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.
Diagnosis Procedure
- CHECK PRE-CRASH SEAT BELT CONTROL UNIT INPUT SIGNAL
Check that voltage between seat belt buckle switch (passenger side) and ground.
(+) (-) Condition Voltage (V) (Approx.) Seat belt buckle switch (passenger side) Connector Terminal B553 35 Ground When driver side seat belt is not fastened 5 When driver side seat belt is fastened 0 Is the inspection result normal?
YES: Seat belt buckle switch (passenger side) circuit is normal.
NO: GO TO 2.
- CHECK SEAT BELT BUCKLE (PASSENGER SIDE) SWITCH CIRCUIT
- Turn ignition switch OFF.
- Disconnect pre-crash seat belt control unit (passenger side) connector and seat belt buckle switch (passenger side) connector.
- Check continuity between pre-crash seat belt control unit (passenger side) and seat belt buckle switch (passenger side).
Pre-crash seat belt control unit (passenger side) Seat belt buckle switch (passenger side) Continuity Connector Terminal Connector Terminal B227 6 B553 35 Existed - Check continuity between pre-crash seat belt control unit (passenger side) and ground.
Pre-crash seat belt control unit (passenger side) Ground Continuity Connector Terminal B227 6 Not existed Is the inspection result normal?
YES: GO TO 3.
NO: Repair or replace harness between pre-crash seat belt control unit (passenger side) and seat belt buckle switch (passenger side).
- CHECK SEAT BELT BUCKLE SWITCH GROUND CIRCUIT
Check continuity between seat belt buckle switch (passenger side) and ground.
Seat belt buckle switch (passenger side) Ground Continuity Connector Terminal B553 41 Existed Is the inspection result normal?
YES: GO TO 4.
NO: Repair or replace harness between seat belt buckle switch and ground.
- CHECK SEAT BELT BUCKLE SWITCH (PASSENGER SIDE)
Check seat belt buckle switch (passenger side). Refer to "COMPONENT INSPECTION (BELT BUCKLE SWITCH) ".
Is the inspection result normal?
YES: Replace pre-crash seat belt control unit (passenger side).
NO: Replace seat belt buckle switch (passenger side).
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.