Less than 1% of our scanners are returned faulty. Here are the most common issues that have been experienced with a Code Reader / Scanner.
Code is not in the Code Book. (*applicable to the readers that come with a 'code book'.)
If the code being displayed on the screen is not in the Code Book, it is because it is a 'manufacturer specific code'. These are custom codes created by the vehicle manufacturer and not universally accepted. The Code Book only lists 'universal codes'. The software at this link might contain the code descriptions you are looking for:
DTC Library Software: http://www.alpha-bid.com/media/Shared-Pics/DTClibrary.zip
'Error' displayed. (*applicable to the readers that come with a 'code book'.)
An 'error' display indicates that the reader is not compatible with the vehicles protocol. If the reader is not CAN-BUS enabled and the vehicle is CAN-BUS, the 'error' would display. Try it with the car started.
A blank screen may either be no power reaching your vehicles diagnostic connector or a faulty reader. Check the appropriate fuse on the vehicle or try the reader on a different vehicle.
The low cost readers have the most compatibility issues. They are designed to work on the most common models and don't have the programming to cover all protocols from all car manufacturers. From our experience, about 98% of the low cost readers we sell work fine. The other 2% experience incompatibility. Check your vehicles protocol as explained below to see if it is compatible with your low cost unit.
If a scanner we sell does not read all protocols, we will state what protocols it reads right in the items description.
To find out what protocol your vehicle uses, check for a label under the hood or...
check your vehicles diagnostic connector:
Your vehicle uses 1 of 5 possible protocols:
J1850 PWM - The connector must have pins 2, 4, 5, 10, and 16.
J1850 VPW - The connector must have pins 2, 4, 5, and 16, but not 10.
ISO 9141-2 - The connector must have pins 4, 5, 7, and 16.
ISO 14230-4 (KWP2000) - The connector must have pins 4, 5, 7, and 16.
CAN-BUS (J1939 & ISO15765-4) - The connector must have pins 4, 5, 6, 14 and 16.