Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Inspect The DLC3
The vehicle's ECM uses ISO 9141-2 for communication. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format. If there are any open or short circuits in the chart below, perform troubleshooting with the SFI System. See HOW TO PROCEED WITH TROUBLESHOOTING and HOW TO PROCEED WITH TROUBLESHOOTING on .
| Tester connection | Condition | Specified condition |
|---|---|---|
| 7 (Bus "+" Line) - 5 (Signal ground) | During communication | Pulse generation |
| 4 (Chassis Ground) - Body | Always | Below 1 Ξ© |
| 5 (Signal Ground) - Body | Always | Below 1 Ξ© |
| 16 (B+) - Body | Always | 9 to 14 V |
HINT:
If the display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the OBD II scan tool or hand-held tester to the DLC3, turned the ignition switch to the ON position and operated the scan tool, there is a problem either on the vehicle side or tool side.
- If communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
- If communication is still impossible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the tool's instruction manual.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.