Testing your OBD2
Before You Begin
all vehicles are not the same please refer to the manual supplied with
the OBD2 code reader for vehicle specific instructions.
Is your vehicle compliant?
cars and light trucks manufactured since late 1995 should be OBD2
compliant. Two factors will show if your vehicle is definitely OBD2
- There will be a note on a sticker or nameplate under the hood: "OBD2 compliant”
- There will be an OBD2 connector as shown below
Pin 2 - J1850 Bus
Pin 4 - Chassis Ground
Pin 5 - Signal Ground
Pin 6 - CAN High (J-2284)
Pin 7 - ISO 9141-2 K Line
Pin 10 - J1850 Bus
Pin 14 - CAN Low (J-2284)
Pin 15 - ISO 9141-2 L Line
Pin 16 - Battery Power
Where is the connector located?
connector must be located within three feet of the driver and must not
require any tools to be revealed. Look under the dash and behind
Important info about OBD2
diagnose/check engine problems in all CAN and OBD2 vehicles (1996 and
newer) and many of the most popular OBD1 (1981 to 1995) vehicles
- Features unique patented all-in-one screen display and LED display for quick emissions check
- Automatic refresh updates data every 30 seconds when connected to the vehicle - an easy way to verify repair completion
- Code definition can be displayed in English, French and Spanish
- Can be Flash updated with a standard Windows® PC
- Features memory/battery backup for off-car review and analysis
the OBD2 Code Reader is as simple as locating the DLC connector. The
DLC connector is usually found under the driver side (left side) of the
dash. The cable attaches only one.
Reading the LCD Display
Click to enlarge
you start testing, take a good look at the LCD display. The
illustration above explains what the various icons mean and how the DTC
(Diagnostic Trouble Code) will be displayed. The unit is self-powered
by three-AAA batteries and will let you know when they are running low.
When connected/receiving power from the vehicle, the CAR Icon will
The OB2 code reader is a very simple tool to
use. Once it is connected, turn the power on. Once the ignition is
switched to the on position, the code reader is checking the system for
any stored DTCs.
The meaning of each DTC can be found in the manual supplied with your code reader.
Example: the code reader displays a DTC PO309, Cylinder 9 misfire was detected.
Engine Oil Over Temperature
Random/Multiple Cylinder Misfire Detected
Cylinder 1 Misfire Detected
Cylinder 2 Misfire Detected
Cylinder 3 Misfire Detected
Cylinder 4 Misfire Detected
Cylinder 5 Misfire Detected
Cylinder 6 Misfire Detected
Cylinder 7 Misfire Detected
Cylinder 8 Misfire Detected
Cylinder 9 Misfire Detected
Cylinder 10 Misfire Detected
Cylinder 11 Misfire Detected
Once you know what the
problem is, you have to determine what's causing it. In this case the
intake manifold gasket was faulty. Once the repairs have been made, it
is time to clear the DTC and check the system to verify the repair.
Clearing the Diagnostic Trouble Code (DTC)
Clearing the DTC is very simple. Press the ERASE button on the code reader. A message will display on the screen; "SURE"
for conformation. If you wish to clear the DTC press and hold down the
ERASE button again until a message appears on the screen "DONE"
. If you did not wish to clear the codes and hit Erase by mistake at the screen message "SURE"
simply press the link button to return without erasing any DTCs.
you clear the DTC(s) from the PCM (Power train Control Module)you also
clear ALL of the other gathered information that the PCM has collected,
including Freeze Frame, Drive Cycle data, manufacture specific enhanced
data end everything stored in memory is erased - just like if you
cleared the Cache files on your PC.
The vehicle's PCM
will need to re-learn the information that was erased. Don't be
alarmed!! This is easily accomplished just by driving the vehicle. All
you have to do is get driving.
Good luck and check the OBD 2 connection port.