P2138: Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation
What Does P2138 Mean?
P2138 is a diagnostic trouble code indicating: Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation. This code relates to the powertrain system. It has been reported in NHTSA complaints across 26 different vehicle models.
Symptoms of P2138
- ⚠️ Check engine light illuminated
- ⚠️ Hesitation during acceleration
- ⚠️ Poor fuel economy
- ⚠️ Loss of engine power
- ⚠️ Vehicle won't start
- ⚠️ Jerking or surging while driving
Common Causes
- 🔍 Faulty oxygen sensor
- 🔍 Throttle body or throttle position sensor issue
- 🔍 Wiring or connector problem
- 🔍 Loose or damaged gas cap
- 🔍 Sensor or control module malfunction
P2138 Reports by Year
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"The way the accelerator pedal sensor is positioned allows for water infiltration from wet carpet / tracked in snow and water. The component is available for inspection upon request. Once sufficiently saturated the sensor fails, and ceases function DURING VEHICLE MOVEMENT. The problem is reproducible"
— Toyota Prius owner, 02/10/2026
"The contact owns a 2016 Honda Accord. The contact stated that while driving approximately 55-60 MPH, the check engine, power steering, traction control, and TPMS warning lights were illuminated. The vehicle lost power, but the driver was able to pull over safely. The contact stated that the gear shi"
— Honda Accord owner, 01/01/2023
"In June 2016, my Honda CR-V 2015 broke down, lost all power, and stopped working in the middle of the road. The vehicle was towed to a Honda Dealership - Diamond Bar, CA. The Honda Mechanic diagnosed a P2138, did not solve the problem, and sent me home. The vehicle broke down once again, only for th"
— Honda Cr-V owner, 08/13/2021
Source: NHTSA Complaints Database
Most Reported Vehicles for P2138
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | SUBARU OUTBACK | |
| 2 | CHEVROLET MALIBU | |
| 3 | CHEVROLET IMPALA | |
| 4 | SUBARU LEGACY | |
| 5 | CHEVROLET TRAVERSE | |
| 6 | SUBARU FORESTER | |
| 7 | CHEVROLET EQUINOX | |
| 8 | CHEVROLET TAHOE | |
| 9 | CHEVROLET CAMARO | |
| 10 | GMC ACADIA | |
| 11 | CHEVROLET SILVERADO | |
| 12 | CHEVROLET COLORADO | |
| 13 | NISSAN VERSA | |
| 14 | KIA SORENTO | |
| 15 | SUBARU IMPREZA |
P2138 Reports by Vehicle
Detailed NHTSA complaint analysis for each vehicle model.
Diagnostic Tips
- Scan all modules, save freeze-frame data, and clear unrelated history codes before focusing on P2138.
- Confirm whether companion codes are present first; they often identify the root cause sooner than the headline DTC.
- Prioritize inspection around vehicle speed control and the most common failure path for this code family.
- Check APP/TPS correlation PIDs through slow pedal sweeps; look for dropouts, lag, or disagreement between paired sensors.
- After each repair step, complete one drive cycle and verify readiness monitors instead of judging success after a quick idle test.
- If the code keeps returning on high-incidence platforms (for example SUBARU OUTBACK), check TSB patterns and wiring/connector fitment before major part replacement.
Common Mistakes to Avoid
- ❌ Skipping freeze-frame review and losing the exact RPM/load conditions when the fault set.
- ❌ Replacing the throttle body without checking APP sensor correlation and connector pin tension.
- ❌ Clearing P2138 and returning the car before monitors complete — this often creates repeat visits.
- ❌ Treating intermittent wiring or connector faults as permanent component failure without wiggle testing.
Frequently Asked Questions
Can I drive with this code?
Will this code clear itself?
How do I find the exact cause?
What To Do Next
Possible Fixes
- 🔧 Have the code scanned with a professional-grade scanner to read freeze frame data
- 🔧 Check and tighten the gas cap — replace if cracked or damaged ($5-15)
- 🔧 Test the relevant sensor(s) with a multimeter before replacing
- 🔧 Inspect wiring harness and connectors for damage, corrosion, or loose connections
- 🔧 If DIY repair isn't feasible, get a diagnostic from a trusted mechanic ($50-150)
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.