Everything you need to know about the accelerator pedal sensor: Structure, typical faults and workshop tips

Accelerator pedal sensor

10037926a_AM0_white_inclined

The accelerator pedal sensor transmits the position of the accelerator pedal to the engine control unit. Based on this information, the load requested by the driver can be implemented immediately. On this page we will explain the principle according to which modern pedal travel transmitters operate, and which symptoms indicate a fault in this sensor. You will also find out how accelerator pedal sensors are checked in the workshop.

The following technical information and practical tips have been compiled by HELLA in order to provide professional support to vehicle workshops in their day-to-day work. The information provided on this website is intended for suitably qualified personnel only.

How the accelerator pedal sensor works

Accelerator pedal sensor (pedal value transmitter)

Design of accelerator pedal sensor (pedal value transmitter)

Modern vehicles are being equipped with an ever-increasing number of electronic components. Among other things, this is due to legal regulations, e.g. those governing a reduction in emissions and fuel consumption. Electronic components are also increasingly being used to increase active and passive safety as well as driving comfort. One of the most important components is the accelerator pedal sensor.

When it comes to automotive applications, a non-contact sensor based on an inductive principle is increasingly being used. This sensor comprises a stator (which includes an excitation coil, receiver coils, and an electronic evaluation unit) and a rotor (formed of one or more closed conductive loops with a certain geometry).

The application of alternating voltage to the transmission coil produces a magnetic field which induces voltages in the receiver coils. A current is also induced in the rotor conductive loops which, in turn, influences the magnetic field of the receiver coils. Voltage amplitudes are produced depending on the position of the rotor relative to the receiver coils in the stator. These are processed in an electronic evaluation unit and then transmitted to the control unit in the form of direct-current voltage. This evaluates the signal and forwards on the relevant pulse, e.g. to the throttle valve actuator. The characteristics of the voltage signal depend on how the accelerator pedal has been pressed.

Checking the accelerator pedal sensor

The following test steps should be considered during troubleshooting:

Read out fault code
Visual inspection of the accelerator pedal sensor to check for mechanical damage
Visual inspection of the relevant electrical connections and cables to ensure they are properly fitted and for any damage
Check of the sensor using an oscilloscope and multimeter

Using the example of a MB A-Class (150) 1.7, the following test steps, technical data, and figures are listed to explain the troubleshooting work.

Control unit pin	Signal	Test conditions	Reference value
C5 blue-yellow	→	Acceleration off	0 V
C5	→	Acceleration off	4,5 – 5,5 V
C8 violet-yellow	⊥	Acceleration on	0 V
C blue-grey	←	Acceleration on, accelerator pedal released	0,15 V
C9	←	Acceleration on, accelerator pedal pressed	2,3 V
C10 violet-green	←	Acceleration on, accelerator pedal released	0,23 V
C10	←	Acceleration on, accelerator pedal pressed	4,66 V
C23 brown-white	⊥	Acceleration on	0 V

→ output signal ← input signal ⊥ control unit ground

Checking the accelerator pedal sensor: Signal recording from pin C5 — Signal recording from pin C5

SIGNAL RECORDING FROM PIN C5

This measurement checks the voltage supply to the sensor. Ignition on/off.

Checking the accelerator pedal sensor: Signal recording from pin C9 — Signal recording from pin C9

SIGNAL RECORDING FROM PIN C9

Ignition on, press pedal, then release pedal. The signal rises and falls depending on the speed at which the pedal is pressed and released

Checking the accelerator pedal sensor: Signal recording from pin C10 — Signal recording from pin C10

SIGNAL RECORDING FROM PIN C10

Ignition on, press pedal, then release pedal. The signal rises and falls depending on the speed at which the pedal is pressed and released.

The measurements should be performed by two people. The work involved in capturing the signals on the sensor, carrying out various test cycles, and performing diagnostics work on the oscilloscope is difficult for a single person to handle, and it will take them much longer to complete this work.

Accelerator Pedal Training

In this video, we will show you the technologies of the accelerator pedals, how they work and discuss the faults. In addition, we will show the diagnosis of the element? using mega macs and tell you what to look for.

Diagnostics, Measurement & Tools

Identify faults precisely with professional multi-brand workshop equipment and guided functions. Get quick solutions using specialized diagnostic devices, technical data and optional AI support — the foundation for first-time fixes.

Adjustment

Carry out precise adjustments and system settings after repairs to avoid comebacks. Backed by accurate diagnostic workflows and step-by-step guided procedures to make complex jobs easier.

Spare Parts

Benefit from OE quality components designed to match diagnostic results exactly. Supported by professional data management for easy and correct parts identification, ensuring you fit the right part the first time.

Calibration

Restore vehicle systems to OEM specifications and secure emissions & safety compliance. Supported by HELLA’s technical info and calibration workflows, ensuring smooth vehicle handover and fewer issues down the line.

Support & Hotline

Access fast expert help when needed. HELLA’s technical hotline handles over 500,000 calls per year, giving you direct access to specialists with years of practical workshop experience.

HELLA Tech-/Partner World

Get access to technical information, documentation and support around the clock. HELLA TECH WORLD receives over 5 million visits per year, providing trusted repair instructions, diagnostics tips and product data.

Remote Services

Bring expert knowledge directly into your workshop without outsourcing. Use real-time remote assistance for coding, calibration and advanced procedures — keeping high-value jobs in-house.

Training

Keep your team up to date with the latest technologies, diagnostics methods and repair procedures. HELLA offers ongoing training to strengthen workshop know-how and ensure professional results on modern vehicles.

HELLA GUTMANN Diagnostics that fit perfectly

macsRemote Services

Not helpful at all

5

4

3

2

1

Very helpful

Spare Parts Finder

Licence Plate Manual vehicle identification OE-No.

Spare Parts Finder

Simple vehicle identification with licence plate number Also determine spare parts with OE numbers Detailed product information Find wholesalers near you

You might also be interested in

Basic Knowledge

Electric hatchback actuator: troubleshooting

Find out how to systematically diagnose and specifically narrow down common faults in the electric hatchback actuator.

Reading Time: 8 minutes

Basic Knowledge

Checking the exhaust gas temperature sensor

Step-by-step instructions for testing the exhaust gas temperature sensor - shown on the VW Passat 2.0 TDI.

Reading Time: 3 minutes

Basic Knowledge

Idle speed controller & actuator - function & check

Everything you need to know about testing and troubleshooting idle speed regulators: function, typical symptoms and repair tips for your workshop.

Reading Time: 3 minutes

Basic Knowledge

Maintenance and diagnostics of 77 GHz radar sensors

Find out how the HELLA 77 GHz radar sensor supports driver assistance systems and accurately identifies objects in any weather conditions. Discover the design, function and applications in the vehicle.

Reading Time: 7 minutes

Basic Knowledge

Injection nozzle/injection valve – Function & checks

Find out how to diagnose a defective fuel injector and replace it in the workshop.

Reading Time: 6 minutes

Basic Knowledge

Throttle valve switch – function & troubleshooting

Everything you need to know to diagnose and repair the throttle valve switch - helpful workshop tips.

Reading Time: 2 minutes

Basic Knowledge

TPS sensor – function & troubleshooting

Learn how to check a throttle potentiometer for defects and recognize the most common symptoms.

Reading Time: 2 minutes

Basic Knowledge

Camshaft position sensor - function & troubleshooting

Learn all about the function and testing of the camshaft sensor and possible symptoms of a defect.

Reading Time: 2 minutes

Basic Knowledge

Air-mass sensor - Function & troubleshooting

Learn how to check a mass air flow sensor, detect defective sensors and replace them professionally.

Reading Time: 2 minutes

Basic Knowledge

Check and change ABS and wheel speed sensors

Instructions for diagnosing and replacing the ABS sensor - all the steps for a professional repair.

Reading Time: 10 minutes