AutoCodes – Saturn – P2138 Saturn

P2138 Saturn Code - Accelerator Pedal Position Sensor 1-2 Correlation

Quick Answer

The Accelerator Pedal Position (APP) sensor is made up of 2 sensors that are housed inside one assembly. 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: P2138 Saturn indicates Accelerator Pedal Position Sensor 1-2 Correlation.
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.

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Code Popularity 28,541

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

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
Comments
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Code P2138 Saturn Description

The Accelerator Pedal Position (APP) sensor is made up of 2 sensors that are housed inside one assembly. The Engine Control Module (ECM) supplies a separate 5-volt reference circuit and a low reference circuit for each of the sensors. The 5-volt reference for APP sensor 1 is supplied from the same source in the ECM as the 5-volt reference for the mass air flow (MAF) sensor and the fuel tank pressure (FTP) sensor. The 5-volt reference voltage for all of the sensors is supplied on separate ECM terminals, but the terminals are connected internally to a voltage supply. The APP sensor 1 sends a signal from the sensor to the ECM indicating the accelerator pedal position. The ECM actuates the throttle plates based on this information. If the ECM detects that the APP sensors are not within a predicted value from each other, DTC P2138 sets.

OBDII Code P2138 Saturn - Accelerator Pedal Position Sensor 1-2 Correlation - AutoCodes.com — P2138 Saturn Code - Accelerator Pedal Position Sensor 1-2 Correlation

What does this mean?

What are the Possible Causes of the DTC P2138 Saturn?

Faulty Accelerator Pedal Position Sensor
Accelerator Pedal Position Sensor harness is open or shorted
Accelerator Pedal Position Sensor circuit poor electrical connection
Faulty Electric Throttle Control Actuator

How to Fix the DTC P2138 Saturn?

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 Saturn 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 P2138 Saturn code?

Need more information on how to fix the P2138 Saturn code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P2138 Saturn code diagnosed by a professional: Find a repair shop in your area

Information for Specific Saturn Models

P2138 2005 Saturn Ion — Accelerator Pedal Position Sensor 1-2 Correlation

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 Saturn Code

What does OBDII code P2138 mean on a Saturn?

P2138 indicates an issue with the Accelerator Pedal Position Sensor (APP) 1-2 correlation, meaning the two sensors in the pedal assembly are reporting inconsistent signals to the engine control module (ECM).

What are the symptoms of code P2138 in a Saturn vehicle?

Common symptoms include reduced engine power (limp mode), hesitation or lack of acceleration, the check engine light illuminating, and potentially a throttle response delay.

What causes the P2138 code to appear on a Saturn?

The most common causes are a faulty accelerator pedal position sensor, damaged or corroded wiring/connectors, or issues with the ECM/PCM interpreting the signals from the sensors.

Can I drive my Saturn with a P2138 code?

Driving with a P2138 code is not recommended, as the vehicle may enter limp mode or experience unpredictable throttle response, which can be unsafe.

How do you fix a P2138 code on a Saturn?

Fixes may include replacing the accelerator pedal assembly, repairing or replacing damaged wiring/connectors, or reprogramming/updating the ECM if necessary.

How do I diagnose the P2138 code on my Saturn?

Start by checking the wiring and connectors around the accelerator pedal for damage or corrosion. Use a scan tool to monitor sensor readings and verify if the APP sensors are giving inconsistent signals.

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

While a dirty throttle body can cause acceleration issues, it is not a direct cause of the P2138 code, which specifically relates to APP sensor signal inconsistencies.

How much does it cost to fix a P2138 code on a Saturn?

Repair costs can vary but typically range from $150 to $300 for parts and labor, depending on whether the pedal assembly or wiring requires replacement.

Is a software update required to fix the P2138 code on a Saturn?

In some cases, a software update or reprogramming of the ECM/PCM may be necessary, especially if the issue persists after replacing hardware components.

What tools are needed to troubleshoot the P2138 code?

Basic tools include a scan tool or OBDII reader with live data capability, a multimeter to check wiring and voltage, and possibly a repair manual for wiring diagrams specific to your Saturn model.