AutoCodes – Mercedes-Benz – P2123 Mercedes-Benz

P2123 Mercedes-Benz Code - Throttle/Pedal Position Sensor/Switch 'D' Circuit High

Quick Answer

This fault code is stored in the Engine Control Module (ECM) when a fault is detected with the circuit monitoring throttle and accelerator pedal position. Common causes include Faulty Accelerator Pedal Position Sensor, Accelerator Pedal Position Sensor harness is open or shorted, Accelerator Pedal Position Sensor circuit 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
P2123 Mercedes-Benz indicates Throttle/Pedal Position Sensor/Switch 'D' Circuit High.
Common causes
Common causes include Faulty Accelerator Pedal Position Sensor, Accelerator Pedal Position Sensor harness is open or shorted, Accelerator Pedal Position Sensor circuit 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.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 13,217
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Sep 08, 2019
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Code P2123 Mercedes-Benz Description

This fault code is stored in the Engine Control Module (ECM) when a fault is detected with the circuit monitoring throttle and accelerator pedal position. Both circuits are closely monitored for plausibility checks. The ECM can easily identify erroneous data by monitoring both circuits for an inconsistency between the throttle position sensor voltage and the accelerator pedal position sensor voltage. Normally potentiometers are used for both sensor circuits, however some manufacturers may use a hall effect sensor with a varying frequency depending on position. Another feature of modern vehicles is using multiple sensors for redundancy and fault analysis. This is where a technician would see data for accelerator pedal position sensor 1 and 2 or throttle position sensor 1 and 2. The voltages from these components can be inversely proportional or a stepped waveform with only output half the output of the other.
OBDII Code P2123 Mercedes-Benz - Throttle/Pedal Position Sensor/Switch 'D' Circuit High - AutoCodes.com
P2123 Mercedes-Benz Code - Throttle/Pedal Position Sensor/Switch 'D' Circuit High

What are the Possible Causes of the DTC P2123 Mercedes-Benz?

  • Faulty Accelerator Pedal Position Sensor
  • Accelerator Pedal Position Sensor harness is open or shorted
  • Accelerator Pedal Position Sensor circuit poor electrical connection

How to Fix the DTC P2123 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.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2123 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 P2123 Mercedes-Benz code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P2123 Mercedes-Benz Code

1. What are common symptoms of OBDII code P2123 in a Mercedes-Benz related to the Throttle/Pedal Position Sensor/Switch 'D' Circuit High?

- Common symptoms may include a check engine light, reduced engine power, rough idling, and unresponsive acceleration.

2. What are possible causes of the P2123 code in a Mercedes-Benz?

- The P2123 code can be caused by a faulty throttle position sensor, wiring issues, a defective pedal position sensor, or a problem with the engine control module.

3. How serious is the Throttle/Pedal Position Sensor/Switch 'D' Circuit High issue in a Mercedes-Benz?

- This issue can affect the performance and drivability of the vehicle, potentially leading to safety concerns. It is recommended to address the problem promptly.

4. Can I continue driving my Mercedes-Benz with the P2123 code present?

- It is not recommended to continue driving with the P2123 code as it can lead to further damage or safety risks. It is best to have the issue diagnosed and repaired as soon as possible.

5. How can I diagnose the cause of the P2123 code in my Mercedes-Benz?

- Diagnosing the P2123 code typically involves using a diagnostic scanner to retrieve the specific fault codes, inspecting the throttle and pedal position sensors, and checking the wiring for any issues.

6. What are some repair tips for fixing the Throttle/Pedal Position Sensor/Switch 'D' Circuit High issue in a Mercedes-Benz?

- Repair tips may include checking and cleaning the throttle body, inspecting and repairing any damaged wiring, replacing the throttle or pedal position sensor if necessary, and resetting the engine control module.

7. Can I reset the P2123 code in my Mercedes-Benz using an OBDII scanner?

- Yes, you can use an OBDII scanner to reset the P2123 code after addressing the underlying issue. However, if the problem persists, the code is likely to reappear.

8. How much does it typically cost to repair the Throttle/Pedal Position Sensor/Switch 'D' Circuit High issue in a Mercedes-Benz?

- The cost of repairing the P2123 code can vary depending on the specific cause of the issue, but it may range from a few hundred to over a thousand dollars, including parts and labor.

9. Are there any DIY methods to troubleshoot or repair the P2123 code in a Mercedes-Benz?

- While some basic inspections and cleaning procedures can be done by DIY enthusiasts, diagnosing and repairing the P2123 code may require specialized tools and expertise, so it is recommended to consult a professional mechanic.

10. How can I prevent the recurrence of the P2123 code in my Mercedes-Benz in the future?

- To prevent the P2123 code from reoccurring, it is important to perform regular maintenance on the throttle and pedal position sensors, keep the wiring connections secure, and address any issues promptly to avoid further complications.

1. What are the common symptoms of OBDII code P2123 in a Mercedes-Benz related to the Throttle/Pedal Position Sensor/Switch 'D' Circuit High?

- Common symptoms include reduced engine power, hesitation or stalling when accelerating, and the vehicle going into limp mode.

2. What are the possible causes of OBDII code P2123 in a Mercedes-Benz?

- The code P2123 can be triggered by a faulty throttle position sensor, damaged wiring or connectors, or issues with the throttle pedal position sensor/switch.

3. How can I diagnose the cause of OBDII code P2123 in my Mercedes-Benz?

- Diagnosing the code involves inspecting the wiring and connectors for damage, testing the throttle position sensor's functionality, and checking the throttle pedal position sensor/switch.

4. Can I drive my Mercedes-Benz with OBDII code P2123 present?

- It is not recommended to drive your vehicle with code P2123 present as it can lead to performance issues and potential safety hazards. It's best to have the issue diagnosed and repaired promptly.

5. What are the repair options for OBDII code P2123 in a Mercedes-Benz?

- Repair options may include replacing the throttle position sensor, repairing damaged wiring or connectors, or addressing any issues with the throttle pedal position sensor/switch.

6. Is it possible to reset OBDII code P2123 in a Mercedes-Benz without fixing the underlying issue?

- While you can clear the code with an OBDII scanner, it will likely reappear if the underlying issue is not addressed. It's important to diagnose and fix the root cause of the problem.

7. How long does it typically take to repair OBDII code P2123 in a Mercedes-Benz?

- The repair time can vary depending on the specific cause of the code and the extent of the repairs needed. It's best to consult a mechanic for a more accurate estimate.

8. Are there any preventive measures I can take to avoid OBDII code P2123 in my Mercedes-Benz?

- Regular maintenance, such as checking and cleaning throttle components, inspecting wiring for damage, and addressing any warning signs early on, can help prevent code P2123 from occurring.

9. Can a DIY enthusiast fix OBDII code P2123 in a Mercedes-Benz?

- Depending on your skill level and access to tools, DIY enthusiasts may be able to address simpler causes like checking and cleaning connectors or replacing the throttle position sensor. However, more complex issues may require professional assistance.

10. Will OBDII code P2123 cause permanent damage to my Mercedes-Benz if not repaired promptly?

- Ignoring OBDII code P2123 can potentially lead to further engine performance issues and damage over time. It is advisable to address the problem promptly to prevent any long-term damage.

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