Reduced engine power is a warning that the engine computer has limited engine output, usually to protect the engine from damage. You will often see it on the driver information center, sometimes with the check engine light on.
A reduced engine power message can come from a sensor, a wiring fault or a transmission problem, so the cause is not always obvious. This guide covers the common causes, the GM bulletins that document the message, and the steps to take now.
This is general information, not a diagnosis. The cause depends on your vehicle, so confirm it with an OBD2 scan and a qualified technician.
What Reduced Engine Power Means
Reduced engine power means the engine computer has detected a fault and limited output to protect the engine. The engine control module (ECM) runs this protection. Mechanic Base calls this state fail-safe mode, or limp mode, and says it weakens acceleration and can affect shifting. In extreme cases, the page says, fuel delivery is restricted and the car may not run at all.
You may notice one or more of these signs:
- Weaker acceleration when you press the pedal
- Shifts that feel different from normal
- A reduced engine power message on the driver information center
- The check engine light, which GM bulletins describe as lit with the message
Common Causes Behind the Warning
Mechanic Base lists wiring faults, a defective oxygen sensor, throttle body problems, a failing mass airflow sensor, a clogged catalytic converter and transmission failure as common triggers. Reduced engine power is a symptom, not a diagnosis, so the same warning can have very different causes. Owners of that sedan can read Malibu power reduction codes and coverage. Transmission faults can also cut power, as transmission range sensor warning shows. Volkswagen’s version of this warning is covered in Jetta power warning causes.
The main possibilities listed on Mechanic Base are these:
- Loose or damaged wiring, connectors, clamps or ground wires
- A defective oxygen sensor
- Throttle body problems, such as a faulty butterfly valve, carbon buildup or a bad throttle position sensor
- A failing mass airflow (MAF) sensor
- A clogged catalytic converter
- A malfunctioning engine control unit
- Transmission failure
The same page’s FAQ also mentions low battery voltage and low oil level as possible factors, so check both before assuming a major failure. A scan is the fastest way to narrow the list, because stored codes point to the system involved.
GM Vehicles With Documented Cases
GM has filed bulletins for reduced engine power on specific model years, and each one covers a narrow group of vehicles rather than all GM cars. The table lists the cases in GM documents filed with NHTSA. Match your model year, model and engine before you assume a reduced engine power bulletin applies.
| Vehicle | Model years | Engine or detail | GM document | Status |
|---|---|---|---|---|
| 2013 Buick Encore, Chevrolet Sonic and Chevrolet Trax | 2013 | 1.4L turbo with 6-speed automatic | Special coverage 25160 (2016) | Special coverage, repair at no charge within the window |
| Cadillac Escalade | 2022 to 2023 | 6.2L (RPO L87) | Engineering information MC-10227059 (2022) | Not a recall |
| Chevrolet Suburban, Chevrolet Tahoe and GMC Yukon | 2022 to 2023 | 5.3L or 6.2L (RPOs L84, L87) | Same engineering information | Not a recall |
| Chevrolet Silverado and GMC Sierra | 2017 to 2018 | Engines listed in the bulletin | Bulletin 20-NA-043 (2020) | Service information for technicians |
| Chevrolet Silverado and GMC Sierra 2500/3500 | 2019 to 2020 | Engines listed in the bulletin | Bulletin 20-NA-043 (2020) | Service information for technicians |
The 2022 document is engineering information, and GM states plainly that it is not a recall. It asks technicians to contact engineering with their findings when diagnosis points to one specific condition.
A bulletin does not mean your vehicle has the condition. GM’s own text tells technicians not to assume a bulletin applies to their vehicle. Malibu and Equinox cases carry separate GM bulletin numbers and model years, and this page does not repeat them.
Cold-Weather Icing on 2017 to 2020 Silverado and Sierra
According to GM bulletin 20-NA-043, ice on the MAP sensor can trigger reduced engine power after a drive of one to two hours in freezing weather, and the message clears once the ice melts. The sequence runs like this. After a drive below freezing, ice forms on the sensor. Once the truck is stopped and idles, the ice melts. On the next key cycle, the reduced power message is gone, but the check engine light stays on with code P0106 or P140C. Another model with a documented cause is covered in Equinox charge-air connection problems.
If P0106 appears in the history and the sensor is clean and dry, the bulletin says no replacement is needed. It also warns against water, chemical cleaners and compressed air, because the sensor is sensitive. Soot does not stop it from working, and it should not be wiped off.
For 2020 model year vehicles, GM recommends a winter cover when temperatures fall below 24°F (-5°C). Other vehicles can set the same message for other reasons, so this icing mechanism applies only to these trucks.
The 2013 Encore, Sonic and Trax Turbo Case
A 2016 GM special coverage bulletin, number 25160, covers 2013 Buick Encore and Chevrolet Sonic and Trax vehicles that may hesitate and enter reduced engine power mode. Those cars had a 1.4L turbo engine (RPO LUV) with a 6-speed automatic transmission (RPOs MH8, MH9 or MHB).
According to GM special coverage bulletin 25160, the driver information center may show ENGINE POWER IS REDUCED, the malfunction indicator lamp may light, and acceleration is reduced while driving. In infrequent cases the car may stall. GM says steering and braking still work during a stall, but they may need more effort.
The repair was a reprogramming of the engine control module and the transmission control module, done at no charge within the coverage. That coverage ran for 6 years or 100,000 miles (160,000 km), whichever came first, from the original in-service date. GM estimated about 46,717 U.S. vehicles were involved. For 2013 cars, that window ended years ago, so ask a dealer what applies to a specific car.
What to Do When Reduced Engine Power Appears
Start by parking safely and checking how the car drives, then read the trouble codes with an OBD2 scanner before replacing any part. The owner’s manual section on the driver information center for your model year shows how the message appears on your vehicle.
- Find a safe place to stop and turn on the hazard lights.
- Turn the engine off once you are parked, as Mechanic Base advises when limp mode is active.
- Note the exact message on the driver information center and whether the check engine light is on.
- Read the trouble codes with an OBD2 scanner before you buy parts, since the codes narrow the system to check.
- Check the battery voltage, the oil level, and the wiring and connectors near the engine.
- If a MAP sensor is involved, do not clean it with water, chemical cleaners or compressed air.
Is It Safe to Keep Driving?
Mechanic Base says it is not recommended to drive with reduced engine power on, because the severity is unknown until the car is diagnosed. The main risk with reduced engine power is a stall. The 2016 GM bulletin says a stall can occur in infrequent cases in this mode, so waiting on the warning is a poor plan.
Stop driving and arrange a tow if any of these happen:
- The engine loses power at speed or in traffic
- The car stalls, hesitates or will not restart
- The message returns after a restart
- A scan shows codes you cannot identify
Cost depends on the cause. Mechanic Base gives a range of $0 to $2,500 as of November 3, 2026, but that is one source, so get a written estimate before you approve any work.
Frequently Asked Questions
Does reduced engine power always mean a serious problem?
Not always, but the severity is unknown until a diagnosis is done, so treat the message as a warning to check. Mechanic Base says the engine computer limits output after it detects a fault. A scan shows whether a code is stored, which helps you judge how urgent the repair is.
Can a low battery or low oil cause reduced engine power?
Mechanic Base lists low battery voltage and low oil level as possible factors in its FAQ. Check the battery and oil level first, since both are simple checks. Then scan for codes, because a stored code points to the system that needs attention.
Should I clean a sensor that may be iced or dirty?
No, not with water, chemical cleaners or compressed air. GM bulletin 20-NA-043 warns against these methods for the MAP sensor. If the sensor is clean and dry, the bulletin says no replacement is needed, and soot should not be wiped off.
Is the repair always expensive?
No, the cost of fixing reduced engine power depends on the cause. Mechanic Base gives a range from $0 to $2,500 as of November 3, 2026, which is a wide spread. Get a written estimate that names the faulty part before you approve the work.
Is reduced engine power a recall on my GM vehicle?
Not for the 2022 to 2023 Escalade, Suburban, Tahoe and Yukon bulletin, which GM says is engineering information and not a recall. The 2013 Encore, Sonic and Trax item was a special coverage program. Ask a dealer to check your VIN for open coverage or bulletins.
Will the message show up on a Chevrolet Malibu or Equinox?
Those models have their own GM bulletins with separate model years and codes, so this page does not list them. A GM dealer can check your VIN to see which bulletins apply to your car.
If reduced engine power appears, scan the codes first, then ask a dealer to check your VIN against GM bulletins for your model year. Until the cause is known, avoid long trips and highway driving, because this mode can reduce acceleration.
