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.
Diagnostic Test
TESTING LIN BUS USING THE MOPAR SCOPE
Some vehicles can have multiple LIN connections within a connector, make sure that you are testing the correct LIN circuit.
For a complete LIN BUS SYSTEM wiring diagram, refer to the appropriate Wiring Information .
- Connect the black pin for each test lead to Chassis ground. Connect the blue lead to the LIN circuit to be tested.
- Start the Mopar Scope.
- Turn the ignition on.
- Operate the systems connected to the LIN bus being tested to observe signal changes. Move connectors and wiring to look for any signal drop-out.
- When connected to the vehicle harness correctly, the LED on the breakout box will light up to indicate that there is activity on the bus.
- A waveform should appear.
The image below is of a normal LIN bus waveform using the Mopar Scope.
DESCRIPTION MEASUREMENT CHANNEL A 20 volts TIME BASE 1 ms/div [milliseconds / division control] ZOOM / VIEW X1 - HORIZONTAL & VERTICAL NOTE:The Mopar Scope has preset Guided Tests for Communications testing of the LIN bus.
- The waveform should reveal that data is being exchanged continuously along the LIN bus and the peak voltages are correct.
- Determine the type of LIN waveform fault (short, open, etc.) the vehicle presently has.
Did the Mopar Scope show the LIN bus waveform fault?
- Use the wiring diagrams as a guide to follow the path of the circuit(s) to isolate the fault further and then repair / replace as needed.
- The condition that originally caused the concern may not be present at this time.
- Continue to use the Mopar Scope and wiring diagrams as a guide to trace the circuits and look for any in-line connectors where the fault could occur intermittently by wiggling the wire harness and connectors.
- Look for any chafed, pierced, pinched, or partially broken wires.
- Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related wire harness connectors.
- Perform any Technical Service Bulletins (TSBs) that may apply.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.