The Lemon IndexThe two gas pedal position signals disagree, so the car may go into reduced power or not respond to the pedal. Full P2138 page
18 owner complaints · the #1 code Subaru Legacy owners name · 56% of Subaru Legacy complaints that name a code (every car: 1.7%)
Middle of 94,000 miles · most between 64,000 and 138,000 (18 owners gave it)
Subaru Legacy owners named P2138 in 18 complaints to the U.S. government (NHTSA), most often on the 2006, 2005 and 2004 model years, at a middle of 94,000 miles. The part they name most is the throttle body (2 complaints). Complaints are owner reports, not proof of a defect.
Subaru Legacy model years that report P2138
- 200612
- 20055
- 20041
Owner complaints naming P2138, by model year. Raw counts: years that sold more get more complaints, so this is each model year's record, not a failure rate.
Mileage when it happened
94,000 miles is the middle of what 18 owners entered. Half were between 64,000 and 138,000 miles.
The mileage on the complaint form, when the owner gave one.
What owners say caused it or fixed it
The most-named part is the throttle body, in 2 of the 18 complaints (11%). 2 of those mention it being replaced or repaired, and 2 say the problem came back afterwards.
- Throttle body2 complaints2 mention a repair or replacement, 2 of them say the problem came back · what owners paid
Counted from the owners' own words: a part counts when a sentence names it with a cause or repair word. What owners wrote, not a diagnosis. A shop should confirm the cause before replacing parts.
Symptoms owners describe with P2138
78% of these complaints say the check engine light came on.
- Stalls or shuts off11%2 of 18 complaints
Share of the complaints naming P2138 whose text also describes each problem. A complaint can describe more than one.
Recalls on these Subaru Legacy years
- Electrical · 2005, 2006 · issued 2019
The ball spring inside the switch may break, reducing the strength of the ignition switch. NHTSA 19V297000 - Speed control · 2004 · issued 2004
ON CERTAIN PASSENGER SEDANS, WAGONS, AND SPORT UTILITY VEHICLES, THE CRUISE CONTROL CABLE COULD COME OUT OF ITS TRACK ON THE CRUISE CONTROL LEVER AND LODGE ON THE CONTROL LEVER TAB WHEN THE ACCELERATOR PEDAL IS RELEASED. NHTSA 04V128000
2 recalls for the same systems (electrical and speed) on the Subaru Legacy model years above. A recall for the same system isn't proof it's behind P2138. Recall work is free at any dealer: check a VIN at nhtsa.gov/recalls or with our VIN check.
Keep going
P2138 on other cars
Subaru Outback (77) · Chevrolet Malibu (51) · Chevrolet Impala (18)
The details
How we count
We read every owner complaint in the NHTSA file whose text names this trouble code, and count the ones filed about this model (matched by the make, model and model year on the complaint). Mileage is what the owner entered on the form.
Parts: a complaint counts for a part when one of the owner's own sentences names that part together with a cause word (failed, bad, diagnosed, caused by, leaking ...) or a repair word (replaced, repaired, new, reprogrammed ...). "Came back" means the same complaint also says the problem returned or the repair didn't fix it. These are counts of what owners wrote, not a diagnosis, and one complaint can name several parts.
Complaints are reports, not proof of a defect, and most owners never file one. Popular models get more complaints, so the counts are not a failure rate. The code meaning is the standard SAE J2012 definition in our own words, or the carmaker's meaning where we verified it for that make.
What P2138 means
The two gas pedal position signals disagree, so the car may go into reduced power or not respond to the pedal.
Fix soon. Book a shop visit this week. Stop driving if the car slips, shakes, overheats or warns you.
- Failing accelerator pedal sensor
- Wiring or connector fault
- Throttle body fault
Check the complaints yourself
NHTSA complaint numbers (search them at nhtsa.gov): 11375253, 11065952, 10845775, 10823381, 10712236, 10683840, 10668625, 10606646, 10587207, 10557693, 10546660, 10508470 and 6 more.
Quick answers
What does P2138 mean on a Subaru Legacy?
Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation. The two gas pedal position signals disagree, so the car may go into reduced power or not respond to the pedal.
Which Subaru Legacy years have the most P2138 complaints?
In complaints to NHTSA, owners of the 2006 (12), 2005 (5), 2004 (1) Subaru Legacy named P2138 most (18 complaints in all, 2004–2006). Raw counts, not a failure rate.
What fixes P2138 on a Subaru Legacy?
Owners most often name the throttle body (2 of 18 complaints). That's what owners wrote, not a diagnosis: have a shop confirm the cause with a scan and tests before replacing parts.
At what mileage does P2138 show up on a Subaru Legacy?
Owners who gave their mileage reported a middle of 94,000 miles; half were between 64,000 and 138,000 (18 owners).
Can I drive my Subaru Legacy with P2138?
Fix soon. Book a shop visit this week. Stop driving if the car slips, shakes, overheats or warns you.
Sources: NHTSA owner complaints that name P2138 on the Subaru Legacy, counted by The Lemon Index; NHTSA recalls; repair bills owners named. Meanings: SAE J2012 in our own words. Owner reports, not a diagnosis or repair advice for your car.