DESCRIPTION
This circuit includes the navigation ECU and radio and display receiver assembly.
WIRING DIAGRAM
 
 PROCEDURE
| 1. | CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - NAVIGATION ECU) | 
(a) Disconnect the I153 radio receiver assembly connector.
(b) Disconnect the I173 navigation ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition | 
|---|---|---|
| I153-28 (REV2) - I173-19 (REV2) | Always | Below 1 Ω | 
| I153-28 (REV2) - Body ground | Always | 10 kΩ or higher | 
| OK | .gif)  |  PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE  | 
| NG | .gif)  | REPAIR OR REPLACE HARNESS OR CONNECTOR | 
 Start Up Signal Circuit between Radio Receiver Assembly and Navigation ECU
 Start Up Signal Circuit between Radio Receiver Assembly and Navigation ECU
	 Microphone Circuit
 Microphone Circuit
	 Visual Mute Signal Circuit between Radio Receiver and Multi-display
 Visual Mute Signal Circuit between Radio Receiver and Multi-display
	 Parts Location
 Parts Location
	 Brake Control Warning Light Remains ON
 Brake Control Warning Light Remains ON