Reduced Power - Limp Mode

The computer system that controls your car has a built in safety feature called Reduced Power or Limp Mode which is designed to get the car where it is going but under low engine power. If a glitch appears in the operating system that controls vital components such as the throttle actuator the computer will go into a Power Reduction (limp) before a check engine light can be triggered. Most of the time it takes being in this mode for some time before the check engine light will illuminate.

What goes wrong?

As a car ages it begins to developed a substance call Coking which resembles a thin brown tar on its throttle bore actuator and butterfly. When this happens the response time between the throttle pedal sensor and the actuator increases causing a problem. This condition can be accompanied by either throttle pedal or throttle actuator trouble codes. Other systems can create a limp mode condition, this is the most popular by far.

Where is it?

The throttle actuator bore is located at the inlet of the intake manifold under the hood.

What's the cost?

The cost for this repair is surprisingly inexpensive. You will need throttle bore cleaner and shop towels which together will run about $22.00 (US) at any auto parts store or Amazon.

Reduced Power Repair

  • Scan PCM for codes (if any)
  • Disconnect battery
  • Remove air intake tube
  • Remove throttle actuator
  • Clean thoroughly using throttle bore cleaner
  • Reinstall throttle bore and air intake
  • Reconnect battery
  • Clear any codes present

Let's Get Started

  1. Starter by disconnecting the battery, this will prevent triggering computer issues when doing the repair. Locate the air intake tube and loosen the clamps and mounting bolts to remove it.
  2. Remove the actuator wiring connector which could have a safety clip that will need to be removed before the connector can be disconnected.
  3. Some actuators have coolant running through them which will need to be drained and then refilled once the job is complete. Disconnect the hoses and continue to removing the mounting nuts.
  4. Clean the throttle actuator bore housing and butterfly both the front and back sides including the pivot shaft. Once clean reassemble the way it came apart and clear the codes if necessary. 

Watch the video!

How to Service Reduced Power Problems


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