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P2138 on SUBARU LEGACY

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

NHTSA Reports
17
Severity
Medium
Most Affected
2006, 2005
Crashes / Fires
0 / 0
Source: NHTSA Complaints Database · SAE J2012

What P2138 Means on Your SUBARU LEGACY

P2138 is a diagnostic trouble code indicating: Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation. This code relates to the powertrain system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

17 SUBARU LEGACY owners have reported this issue to NHTSA across model years 2005-2006. Most reports come from the 2006, 2005 model years. The most commonly reported component is Vehicle Speed Control (41.2% of reports).

Real SUBARU LEGACY Owner Reports

Source: NHTSA Complaints Database

"Driving southbound on hwy 17 at 60mph 11/15/2020 engine suddenly went to idle. throttle became unresponsive. check engine light illuminated. i drifted to safety off the highway. engine still idling, throttle unresponsive."

— 2005 SUBARU LEGACY owner · VEHICLE SPEED CONTROL · Filed 11/15/2020

"While pressing the accelerator there was no response. the car continued at it's normal idle, but pressing on the gas gave no response. i was able to coast to a stop off the road and turn the car off and back on, which fixed the problem the first time."

— 2005 SUBARU LEGACY owner · VEHICLE SPEED CONTROL,FUEL/PROPULSION SYSTEM · Filed 04/16/2015

"I was driving on the highway, and the car seem to loose power, luckily i noticed it, as i was able to cost over to the side of the rode. i own a carmd, and attached it to my car, it gave me code p2138 which means the throttle position sensors (2 of them) not being in agreement."

— 2005 SUBARU LEGACY owner · ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL,FUEL/PROPULSION SYSTEM · Filed 12/22/2012

"For the second time my check engine light has come on and my car has gone into a fail safe mode while driving (eliminating the ability to accelerate). the code the computer provides is p2138, which refers to the throttle position sensors (there are two) not being in agreement."

— 2005 SUBARU LEGACY owner · POWER TRAIN,ELECTRICAL SYSTEM,FUEL/PROPULSION SYSTEM · Filed 12/18/2012

"Car has been very slow to reduce rpms when shifting gears or when stopped (and in neutral) for the past few weeks. today, when pulling into a starbucks, the car surged forward. luckily i have a stick shift and just pushed the clutch in. after surging, the check engine light came on."

— 2005 SUBARU LEGACY owner · ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL,ENGINE · Filed 10/14/2012

All reports filed by vehicle owners directly with the U.S. Department of Transportation.

📊 Complaint Trend by Model Year

5
'05
12
'06

Common Causes on SUBARU LEGACY

Based on NHTSA complaint component analysis for this vehicle.

VEHICLE SPEED CONTROL 41.2%
ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL,FUEL/PROPULSION SYSTEM 11.8%
VEHICLE SPEED CONTROL,FUEL/PROPULSION SYSTEM 5.9%
POWER TRAIN,ELECTRICAL SYSTEM,FUEL/PROPULSION SYSTEM 5.9%
ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL,ENGINE 5.9%

What To Do Next

  1. 1
    Check for recalls on YOUR VIN

    Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.

  2. 2
    Get a proper diagnosis

    A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.

  3. 3
    Compare repair quotes

    Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.

Frequently Asked Questions

What does P2138 mean on a SUBARU LEGACY?
P2138 indicates: Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation. This is a powertrain code. 17 SUBARU LEGACY owners have reported this to NHTSA.
What are the most common causes of P2138 on SUBARU LEGACY?
Based on 17 NHTSA reports, the most commonly cited components are: Vehicle Speed Control, Electrical System,Vehicle Speed Control,Fuel/Propulsion System, Vehicle Speed Control,Fuel/Propulsion System. These percentages are based on the component field in owner complaints.
Is P2138 serious on my SUBARU LEGACY?
Of 17 NHTSA reports for this code on SUBARU LEGACY, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.
What should I do if my SUBARU LEGACY shows P2138?
1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare.

P2138 on Other Vehicles