DTC C1379: Downhill Assist Control Switch Malfunction (Test Mode DTC): Procedure

1. Confirm the vehicle specifications.
   RESULT
   
   

   Result	Proceed to
   w/ Downhill Assist Control	A
   w/ Crawl Control	B

B → See step   6 

A: Go to next step 

1. Turn the engine switch off.
2. Connect the Techstream to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the Techstream on.
5. Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.
6. Check the Data List for proper functioning of the downhill assist control switch.
   ABS/VSC/TRAC
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Downhill Assist Control SW	Downhill assist control switch / ON or OFF	ON: Downhill assist control on OFF: Downhill assist control off	-

   OK

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

NG → See step   4 

OK: Go to next step 

1. Perform the downhill assist control switch check in the Test Mode Procedure. Refer to TEST MODE PROCEDURE [06/2012 - ] .

   OK

   Test mode DTC C1379 is cleared.

NG → See step   11 

OK → See step   12 

NG → See step   13 

OK: Go to next step 

1. Disconnect the A7 skid control ECU connector.
2. Disconnect the i5 combination switch connector.
3. Measure the resistance according to the value(s) in the table below.
   STANDARD RESISTANCE
   
   

   Tester Connection	Condition	Specified Condition
   A7-44 (HDCS) - i5-15 (+B2)	Always	Below 1 Ω
   A7-44 (HDCS) - Body ground	Always	10 kΩ or higher
   i5-9 (E) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   11 

1. Check that there are no problems with the CAN communication system. Refer to DIAGNOSIS SYSTEM [06/2012 - ] .

NG → See step   14 

OK: Go to next step 

1. Turn the engine switch off.
2. Connect the Techstream to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the Techstream on.
5. Enter the following menus: Body Electrical / D-SEAT SW / Data List.
6. Check the Data List for proper functioning of the crawl control switch.
   D-SEAT SW
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Crawl Control Main Switch	Crawl control switch (ON/OFF switch)/ ON or OFF	ON: Crawl switch on OFF: Crawl switch off	-
   Crawl Control Up Switch	Crawl Control Switch (Speed selector switch)/ ON or OFF	ON: Speed selector switch pushed to the up side and held OFF: Speed selector switch not pushed to the up side	-
   Crawl Control Down Switch	Crawl Control Switch (Speed selector switch)/ ON or OFF	ON: Speed selector switch pushed to the down side and held OFF: Speed selector switch down side not pushed to the down side	-

   OK

   The Techstream displays according to crawl control switch operation.

NG → See step   9 

OK: Go to next step 

1. Perform the crawl control switch check in the Test Mode Procedure. Refer to TEST MODE PROCEDURE [06/2012 - ] .

   OK

   Test mode DTC C1379 is cleared.

NG → See step   11 

OK → See step   12 

1. Disconnect the i5 combination switch connector.
2. Disconnect the G60 driving support switch control ECU connector.
3. Measure the resistance according to the value(s) in the table below.
   STANDARD RESISTANCE
   
   

   Tester Connection	Condition	Specified Condition
   i5-6 (ECU) - G60-15 (SWI3)	Always	Below 1 Ω
   i5-6 (ECU) - Body ground	Always	10 kΩ or higher
   i5-5 (UP) - G60-13 (SWI4)	Always	Below 1 Ω
   i5-5 (UP) - Body ground	Always	10 kΩ or higher
   i5-3 (DN) - G60-14 (SWI5)	Always	Below 1 Ω
   i5-3 (DN) - Body ground	Always	10 kΩ or higher
   i5-9 (E) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the combination switch. Refer to REMOVAL [06/2012 - ] .
2. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   STANDARD RESISTANCE
   
   

   Tester Connection	Switch Condition	Specified Condition
   5 (UP) - 9 (E)	SPEED (UP): Pressed	Below 1 Ω
   	SPEED (UP): Not Pressed	10 kΩ or higher
   3 (DN) - 9 (E)	SPEED (DOWN): Pressed	Below 1 Ω
   	SPEED (DOWN): Not Pressed	10 kΩ or higher
   6 (ECU) - 9 (E)	ON/OFF: Pressed	Below 1 Ω
   	ON/OFF: Not pressed	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Speed Selector Switch
   *2	ON/OFF Switch
   *a	Component without harness connected (Crawl Control Switch [Combination Switch])

NG → See step   16 

OK → See step   15