What to Do If a Car Fails the Exhaust Emission Test?

2 Answers
DelPaislee
07/28/25 10:02pm
Insufficient ignition energy from spark plugs fails to completely burn the air-fuel mixture, resulting in excessive HC content in the exhaust. Poor atomization of fuel injectors or an overly rich air-fuel mixture can also lead to excessively high pollutant levels in the exhaust, causing the vehicle to fail the test. Therefore, it is essential to clean the fuel injectors regularly. The advantages of high-octane gasoline are mainly reflected in "two highs and two lows": higher anti-knock performance and power output, along with lower harmful substances in gasoline and reduced exhaust pollution. Neglecting the maintenance of the three-way catalytic converter can lead to its blockage, reducing its ability to convert harmful gases and ultimately causing the vehicle to fail the exhaust emission standards.
Was this review help?
18
3
Share
Marvin
08/12/25 2:36am
A few days ago, my old car also failed the emissions test, so I hurried to my regular repair shop. The mechanic said the issue might be with the catalytic converter or oxygen sensor, as being too dirty or failing can cause excessive emissions. He first did a simple check, like seeing if the engine light was on, and then suggested cleaning the intake system and fuel lines to try—excessive carbon buildup causing incomplete fuel combustion often leads to this. The cleaning cost was around 300 yuan, not too expensive; if that didn’t work, parts would need replacing, which is costlier. Regular maintenance is crucial—I always change the air filter and oil on time and use higher-quality gasoline to prevent many issues. If you fail the test, don’t panic; find a reliable repair shop, fix it, and retest—it usually passes. Ignoring repairs will cause trouble and fines at the next inspection. Remember, safety first—don’t drive on highways recklessly.
Was this review help?
5
5
Share
Expand All
More Forum Discussions

Does the car need to be driven for license plate registration?

The car must be driven over for license plate registration. Below are the specific procedures for vehicle license plate registration: 1. Pay purchase tax: Vehicle purchase tax needs to be paid, new car insurance purchased, and criminal investigation inspection conducted. 2. Vehicle exterior inspection: Non-exempt vehicles undergo line inspection, payment and form filling, number rubbing and photo taking, data collection to obtain license plate materials. You need to submit materials at the vehicle management office hall, owner signs, police conduct vehicle exterior inspection and confirmation. 3. Install license plate: Select number and receive receipt, fix license plate seal, receive vehicle license and registration certificate. With complete materials, car license plates can generally be obtained on the same day.
6
2
Share

Does backing out of the line during parallel parking result in penalty points?

Backing out of the line during parallel parking results in penalty points. The driver must park the vehicle into the right parking space without the wheels touching the lane boundary or parking space boundary. Below are the key points for parking: 1. Drive slowly parallel to the parking space and stop when pole No.1 appears in the rear window; 2. Shift into reverse gear, honk once, turn on the right turn signal, and prepare to reverse into the space; 3. While reversing, when the center of the small triangle in the right rear window aligns with pole No.1, turn the steering wheel one and a half turns to the right and immediately check the left rearview mirror; 4. Stop when both sides of the front of the car are between poles No.1 and No.2 (there is no need to straighten the steering wheel; maintain the position when stopping).
14
2
Share

What does a triangle with an exclamation mark mean in a car?

The exclamation mark inside a triangle displayed on the car dashboard is a general fault warning light. The reasons for its illumination are as follows: 1. The color is usually red, and it lights up for 2 seconds during power-on self-check before turning off. 2. It lights up when there is a fault in the fuel injection system. 3. For general faults, the warning light remains lit. 4. For severe faults, the warning light flashes. 5. The warning light automatically turns off once the fault is resolved. Common faults that trigger the general fault warning light include: 1. Overheating of the dry dual-clutch transmission or clutch. 2. Intervention or malfunction of the fuel cutoff system. 3. Fault in the parking sensor. 4. Fault in the engine oil pressure sensor. 5. Warning or fault in the traction control system.
3
4
Share

How to Repair BMW Stalling When Shifting from D to N?

BMW stalling when shifting from D to N can be resolved by rematching the automatic transmission control unit with the gearbox. Below is relevant information about BMW: 1. Introduction to BMW: BMW, fully known in Chinese as Bavarian Motor Works, is a German luxury automobile brand. BMW was established on March 7, 1916. Originally an aircraft factory, BMW initially gained fame for manufacturing streamlined biplane reconnaissance aircraft. Its predecessor company was named BFW, and its founder was Gustan-Otto. 2. Meaning of the BMW Logo: B.M.W. stands for Bavarian Motor Works. The colors and design of the logo are derived from the coat of arms of Bavaria, where BMW is headquartered. The blue and white pattern serves as a reminder of BMW's pure Bavarian heritage.
18
5
Share

What to Do When It Rains in a Soft-Top Convertible?

Here are the solutions for dealing with rain in a soft-top convertible: 1. First, find a suitable place to park. Alternatively, slow down the vehicle to allow the soft top to be opened. 2. Manual soft-top convertibles require manually closing the roof. For automatic soft-top convertibles, simply press the hardtop button to automatically close the roof. 3. Drive the car directly into a garage. 4. Spoiler-like devices. Some convertible models feature a spoiler-like device at the top of the windshield, which can effectively keep rainwater out of the cabin. 5. Use an umbrella. If temporary equipment fails, the passenger can hold an umbrella while driving in the rain.
8
1
Share

What are the requirements for upgrading from a C1 to an A2 driver's license?

To upgrade from a C1 to an A2 driver's license, the following conditions must be met: 1. The applicant must be between 24 and 50 years old. 2. The driver must hold a C1 license for at least one year, and during the probation period, the driver is prohibited from upgrading. 3. After one year, the driver can register for the exam. Upon successfully passing the test, the driver will obtain a B1 or B2 license. 4. The driver must hold the B1 or B2 license for at least three years, without accumulating 12 penalty points in any two scoring cycles, or hold an A1 license for more than one year without accumulating 12 penalty points in the most recent year, before being eligible to apply for an A2 license separately.
14
0
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.