduced performance and potentially unsafe driving conditions, such as unexpected stalling or impaired acceleration.
7. How much does it typically cost to resolve a P0120 code in a Mercedes-Benz?
The cost can vary widely depending on the specific repair needed. Replacing a throttle position sensor can cost between $150 and $350, whereas more extensive repairs like replacing the throttle body or ECM can cost upwards of $500 to $1000.
8. Can a faulty battery or alternator trigger the P0120 code in a Mercedes-Benz?
While a faulty battery or alternator is not a direct cause of the P0120 code, they can contribute to voltage irregularities that may affect the throttle position sensor’s performance, potentially leading to this error code.
9. What is the importance of the Throttle/Pedal Position Sensor in a Mercedes-Benz?
The throttle/pedal position sensor plays a critical role in the vehicle's engine management system by informing the ECM about the position of the throttle or accelerator pedal, which helps in adjusting air intake, fuel flow, and overall engine performance.
10. How can I prevent the P0120 code on my Mercedes-Benz?
Regular maintenance of the vehicle’s engine and electrical systems, including checking and cleaning the throttle body and ensuring all sensors are connected and functioning properly, can help prevent this and other engine-related codes.
Discuss the causes and fixes for P0120 Mercedes-Benz OBDII Code
Code P0120 Mercedes-Benz comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
