ECU Power Source Circuit

CRUISE CONTROL: DYNAMIC RADAR CRUISE CONTROL SYSTEM: ECU Power Source Circuit
- ECU Power Source Circuit

DESCRIPTION

* The driving support ECU assembly controls the cruise control system based on information sent from switches, sensors and ECUs.

* The power management control ECU sends current to the IG1 No. 1 relay. This closes the contact points in the relay so that power is supplied to the driving support ECU +B terminal.

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. CHECK DRIVING SUPPORT ECU (B VOLTAGE)

(a) Disconnect the driving support ECU connector.





(b) Turn the power switch on (IG).

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





(d) Reconnect the driving support ECU connector.

NG -- INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU - BODY GROUND)

(a) Disconnect the driving support ECU connector.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):





Text in Illustration





(c) Reconnect the driving support ECU connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVING SUPPORT ECU - BODY GROUND)

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Dynamic Radar Cruise Control System

3. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Remove the instrument panel junction block assembly.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





(c) Reinstall the instrument panel junction block assembly.

NG -- REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU - INSTRUMENT PANEL JUNCTION BLOCK)

(a) Disconnect the driving support ECU connector.

(b) Disconnect the instrument panel junction block assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):





Standard Resistance (Check for Shorts):





(d) Reconnect the instrument panel junction block assembly connector.

(e) Reconnect the driving support ECU connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVING SUPPORT ECU - INSTRUMENT PANEL JUNCTION BLOCK)
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK POWER SOURCE CIRCUIT)

(a) Disconnect the instrument panel junction block assembly connector.





(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





(c) Reconnect the instrument panel junction block assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BATTERY)
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BODY GROUND)

(a) Disconnect the instrument panel junction block assembly connector.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





(c) Reconnect the instrument panel junction block assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BODY GROUND)
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - INSTRUMENT PANEL J/B ASSEMBLY)

(a) Disconnect the power management control ECU connector.

(b) Disconnect the instrument panel junction block assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Reconnect the power management control ECU connector.

(e) Reconnect the instrument panel junction block assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - INSTRUMENT PANEL J/B ASSEMBLY)

OK -- GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START How To Proceed With Troubleshooting