What Causes High Idle Speed in Cars?

1 Answers
LeElijah
07/29/25 4:05pm
Here is a detailed explanation of the causes and solutions for high idle speed in cars: 1. Throttle valve sticking or not closing properly: If the engine idle speed drops to normal when the throttle lever is pushed in the closing direction, it indicates throttle valve sticking or improper closure. Solution: Replace the cable, remove the sticking parts, and clean the throttle body. 2. Additional air valve malfunction. Solution: Replace the additional air valve. 3. Idle speed control valve failure: Check for the sound of the idle speed control valve operation. If there is no sound, the control valve is faulty. Solution: Replace the control valve. 4. Water temperature sensor failure. Solution: Input an artificially low water temperature signal to the ECU. 5. Air conditioning switch or power steering pressure switch failure. 6. Crankcase forced ventilation valve failure. Solution: Replace the crankcase forced ventilation valve. 7. Air intake system leakage. Solution: Locate the leak, reseal or replace the relevant components. 8. Generator charging voltage too low. Solution: Inspect and repair the engine.
Was this review help?
16
0
Share
More Forum Discussions

Do LED headlights require a ballast?

Most LED headlights do not require a ballast, but in practice, it is necessary to analyze based on the specific vehicle model. For example, the LED bulbs of the Teana come with a built-in ballast, so replacing the LED bulbs also requires replacing the ballast. The principle of the ballast: it instantly converts 12V current into high voltage and maintains stable high voltage. This high-intensity voltage is used to activate the HID bulb to produce strong light between the two electrodes, achieving high-brightness illumination. The functions of the ballast: 1. It has a cold-start current of less than 6.5A, ensuring fast startup; 2. It features a wide-voltage design, ensuring normal startup under both low and high voltage conditions.
12
2
Share

When is the toll-free period in 2020?

According to the official notice issued by the Ministry of Transport, from 0:00 on February 17 until the end of epidemic prevention and control efforts, all toll roads nationwide will be exempt from tolls. Other toll-free periods remain consistent with previous years' regulations. Below are the details regarding the highway toll exemption: 1. Scope of exemption: The vehicles eligible for toll-free passage are passenger vehicles with 7 seats or fewer (including 7 seats) traveling on toll roads, including motorcycles permitted to travel on ordinary toll roads. 2. Toll-free sections: The toll roads eligible for toll-free passage are those that comply with the "Highway Law of the People's Republic of China" and the "Regulations on the Administration of Toll Roads," and have been legally approved as toll roads (including toll bridges and tunnels). Whether airport expressways in various regions implement toll-free passage is determined by the provincial (autonomous region, municipal) people's governments.
11
4
Share

What Causes the Engine Temperature to Rise by One Bar When Driving on the Highway?

When the car's engine temperature rises by one bar while driving on the highway, the possible cause could be a faulty thermostat leading to insufficient opening, resulting in poor coolant circulation. Here is more information about the car radiator: 1. Introduction: The car radiator, also known as the heat exchanger, is a key component of the car's cooling system and part of the engine assembly. 2. Function: Its purpose is to dissipate heat. The coolant absorbs heat in the water jacket, flows to the radiator to release the heat, and then returns to the water jacket for circulation, achieving temperature regulation. 3. Working Principle: When the engine's temperature is high, the water pump circulates the coolant repeatedly to lower the engine's temperature and protect it. In winter, if the coolant temperature is too low, the circulation stops to prevent the engine from becoming too cold.
8
1
Share

Is the Smell in a New Car Formaldehyde?

New car smell is formaldehyde. Here are the relevant details:1. Material adhesives: Formaldehyde is colorless and odorless, but new cars contain formaldehyde. The peculiar smell in cars generally comes from air pollution inside the vehicle, which mainly originates from various decorative materials throughout the car, such as roof felt, leather seats, plastic materials, etc. These materials commonly use adhesives containing formaldehyde, benzene for coloring, and plastic components may contain formaldehyde. 2. Odor removal: In addition to simply spraying formaldehyde treatment, activated charcoal can also be used by placing several packets and replacing them regularly. If conditions permit, a specialized formaldehyde air purifier can be installed in the car to absorb formaldehyde. The best method is to ventilate the car to remove formaldehyde, reducing the concentration of pollutants inside and allowing harmful gases to dissipate quickly.
2
1
Share

What Vehicles Are Considered Commercial Vehicles?

Commercial vehicles refer to those engaged in social transportation and charging freight, or those used for commercial delivery or transportation purposes. Conversely, non-commercial vehicles include those used by party and government agencies, social organizations, enterprises, and institutions for their own purposes, or vehicles solely for personal or family use. For vehicles with dual-use purposes, they are treated as commercial vehicles when purchasing insurance. More information about commercial vehicles is as follows: 1. Required documents. Copies of the approved "Vehicle Purchase Application Form" and "Commercial Vehicle Purchase Approval Form," vehicle license, additional purchase tax certificate, and purchase invoice. 2. Application process. The initial review is conducted by the Municipal Transport Management Section, followed by a re-examination by the Guangzhou General Station. After approval, the "Operating License" is issued, and the vehicle owner must pay the transport management fee at the relevant traffic management office with the vehicle license to obtain the certificate.
18
2
Share

What are the tips for curve driving in the second subject of the driving test?

The tips for curve driving in the second subject of the driving test are: 1. Slow down in advance and keep to the right when entering the curve; 2. Do not turn the steering wheel too quickly or sharply; 3. Choose a driving route with as large a turning radius as possible; 4. Avoid using the brake, especially emergency braking; 5. Learn to use the rearview mirror and master the clutch well, using the half-clutch linkage. The second subject, also known as the small road test, is part of the motor vehicle driver's license assessment and is the abbreviation for the field driving skill test subject. The test items for cars C1 and C2 include reversing into a garage, parallel parking, stopping and starting on a slope, turning at a right angle, and curve driving.
12
3
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.