P2127: Throttle/Pedal Position Sensor/Switch E Circuit Low
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Surface streets only, same as its twin P2122 - one pedal sensor down keeps the car moving, but the failure mode's next step is idle-only, so stay off the highway until fixed.
Symptoms
- Reduced power warning
- Soft or unresponsive pedal
- Possible idle-only mode when paired with a D-sensor code
- May be intermittent with a chafed harness
Likely causes, most common first
- Accelerator pedal position sensor E failed
- Wiring open or shorted to ground
- Connector corrosion
- Shared 5-volt reference pulled down by another component
Read P2127 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P2127 is the E-channel twin of P2122 - the second of the pedal's two sensors reading below its plausible range. Everything about the D-sensor diagnosis carries over: verify the 5-volt reference before condemning the pedal, and suspect wiring when the fault comes and goes.
The combination case matters most: P2122 and P2127 together, both channels low at once, is almost never two sensor tracks dying simultaneously. It is one shared cause - a common connector, a common reference wire, or water inside the pedal connector shorting both signals. Cars that wade through deep water or live where cabins leak collect exactly this pair, and the cure is drying and sealing a connector, not a parts bill.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P2127
“The jeep had a p2138 code which is pedal sensor bad and p2127 took to black dodge jeep they found it bad replaced with OEM part 800 mi later p2138 code is back on and takes off on it's own”2018 Jeep Wrangler · Apr 2023
“Service stabilitrak message displayed and reduced engine power to 0 mph while driving. Throttle body, Accelerator pedal position sensor (whole pedal assembly), and ecm replaced. Issue continues. P2138, P2122, P2127 codes present. Stonebriar chevrolet incompetent to resolve.”2010 Chevrolet Impala · Aug 2021
“While driving received recurring check engine light for p2127/p2138 code. Has been to Quirk Chevrolet twice previously for same issue, drives fine for a week or two and light comes back. Third service appointment scheduled for Monday 6/7/21. Recurring issue has made vehicle unusable while effected as car goes into limp mode while in motion limiting speeds to 25mph which was interesting to say the least as it happens while in motion.”2017 Chevrolet Malibu · Jun 2021
Show 7 more owner reports
“Cruising to work on I-93 in concord, nh traveling around 70 mph and it just lost power again!!! The "reduce engine power light" came on and vehicle would only go 25-30 mph. Thankfully there wasn't a vehicle behind me. I would have been "killed". Dropped vehicle to chevy dealer. They found p2127 for accelerator pedal position sensor failure, replaced gas pedal, cleared codes, road testes. Mileage 76,473. This is absolutely and totally unsafe and unacceptable. The vehicle is in the shop again for the fourth time, same issue. I will report each incident separately. *tr”2017 Chevrolet Malibu · Mar 2020 · 76,473 mi
“Cruising to work on I-93 in concord, nh traveling around 65 mph. I went out into the passing lane and the car totally lost power. The "reduce engine power light" came on and vehicle would only go 25-30 mph. Thankfully there wasn't a vehicle behind me. I would have been "killed". Dropped vehicle to chevy dealer. They found p2127 stored in system, reset ecm road tested and could not duplicate any faults. Mileage 75,698. This is absolutely and totally unsafe and unacceptable. The vehicle is in the shop again for the fourth time, same issue. I will report each incident separately. *tr”2017 Chevrolet Malibu · Jan 2020 · 75,698 mi
“Engine power reduced. Engine power reduced. At first it seemed to happen when it was raining, but on dry days no problems. The engine light comes on, and disappears a few hours later. The dealership acts as if they can't tell you anything once the warning and engine light turn off. Lately it's been happening more frequently, so I was finally able to get it read. Error codes p2138 and p2127, both referencing throttle/pedal position sensor. Seems to be the only complaint I see on here. I also have read about law suits being filed regarding this as well.”2017 Chevrolet Malibu · Jan 2020 · 56,000 mi
“I was driving and my car started to reduce speed, hesitate, and jerk when put my foot on the gas at a light to pull off or even with my foot on the gas pedal driving. My car couldn't pick up speed past 25 miles and sometime less. A message came up on my dash board stated flashing reduce engine speed. I was near auto zone when it happened so I asked to have a dianostic completed and it stated throttle/ pedal position sensor/ switch "e" circuit low input meaning code p2127.”2008 Pontiac G6 · Jun 2019 · 111,540 mi
“I cranked my 2009 chevrolet impala leaving a nearby gas station and the message service traction control flashed, then engine power reduced, and the check engine light came on. My car drove sluggish home at a very slow speed. Luckily I was only about 5 minutes from home. The next morning no message was displayed and the check engine light went off. I took it to advance auto parts and the code p2127 was displayed twice - throttle pedal position sensor. I see most of these complaints are similar to mine I just happen not to be on the highway. Is gm investigating this because this is serious with multiple occurrences? *tr”2009 Chevrolet Impala · Aug 2014 · 126,000 mi
“Vehicle will not operate over 1,000 rpm. It had the throttle body cleaned on 15 aug 2013 under customer satisfaction recall 12n03. For the original complaint, the idling spiked where in this instance the car will not accelerate above 1,000 rpm. The codes associated with this incident are: p060b; p061b; p0122; p0155; p0222; p0316; p0480; p2104; p2110; p2122; p2127; p2132; p2135. *tr”2007 Ford Freestyle · Jan 2014 · 145,000 mi
“While driving, the check engine and esc lights illuminated. Vehicle had sudden loss of acceleration and would not go beyond 40mph. Speed decreased below 40mph on hills. Vehicle continued to have problems even after restarting. A check of the odb-ii codes gave p2138, p2127 and p2106. All of the codes reflect a malfunction in the accelerator control system. Awaiting repairs by local kia dealer. *tr”2008 Kia Sorento · Aug 2012 · 27,534 mi
Cars that report P2127 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P2127?
Surface streets only, same as its twin P2122 - one pedal sensor down keeps the car moving, but the failure mode's next step is idle-only, so stay off the highway until fixed.
How much does it cost to fix P2127?
Typical US repair costs range from $60 for the simplest fix (accelerator pedal assembly) to $450 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P2127. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.