Reduced Engine Power Warning Light

Reduced Engine Power Warning Light

As car technology becomes more complicated, then the more things there are to go wrong. Most of these faults show themselves in the form of a warning light. One being an engine warning light, or ‘check engine light’ as it’s also known and inside is an arrow pointing down. Not all car manufacturers use this symbol but for those that do, it means reduced engine power, or otherwise known as ‘limp mode’.


What Happens When the Reduced Engine Power Warning Light Comes On?

Most modern cars have computers that control and monitor the engine and transmission. These are called the engine control unit (ECU) and for automatic vehicles, the transmission control unit (TCU). If the ECU or TCU detect a potentially serious fault, the reduced engine power program is initiated. This reduction in engine power is a safety function that helps to prevent damage to vehicle components. Engine speed (RPM) and certain gears may also be restricted.

Is It Dangerous to Drive with the Reduced Engine Power Light On?

The ECU or TCU has taken the necessary safety precautions by initiating the reduced engine power program, so you should be safe to drive for a limited time or distance. However, the reduced engine power program may be activated due to a serious fault that should be investigated quickly.

Why Does the Reduced Engine Power Warning Light Come On?

In certain instances the reduced engine power light illuminates simultaneously with another warning light. If this occurs, it usually makes diagnosis a much simpler process. The reduced engine power light is a generic warning that can cover many faults, so if it’s the only warning light that’s on, diagnostic code readers are usually required to locate the fault. Faults related to reduced engine power include:

  • Engine / turbo boost control
  • Engine wiring issues
  • Engine component faults
  • Faulty engine sensors
  • Faulty oxygen sensor
  • Emissions system / engine misfire
  • Transmission faults
  • Transmission wiring issues
  • Electronic throttle control (ETC) system / defective throttle position sensor
  • Brake system (the brake warning light may illuminate)