UNDERSTANDING CHASSIS/VIN, DLC/OBDII AND FAULT CODE DESIGNATION
Good day Friends and colleagues, we will be looking at three different topics in this article. The meaning of your VIN number and its importance, the DLC connector and designation and lastly Fault code designation. Reason being that without proper understanding, we will find it very difficult to relate fault codes to symptoms and eventually the fix as specified by the manufacturer.
The Chassis/VIN (Vehicle Identification Number).
In the bid to manufacture an ideal vehicle, manufacturers are saddled with the responsibility of being constantly innovative, having the Environment, Performance and Comfortability at the back of their mind, because of these reasons; changes, modifications and corrections are a continuous process. This implies that information of yesterday can never be relied on, it is better to always find the correct specification and procedure per time.
This can be achieved by understanding the VIN of the vehicle you are driving or dealing with.
The Chassis/Vin number is a unique and important alpha-numeric identification number usually stamped on a plate attached on the left side of the dashboard just inside the windshield on the driver’s side of the vehicle, by the drivers door or on the seat belt, the numbers in all these three location must be the same. This is usually the first point to get the correct information on the vehicle.
The Chassis or VIN number for vehicles manufactured between 1974 through 1980 was 11 digits, though this has being changed to 17 digits since 1981 to date. All modern vehicles from 1981 has with 17 digits as their VIN.
The VIN for each manufacturer is unique, the alpha-numeric 17 digits are represented to mean a lot with respect to understanding the vehicle in terms of repair and usage.
Example: For this particular brand, below is the respresentation of the VIN;
1FT R E11 W O 7 D A00001This manufacturer decided to divide the VIN into 8 parts for easy understanding of its brand.
- The first three alpha-numeric represent World Manufacturer Identifier(WMI)
- The 4th alpha-numeric represents Brake Type and Gross Vehicle Weight Rating (GVWR)
- The 5th to 7th alpha-numeric represents the Vehicle Line, Series and Body-type.
- The 8th alpha-numeric represents Engine Type
- The 9th alpha-numeric represents the Check Digit
- The 10th alpha-numeric represents the Model Year
- The 11th alpha-numeric represents the Assembly Plant
- The 12th through 17th alpha-numeric represents the Production Sequence Number.
In all these digits the only common representation amongst all brands are the First Three, the Nineth and Tenth digits.
The others can be represented by the manufacturer in their best possible way but in conformity with the SAE/ISO standards, as shown in Fig 1a.
The DLC(Diagnostic Link Connector)/ OBD II(On Board Diagnostic) connector.
In the bid to extract fault codes and access real live data for proper inspection and repair of the vehicle, the need arose to have a communication path between the OBD II scanner, DLC 3 connector and the ECU/PCM/ECM. The DLC/OBD II connector is a 16 pin connector located at least 2ft from the steering. Out of the 16 pins, 7 have standardized definition as specified by SAE and ISO, these pins include:
- Pin 2: Communication Bus(+)
- Pin 4: Chassis Ground
- Pin 5: Signal Ground
- Pin 7: ISO K line
- Pin 10: Communication Bus(-)
- Pin 15: ISO L line
- Pin 16: Battery.
The other pins are Discretionary, meaning it can be used by Manufacturers with respect to specified functions by design. As shown in Fig 1b.
Fault Code Designation:
As we have always said, that the auto diagnostics scanner, be it Basic, Elite or Pro models does not fix issues in vehicles, it only gives the technician an insight into the issues the vehicle is having, your expensive scanner can only be worth the price if it is effectively utilized. For effective utilization we must understand what each code means, which ensures proper application of results to fixing vehicle issues as specified by the manufacturer.
Fault Codes are represented in the format below:
- PXXXX: (Powertrain related codes)
- BXXXX: ( Body related codes)
- UXXXX: (Communication related codes)
- CXXXX: (Chassis related codes)
These are different Systems in the vehicle.
The 1st X could either be a 0, 1, 2 and 3 meaning the standard applied (SAE/Generic or Manufacturer), while the 2nd X could be 1, 2, 3, 4, 5, 6, 7, 8, 9 meaning the Sub-systems, while the 3rd and 4th X indicate the component location.
Using PXXXX as an example which applies for the B, C, and U except for the applied standards which has a little deviation.
PXXXX:
Explanation for the 1st X:
P0XXX Generic(SAE)
P1XXX Manufacturer
P2XXX. Generic(SAE)
P30XX …. P33XX Manufacturer
P34XX …..P39XX Generic(SAE)
Explanation for the 2nd X:
PX0XX Air/Fuel Sub-systems
PX1XX Air/Fuel Sub-systems
PX2XX Fuel metering Sub-system(Injectors)
PX3XX Ignition Sub-system
PX4XX Auxiliary Emission Controls Sub-systems
PX5XX Idle Speed/Wheel Speed Control Sub-systems
PX6XX Computer communications Sub-systems
PX7XX Transmission Sub-systems
PX8XX Transmission Sub-systems
PX9XX Transmission Sub-systems
Explanation for the 3rd and 4th XX
PXX00 this indicates the Faulty Component location, this part is the same for the other explanations.
Application:
P0303
The code means that, there is a misfire in the third cylinder of the ignition sub-system in the Powertrain system. As shown in Fig 1c.
A proper understanding of this will lead to effective application of our auto diagnostic scanners and resource materials.
For more detailed, educative information kindly signup on our website www.automatononwheels.com or Like our facebook page; Automaton On Wheels page.
Feel free to ask questions.
No knowledge is lost… You’ll never know when it will come handy.
Automobile repair has gone past the days of less thinking and more loosening.
Be a Fixer not a part fitter…. STAY DIRTY.
