P2138 Lexus Code - Throttle Pedal Position Sensor/Switch 'D' / 'E' Voltage Correlation
Quick Answer
The Accelerator Pedal Position (APP) sensor is built into the accelerator pedal sensor assembly and has 2 sensor circuits: VPA (main) and VPA2 (sub). Common causes include Faulty Accelerator Pedal Position (APP) 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 Lexus indicates Throttle Pedal Position Sensor/Switch 'D' / 'E' Voltage Correlation.
- Common causes
- Common causes include Faulty Accelerator Pedal Position (APP) 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.
Code P2138 Lexus Description
The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA and VPA2 and controls the throttle actuator according to these signals.
When either the output voltage of VPA or VPA2 deviates from the standard range, or the difference between the output voltages of the 2 sensor circuits is more than the threshold, the ECM determines that there is a malfunction in the accelerator pedal position sensor. The ECM then illuminates the MIL and stores a Diagnostic Trouble Code (DTC).
What are the Possible Causes of the DTC P2138 Lexus?
- Faulty Accelerator Pedal Position (APP) Sensor
- Accelerator Pedal Position Sensor harness is open or shorted
- Accelerator Pedal Position Sensor circuit poor electrical connection
- Faulty Engine Control Module (ECM)
How to Fix the DTC P2138 Lexus?
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 Lexus 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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Frequently Asked Questions about P2138 Lexus Code
1. What does the OBDII code P2138 mean on a Lexus?
P2138 indicates a voltage correlation issue between the Throttle Pedal Position Sensor/Switch 'D' and 'E', suggesting a potential problem with the accelerator pedal assembly or related wiring.
2. What are the common symptoms of code P2138 in a Lexus?
Common symptoms include reduced engine power, the vehicle going into "limp mode," delayed throttle response, or the illumination of the Check Engine Light.
3. What causes the P2138 code to appear on a Lexus?
The code is usually caused by a faulty throttle pedal position sensor, damaged or corroded wiring, poor connections, or a malfunction in the engine control module (ECM).
4. Can I drive my Lexus with the P2138 code?
It’s not recommended to drive with this code, as it may cause unpredictable throttle behavior or limit engine power, which can be unsafe in certain situations.
5. How can I fix the P2138 code on my Lexus?
Start by inspecting and cleaning the throttle pedal sensor connectors and wiring. If the issue persists, the throttle pedal assembly may need to be replaced or the ECM inspected.
6. How much does it cost to repair the P2138 code on a Lexus?
Repairs may cost between $100 and $300 for parts and labor, depending on whether the throttle pedal assembly or wiring needs replacement.
7. Can a dirty throttle body cause the P2138 code?
While a dirty throttle body can cause other throttle-related issues, it typically does not trigger the P2138 code, which is related to the pedal sensor.
8. What tools are needed to diagnose the P2138 code on a Lexus?
You’ll need an OBDII scanner, a multimeter to test voltage, and possibly wiring diagrams to inspect the sensor and connections.
9. Does the P2138 code always mean the throttle pedal sensor is bad?
No, the issue could also stem from wiring problems, corroded connectors, or a fault in the ECM.
10. How can I prevent the P2138 code from reoccurring on my Lexus?
Regularly inspect and clean the throttle pedal sensor connectors, avoid water exposure to the wiring, and ensure repairs are performed using quality parts.
Discuss the causes and fixes for P2138 Lexus OBDII Code
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