AutoCodes – Lincoln – P2138 Lincoln

P2138 Lincoln Code - Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation

Quick Answer

The Accelerator Pedal Position (APP) sensor is an input to the Powertrain Control Module (PCM) and used to determine the amount of torque requested by the operator. Common causes include Faulty Accelerator Pedal Position (APP) Sensor, Accelerator Pedal Position (APP) Sensor harness is open or shorted, Accelerator Pedal Position (APP) 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: P2138 Lincoln indicates Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation.
Common causes: Common causes include Faulty Accelerator Pedal Position (APP) Sensor, Accelerator Pedal Position (APP) Sensor harness is open or shorted, Accelerator Pedal Position (APP) 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.

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Code Popularity 2,486

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

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Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
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Code P2138 Lincoln Description

The Accelerator Pedal Position (APP) sensor is an input to the Powertrain Control Module (PCM) and used to determine the amount of torque requested by the operator. There are 2 pedal position signals in the sensor. Both signals, APP and APP2, have a positive slope (increasing angle, increasing voltage), but are offset and increase at different rates. The 2 pedal position signals make sure the PCM receives a correct input even if 1 signal has a concern. The PCM determines if a signal is incorrect by calculating where it should be, inferred from the other signals. If a concern is present with one of the circuits the other input is used. There are 2 reference voltage circuits, 2 signal return circuits, and 2 signal circuits (a total of 6 circuits and pins) between the PCM and the APP sensor assembly. The pedal position signal is converted to pedal travel degrees (rotary angle) by the PCM. The software converts these degrees to counts, which is the input to the torque based strategy. If the APP sensor inputs APP1 and APP2 disagree on the position of the accelerator pedal by more than an expected value, the P2138 is set.

OBDII Code P2138 Lincoln - Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation - AutoCodes.com — P2138 Lincoln Code - Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation

What does this mean?

What are the Possible Causes of the DTC P2138 Lincoln?

Faulty Accelerator Pedal Position (APP) Sensor
Accelerator Pedal Position (APP) Sensor harness is open or shorted
Accelerator Pedal Position (APP) Sensor circuit poor electrical connection
Faulty Powertrain Control Module (PCM)

How to Fix the DTC P2138 Lincoln?

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 P2138 Lincoln 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.

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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 P2138 Lincoln Code

What does the OBD-II code P2138 mean on a Lincoln?

P2138 indicates a voltage correlation issue between the throttle/pedal position sensors 'D' and 'E', which monitor the accelerator pedal's movement.

What symptoms are associated with code P2138 in a Lincoln?

Common symptoms include reduced engine power, hesitation during acceleration, the vehicle entering "limp mode," and the check engine light illuminating.

What causes the P2138 code in a Lincoln?

The code is typically caused by a faulty accelerator pedal position sensor, damaged wiring or connectors, or issues with the throttle body.

Can I still drive my Lincoln with a P2138 code?

Driving with this code is not recommended as it can lead to unsafe driving conditions due to reduced engine power and unpredictable throttle response.

How do I diagnose the P2138 code on my Lincoln?

Start by inspecting the accelerator pedal sensor, wiring, and connectors for damage. Use a multimeter or scan tool to check voltage readings from sensors 'D' and 'E'.

How do I fix the P2138 code on a Lincoln?

Repairs may include replacing the accelerator pedal position sensor, repairing damaged wiring or connectors, or addressing issues with the throttle body.

Is the P2138 code specific to Lincoln vehicles?

No, P2138 is a generic OBD-II code that applies to many vehicles, but the specific diagnosis and repair steps can vary by make and model.

What tools are needed to diagnose and repair the P2138 code in a Lincoln?

You’ll typically need a scan tool, multimeter, and possibly basic hand tools for inspecting and replacing components.

How much does it cost to fix the P2138 code in a Lincoln?

Repair costs can vary widely, but replacing an accelerator pedal position sensor typically costs between $100 and $300, plus labor.

Can a dirty throttle body cause the P2138 code on a Lincoln?

While a dirty throttle body isn't the most common cause, it can sometimes lead to voltage irregularities that trigger the code. Cleaning the throttle body may help.