A Reduced Power light usually indicates a fairly serious problem with the throttle system. When this light illuminates the vehicle will often go into a “safe mode”, which will severely limit the speed of the car and in some cases will render the vehicle un-drivable.
Since the Reduced Power light can trigger for a number of different reasons, tracking down the exact cause is extremely important, if the vehicle is not properly diagnosed and repaired, the Reduced Power light will trigger again, putting the vehicle in safe mode.
How this system works:
When the vehicle’s computer detects a fault in the engine that affects its drivability, performance, transmission or emission system it will trigger the reduced power light. It will also trigger if there is an issue with the electronic throttle, the accelerator pedal or the throttle module.
When a vehicle goes into reduced power mode it will seriously impact its performance. Some vehicle will be restricted to idle speed while others restrict speed to 20-30 miles per hour. The Reduced Power trigger will save Diagnostic Trouble Codes (DTCs), which will indicate where the fault occurred. In most cases, a Restricted Power light is related to a throttle body or the connector.
Common reasons for this to happen:
Faulty Throttle Body: A throttle body is part of the of the air intake system which helps control the amount of air going into the engine. If a throttle body is failing the engine will not get the correct mixture of air and fuel. This can trigger the Reduced Power light as well as lead to a poor running engine. It can also trigger the Check Engine light.
Failing Throttle Position Sensor: The throttle position sensor tells the vehicle computer the position of the gas pedal. The computer uses this information to calculate the proper amount of air and fuel to send to the engine. The throttle position sensor also controls shifting the gears of a vehicle, which means that a faulty throttle position sensor will prevent a car from changing gears. If this part is failing, the Reduced Power light will trigger.
Faulty Engine Control Unit: The engine control unit is an essential component of a vehicles computer. It regulates and controls many systems, including the drive train and parts of the engine. If a fault is detected in this crucial part, it can trigger the Reduced Power light as well as the Check Engine light. This is a major issue that should be investigated as soon as possible.
Faulty Wiring: Exposed or damaged wires can cause issues with the any of these components and will possibly trigger the Reduced Power light. A loose wiring crimp can also be the culprit. Wiring issues can be tricky to track down so using a professional mechanic is a necessity.
Malfunctioning Oxygen Sensors: Oxygen sensors are responsible for measuring how rich or lean exhaust gases are leaving a vehicles combustion chamber. The vehicle’s computer uses this information to constantly adjust the amount of fuel going into the engine. A failing or dirty sensor can put too much or too little fuel into the engine. While a failing oxygen sensor will usually trigger a Check Engine light it is possible that the Reduced Power light could also trigger.
What to expect:
A top-rated mobile mechanic will come to your home or office to determine the source and cause of the Reduced Power light issue, and will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.
How it's done:
The mechanic will inspect your vehicle's air intake system, electrical wiring and sensors, including the throttle body and oxygen sensors, along with other important components. It may be necessary for the mechanic to test drive the car to verify the complaint and provide an accurate diagnosis.
How important is this service?
The Reduced Power light only illuminates if there is a serious issue with the vehicle that must be addressed immediately. In almost all cases, the throttle or the vehicles computer will be malfunctioning which can make driving the vehicle dangerous. While it varies by manufacturer, most vehicles that go into “safe mode” will stay there until the error codes are read by a code scanner.
If the vehicle Reduced Power light illuminates the vehicle should immediately be inspected, diagnosed and repaired.