P2138 Technical Description
Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation
If you’re seeing the P2138 trouble code, this guide will help you understand what it means, the symptoms to look out for, its causes, and how to fix it.
I’ve dealt with the P2138 code before, so you’re in good hands.
You’ll learn why the P2138 code appears, common symptoms like throttle response issues, and practical fixes to get your car running smoothly again.
Let’s get into it!
Key Takeaways
- P2138 trouble code relates to a mismatch between TPS and APPS signals.
- Common symptoms include reduced throttle response and limp mode.
- Causes can be faulty sensors, damaged wiring, or ECM issues.
- Diagnose by checking for other codes, inspecting wiring, and testing sensors.
- Fixes include replacing faulty sensors, repairing wiring, and clearing codes.
- If issues persist, consulting a professional mechanic may be necessary.
Table of ContentsShow
What Does P2138 Trouble Code Mean?
The P2138 trouble code signals an issue with the correlation between the voltages from the throttle position sensor (TPS) and the accelerator pedal position sensor (APPS).
Both sensors are vital for your car’s drive-by-wire system. This system controls the throttle opening, which in turn regulates the engine’s power output based on the pedal position.
When you press the accelerator pedal, the APPS sends a signal to the engine control module (ECM).
The ECM then uses this signal to determine the desired throttle position and relays it to the TPS. The TPS measures the actual position of the throttle and sends this data back to the ECM.
If there’s a discrepancy between the signals from the TPS and APPS, the ECM triggers the P2138 code.
In simpler terms, the P2138 code means your car’s computer has detected that the signals from the accelerator pedal and the throttle body don’t match up as expected.
This mismatch can cause the car to go into “limp mode,” where performance is reduced to prevent damage.
This issue often leads to symptoms like poor throttle response, a lack of power, or even a complete inability to accelerate.
The car might feel sluggish or unresponsive. These symptoms can be particularly dangerous if they occur while driving, as they can impact your ability to control the vehicle.
The P2138 code can stem from several causes, including faulty sensors, damaged wiring, or issues with the ECM.
Identifying and addressing the exact cause is crucial to restoring normal function to your vehicle’s throttle system.
P2138 Trouble Code Symptoms
Experiencing the P2138 trouble code often comes with noticeable symptoms that can impact your driving. Here are the key signs to look out for:
- Reduced throttle response
- Sluggish acceleration
- Inconsistent engine power
- Check Engine Light illuminated
- Car going into “limp mode”
- Hesitation or stalling while driving
P2138 Trouble Code Causes
Several factors can trigger the P2138 trouble code. Here are the common causes:
- Faulty throttle position sensor (TPS)
- Faulty accelerator pedal position sensor (APPS)
- Damaged or frayed wiring
- Loose or corroded electrical connections
- Issues with the engine control module (ECM)
How To Fix A P2138 Trouble Code
To fix a P2138 trouble code, follow these steps to diagnose and repair the issue:
1. Check for other codes
Use an OBD-II scanner to see if there are any other related codes. Multiple codes can help pinpoint the problem.
2. Inspect wiring and connections
Look for any visible damage to the wiring connected to the TPS and APPS. Check for frayed wires, loose connectors, or corrosion.
3. Test the sensors
Throttle Position Sensor (TPS): Use a multimeter to measure the voltage from the TPS. The voltage should change smoothly as you move the throttle. If it’s erratic or doesn’t change, the TPS might be faulty.
Accelerator Pedal Position Sensor (APPS): Similarly, test the APPS. Press the accelerator pedal and check if the voltage changes smoothly. Inconsistent readings suggest a faulty APPS.
4. Replace faulty sensors
If you find a faulty TPS or APPS, replace the sensor. Ensure you buy a quality replacement that matches your vehicle’s specifications.
5. Repair or replace damaged wiring
If you find damaged wiring, repair or replace it as needed. Ensure all connections are secure and free from corrosion.
6. Clear the codes
After repairs, use your OBD-II scanner to clear the trouble codes. This resets the system and allows you to see if the problem is resolved.
7. Test drive
Take your car for a test drive to ensure the issue is fixed. Monitor the performance and check if the Check Engine Light stays off.
If the P2138 code returns, it may indicate a deeper issue with the ECM or further wiring problems. In such cases, consulting a professional mechanic is advisable.
Conclusion
Now you know what the P2138 trouble code means and how to fix it.
Got any other weird car issues popping up?
Drop a comment below about the strangest car problem you’ve ever faced. Let’s hear your stories!
