SureTrack Real Fix: Pedal Diagnostics

Real Fixes from the SureTrackĀ® expert information resource are documented issues from actual shop repair orders and community discussions. Read on to see how SureTrack can help you correct issues that are not easily diagnosed using OEM information alone. SureTrack is currently available free with the purchase of a current Snap-onĀ® diagnostic software version.

When a check engine light comes on and a code P2127 appears, it’s time to start the process of elimination using more diagnostic tests. Diagnosing this type of fault is made so much easier with Triton or the Zeus as the live data can be used to monitor the accelerator pedal position. The Scope enables you to check powers and grounds via the digital multi meter and the Lab scope shows a visual of the faulty accelerator pedal position sensor.

2012 Mercedes-Benz Sprinter 2.1L Diesel

P2127, Replaced Accelerator Pedal

The customer states the check engine light is on.

Connected a scan tool and found code P2127 – Throttle/Pedal Position Sensor/Switch “E” Circuit Low. Used the scan tool to monitor live data, performed a throttle sweep and observed the accelerator pedal position sensor parameter did not maintain the specified correlation as the throttle was swept. Visually inspected the accelerator pedal position sensor wiring harness and found no obvious signs of damage. Used a multi-meter to check for the presence of voltage and ground at the accelerator pedal position sensor and found both were present. Backprobed the accelerator pedal position sensor, monitored the sensor signal on a lab scope and found the accelerator pedal position sensor signals observed on the lab scope intermittently dropped out as the throttle was swept. These test results verified the accelerator pedal position sensor was faulty. The accelerator pedal position sensor is integrated into the accelerator pedal and is replaced as an entire unit.

Replaced the accelerator pedal, cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.

SureTrackĀ® is a powerful value-added feature available with select Snap-on diagnostics tools. It offers an exclusive combination of expert knowledge and detailed parts replacement records, all wrapped in an interactive community.

Want more? Click here for more information on using SureTrack.

Looking for diagnostic tools? Click here to request more information on Snap-on diagnostic tools.

New or Expired SureTrack users: Click here for authorization key instructions.

About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.