OBDII Circuit Repairs

Repairs for On-Board Diagnostics II (OBDII) emission control circuits follow the procedures stated in Wire Repair Procedures. When servicing OBDII circuits, the following guidelines are also essential:
- Do not move or alter grounds from their manufactured locations.
- Do not tie aftermarket accessories into OBDII circuits.
- Only repair OBDII circuits in accordance with the manufactured configuration.
- Always replace a relay in an OBDII circuit the same replacement part. Damaged relays should he discarded, not repaired.
- Refer to Power and Ground Distribution to identify OBDII circuit fusing. Power and Ground Distribution
- Make sure that CPA (connector position assurance) locks and TPA (terminal position assurance) locks are reinstalled on connectors that use them.
- After repair of connectors or connector terminals, make sure to achieve proper terminal retention. Refer to Repairing Connectors for procedures.
- Before repairing OBDII heated oxygen sensors and related wiring, always review the special repair guidelines provided under Heated Oxygen Sensor (HO2S) Repair.
- When installing an electrical ground fastener, he sure to apply the specified torque. Ground torque specifications are listed in Power and Ground Distribution. Power and Ground Distribution
- After repair of connectors, make sure to reinstall connector seals, where used. Inspect seals for wear and damage. Replace worn or damaged seals.