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P2138 Fault Code

You can find information about the P2138 fault code on this page.

It is one of the most popular fault codes that people search for on this website (in the top 50).

We have given it a seriousness of 9/10 with 1 being the least serious and 10 being the worst.

P2138 Short Description

"Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation"

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Description Icon Long Description

Fault code P2138 is logged when the engine control unit (ECU) has detected an error with the signals from the accelerator pedal and the throttle position. This happens when the voltage signals of the two components do not correlate with one another.

These two signals allow the ECU to know what position the throttle is in, allowing optimizations for air-fuel mixture and various other features of an engine that is functioning properly.

The throttle system controls the amount of air-fuel mixture that is in the engine at any given time. By depressing or releasing the accelerator pedal in conjunction with the throttle system, the vehicle is able to accelerate or decelerate.

This fault code means that the ECU is essentially guessing various parameters that it would otherwise not have to.

This issue is relatively uncommon, but manufacturers like Honda, Volkswagen, and Toyota are among the most searched when it comes to this fault code.

Warnings Icon Other Signs of This Problem

The signs of fault code P2138 should be relatively noticeable as the vehicle will not behave normally in terms of acceleration.

The most notable sign will be the Check Engine light being illuminated on the dashboard.

Other signs can be that the vehicle will run very poorly. This can come in the form of idling issues and poor acceleration.

Look out for additional codes regarding the idling of the vehicle. If the throttle is in the incorrect position at idle, it can result in a high or low idle. These could help detect the issue. Codes like P0505, P0506, and P0507 could all be present.

The vehicle may not even start at all in some instances.

Broken Down Icon What Could Be The Problem?

There are various causes that could be the source of the issue. These can be found in either the throttle system or the pedal side.

Either the throttle position sensor or the accelerator pedal position sensor could be faulty, providing incorrect values. This could lead to two signals that do not correlate.

Additionally, the wiring for either sensor could have faults like frayed or damaged wires or bad connections.

In terms of the throttle system, the throttle body could be damaged or faulty. In the case of an electronic throttle system, the throttle body motor could also be suffering a malfunction.

In somewhat rare instances, the ECU itself could be faulty.

Fixed Icon Fixes

Fixes for P2138 are heavily reliant on replacing damaged or faulty parts.

If either the throttle position sensor or the accelerator pedal position sensor is faulty, they need to be replaced respectively.

Additionally, the connections and wires to these sensors should be checked for damage. If there is damage, fraying, or loose connections, these should be fixed. The wiring for the throttle body motor should also be checked.

A defective throttle body should also be replaced if necessary.

If there is an issue with the ECU, it should be replaced. Additionally, the ECU may require a software update.

Danger Icon Seriousness

Fault code P2138 should be considered a severe issue.

Incorrect operation of the throttle can be very dangerous to both the vehicle and its occupants. Additionally, there can be damage to the engine and its components from the ECU not having the required information.

This problem should be resolved immediately.

P2138 Image

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