Q: Fast Idle does not activate when A/C Compressor engages.

asked by on

Car idles normally at 750 rpm. However, when idling (such as at a traffic light), and the A/C Compressor engages, idle remains at 750 rpm (engine struggles) and does not advance to 1000 rpm, like it should.

My car has 70000 miles.
My car has an automatic transmission.

The idle is not supposed to increase in speed when your compressor engages, rather the throttle plate should adjust at the same time the A/C engages to maintain the same RPM at idle. This will keep the idle the same with A/C on or off. If the idle drops below 750 and then jumps real high then this is a problem and should be looked at. The throttle plate, which controls the idle speed, may need to be cleaned or inspected.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Fast Idle does not activate when A/C Compressor engages.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Kia Optima hesitates when in gear. Does not while in park. It has slowly became worse over the course of many months. It still dr

If the transmission is not faulty (e.g., clutches slipping) and thus the problem is engine related, among the possible causes of the hesitation are faults in the throttle position sensor, mass airflow sensor, vacuum leaks, a clogged fuel filter, defective...

Q: Is there any reason that a transmission fluid leak issue has to do with needing a a/c compressor replacement? 2008 Jeep Liberty

Hi there - these 2 faults are NOT connected. A transmission fluid leak will not cause AC compressor failure. You are not getting good advice from whoever told you this - not to be trusted. A transmission fluid leak can...

Q: What do I do if the coolant reservoir is completely empty?

The coolant reservoir on your Accord is connected to the radiator, and allows coolant to flow back and forth between the two as it heats and cools. If the coolant reservoir is completely empty, you can’t just refill it. You...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.