C1379

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: C1379: Downhill Assist Control Switch Malfunction (Test Mode DTC)
C1379 - Downhill Assist Control Switch Malfunction (Test Mode DTC)

DESCRIPTION

w/ Downhill Assist Control:

DTC C1379 is cleared when the downhill assist control switch sends a downhill assist control operation signal or when test mode ends.

w/ Crawl Control:

DTC C1379 is cleared when the crawl control switch sends a crawl control operation signal or when test mode ends.





WIRING DIAGRAM









INSPECTION PROCEDURE

NOTICE:
* When replacing the master cylinder solenoid, perform calibration Programming and Relearning.
* Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. CONFIRM VEHICLE SPECIFICATIONS

(a) Confirm the vehicle specifications.

Result





B -- CHECK CAN BUS
A -- Continue to next step.

2. READ VALUE USING TECHSTREAM (DOWNHILL ASSIST CONTROL SW)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

(f) Check the Data List for proper functioning of the downhill assist control switch.

ABS/VSC/TRAC





OK:

The Techstream displays ON or OFF according to downhill assist control switch operation.

NG -- INSPECT DOWNHILL ASSIST CONTROL SWITCH
OK -- Continue to next step.

3. CHECK TEST MODE DTC

(a) Perform the Downhill Assist Control Switch Check in the Test Mode Procedure Test Mode Procedure.

OK:

Test mode DTC C1379 is cleared.

NG -- REPLACE MASTER CYLINDER SOLENOID Disassembly

OK -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting

4. INSPECT DOWNHILL ASSIST CONTROL SWITCH Downhill Assist Control Indicator Light does not Come ON

NG -- REPLACE DOWNHILL ASSIST CONTROL SWITCH Removal
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - DOWNHILL ASSIST CONTROL SWITCH/BODY GROUND)

(a) Disconnect the A6 skid control ECU connector.

(b) Disconnect the U4 downhill assist control switch connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE MASTER CYLINDER SOLENOID Disassembly

6. CHECK CAN BUS

(a) Check that there are no problems with the CAN communication system Diagnosis System.

NG -- GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) How to Proceed With Troubleshooting
OK -- Continue to next step.

7. READ VALUE USING TECHSTREAM (CRAWL CONTROL MODE SELECT SWITCH)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / D-SEAT SW / Data List.

(f) Check the Data List for proper functioning of the crawl control mode select switch.

D-SEAT SW





OK:

The Techstream displays ON or OFF according to crawl switch operation.

NG -- CHECK TERMINAL VOLTAGE AND RESISTANCE (IG, +B, GND)
OK -- Continue to next step.

8. READ VALUE USING TECHSTREAM (CRAWL CONTROL SWITCH)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

(f) Check the Data List for proper functioning of the crawl control switch.

ABS/VSC/TRAC





OK:

The Techstream displays LOW, MIDLOW, MID, MIDHIGH or HIGH according to crawl switch (mode selector switch) operation.

NG -- REPLACE DRIVE MONITOR SWITCH
OK -- Continue to next step.

9. CHECK TEST MODE DTC

(a) Perform the crawl switch check in the Test Mode Procedure Test Mode Procedure.

OK:

Test mode DTC C1379 is cleared.

NG -- REPLACE MASTER CYLINDER SOLENOID Disassembly

OK -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting

10. CHECK TERMINAL VOLTAGE AND RESISTANCE (IG, +B, GND)

(a) Disconnect the U1 drive monitor switch connector.

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





Standard Voltage:





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

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE DRIVE MONITOR SWITCH Removal

11. REPLACE DRIVE MONITOR SWITCH

(a) Replace the drive monitor switch Removal.

NEXT -- Continue to next step.

12. CHECK TEST MODE DTC

(a) Perform the crawl switch check in the Test Mode Procedure Test Mode Procedure.

OK:

Test mode DTC C1379 is cleared.

NG -- REPLACE MASTER CYLINDER SOLENOID Disassembly

OK -- END