Inspection Procedure

WARNING: This page is about a different car, the 2002 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Before ECU replacement, see HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS to ensure all communication line/bus/wire issues have been eliminated as a cause of communication loss.

Check wire harness.
Preparation : Disconnect the connector of tuner and body ECU.

Check Continuity between wire harness and body ground.

OK : No continuity

Fig 1: Testing RDA continuity
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1. NG : Repair or replace the wire harness.
2. OK : Go to next step.
Check body ECU.
Preparation : Connect the connector of body ECU.

Check the DTC.

OK : B1242/42 is not output.

Fig 2: Connecting Body ECU To RDA
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Replace the body ECU.
2. OK : Replace the tuner.