ECU Power Source Circuit

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

DESCRIPTION

This circuit provides power to operate the driving support ECU. The driving support ECU determines information about the vehicle in front based on data from the radar sensor, and then decides how much acceleration and/or deceleration is needed to maintain the set distance. The driving support ECU also requests the skid control ECU to apply braking and to sound the buzzer.

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.





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

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

Standard Voltage:





(d) Reconnect the driving support ECU connector.

NG -- INSPECT IG1 RELAY
OK -- Continue to next step.

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

(a) Disconnect the driving support ECU connector.





Text in Illustration





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

Standard Resistance (Check for Open):





(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 IG1 RELAY

(a) Remove the IG1 relay from the engine room relay block.





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

Standard Resistance:





(c) Reinstall the IG1 relay.

NG -- REPLACE IG1 RELAY
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU - IG1 RELAY)

(a) Disconnect the driving support ECU connector.





Text in Illustration





(b) Remove the IG1 relay from the engine room relay block.

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

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Install the IG1 relay.

(e) Reconnect the driving support ECU connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVING SUPPORT ECU - IG1 RELAY)
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (IG1 RELAY POWER SOURCE CIRCUIT)

(a) Disconnect the IG1 relay from the engine room relay block.





Text in Illustration





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

Standard Voltage:





(c) Reconnect the IG1 relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 RELAY - BATTERY)
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (IG1 RELAY - BODY GROUND)

(a) Disconnect the IG1 relay from the engine room relay block.





Text in Illustration





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

Standard Resistance (Check for Open):





(c) Reconnect the IG1 relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 RELAY - BODY GROUND)
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - IG1 RELAY)

(a) Disconnect the power management control ECU connector.





Text in Illustration





(b) Remove the IG1 relay from the engine room relay block.

(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) Reinstall the IG1 relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - IG1 RELAY)

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