Inspection Procedure

For circuit wiring diagram, see Fig 1.

1. Check that DTC 42 is not output. If the result is OK, go to the next step. If the result is not OK, check the RDA line. See DTC B1242/42: WIRELESS DOOR LOCK TUNER CIRCUIT under DIAGNOSTIC TESTS under MULTIPLEX COMMUNICATION SYSTEM article in COMMUNICATION DEVICES.
2. Check the wiring harness. Disconnect the connectors of the wireless door lock tuner and B5 of the body ECU No. 1. Check the continuity between terminals RCO of the wireless door lock tuner and RCO of the body ECU No. 1. If there is continuity, go to the next step. If there is not continuity, repair or replace the wiring harness.
3. Check the wireless door lock tuner. Replace the wireless door lock tuner with a known-good unit and check if system operates normally. If the wireless door lock tuner system operates normally, replace original wireless door lock tuner. If the results are not OK, reinstall original wireless door lock tuner and go to KEY UNLOCK WARNING SWITCH CIRCUIT  diagnosis.

Fig 1: Wireless Door Lock Tuner Circuit Wiring Diagram

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