Buy Now | Log In | ALLDATA Corporate Site |
Back To Home Page
Log In To Your Subscription
Go To ALLDATA Back Home
Buy A Subscription! Back Home About ALLDATA Information View Sample Vehicles Read Testimonials View Factory Service Bulletins and Recall Titles Contact Us
Dowload Our Navigation Chart
February 2015: New vehicles added including 2014 GM.
• View New Vehicles
October 2014: Release of 2013 along with initial 2014 Vehicles
• View Vehicles
View All News and Updates:
• Go To News
Tech Tips
  Read All Tech Tips

ALLDATA Tech Articles Are Updated Weekly
• View All Tech Articles

  Dodge Durango: Brake Pulsation Problems In Paul's Durango
• Read Dodge Article
Fixing A Smelly Audi Audi Tech Tip: A4 begins to Smell caused by a Faulty Hose Composition
• Read Audi Article
Why Do You Need To Change Your Timing Belt? Why Replace Your Timing Belt
• Read Belt Article
Jim Grant Tech Tips Jim Grant Tech Tips
A collection of helpful articles based on reader submissions
Home >> Featured Tech Articles >> Go Back
  Jim Grant's Tech TipsJim Grant's Tech Tips
Below is a collection of Jim Grant's Tech Tips sorted by Vehicle Make. These Tech Tips were answers to questions submitted to Jim by users over the course of many years.
If you have any questions, please feel free to email us.



Lincoln - Mercury
  Jim Grant's Tech Tips

’00 Hyundai Accent, Computer Code Reading P1128

Q: I own a ‘00 Hyundai Accent with computer code P1128. I understand this code means low fuel trim, running lean. The fuel injectors, fuel pump and pressure regulator were checked and found to be good. The computer grounds were checked and all was good. Could the O2 sensors be bad even though there is no code? It’s my son’s car and he needs it for college.


A: Yes, a loose or defective O2 sensor can cause this code to be set. But, the more common causes for the computer code you’re reporting is due to vacuum leaks. Here are the conditions that have to be met before this particular code can be set, (turn the check engine light on). First the long-term fuel trim value goes to 10% to 15% lean for 30 seconds during two driving cycles. Then the following has to be in place 1; Engine load exceeds 1.8 milliseconds. 2; Engine coolant temperature is above 158 °F. 3; The canister purge system is not operating. 4; Mass air flow is less than or equal to 5.5 g/s and last but not least the engine speed is below 1000 RPM. Basically, this code will only set if the engine is at or near idle speed. The problems caused by vacuum leaks are most pronounced at low engine RPM. With this information, you can understand why checking for a vacuum leak is first. If no vacuum leaks are found you have to next be sure that the exhaust has no leaks. Exhaust leaks at the manifold, front pipe and converter will cause the O2 sensor to report false information, resulting in the computer reporting false codes. Vacuum leaks and exhaust leaks are the more common causes for this type of computer code. More often than not it is the simple things that cause the bigger problems.

Have any Questions About Please Email Us
Buy Now | Log In | About | Sample Vehicles | Testimonials | Join Affiliate Program