DTC C2179-79: Tire Pressure Monitor ECU Communication Stop [03/2017 - 09/2019]: Procedure

1. Using an oscilloscope, check the waveform.
   NOTE:

   With the connector connected, check from the backside of the connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Main Body ECU (Multiplex Network Body ECU))
   *b	GND

   OK

   Tester Connection	Tool Setting Range	Condition	Specified Condition
   K53-11 (PRG) - Body ground	5 V/DIV.5 ms./DIV.	Ignition switch ON	Waveform generation

   Result

   Result	Proceed to
   Waveform is as shown in the illustration. (Waveform alternates between 9.8 V or higher and 1.2 V or less)	A
   Waveform does not change from 9.8 V or higher	B
   Waveform does not change from 1.2 V or less	C

Result: 

A 

REPLACE TIRE PRESSURE WARNING ECU AND RECEIVER. Refer to  REMOVAL [03/2017 - 06/2017]  , or refer to  REMOVAL [06/2017 - 09/2019] 

Result: 

B 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [03/2017 - 06/2017]  , or refer to  REMOVAL [06/2017 - 10/2020] 

Result: 

C 

See step  2

1. Disconnect the K53 main body ECU (multiplex network body ECU) connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   K53-11 (PRG) - Body ground	Ignition switch ON	9.8 V or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [03/2017 - 06/2017]  , or refer to  REMOVAL [06/2017 - 10/2020] 

Result: 

NG 

See step  3

1. Turn the ignition switch off.
2. Disconnect the R9 or R120 tire pressure warning ECU and receiver connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   W/ SMART KEY SYSTEM
   
   

   Tester Connection	Condition	Specified Condition
   R9-5 (PRG) - K53-11 (PRG)	Always	Below 1 Ω
   R9-5 (PRG) or K53-11 (PRG) - Body ground	Always	10 kΩ or higher

   W/O SMART KEY SYSTEM
   
   

   Tester Connection	Condition	Specified Condition
   R120-5 (PRG) - K53-11 (PRG)	Always	Below 1 Ω
   R120-5 (PRG) or K53-11 (PRG) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

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

   Standard Voltage

   W/ SMART KEY SYSTEM
   
   

   Tester Connection	Condition	Specified Condition
   R9-7 (+B) - Body ground	Always	10 to 16 V
   R9-1 (IG) - Body ground	Ignition switch ON	10 to 16 V

   W/O SMART KEY SYSTEM
   
   

   Tester Connection	Condition	Specified Condition
   R120-7 (+B) - Body ground	Always	10 to 16 V
   R120-1 (IG) - Body ground	Ignition switch ON	10 to 16 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE TIRE PRESSURE WARNING ECU AND RECEIVER. Refer to  REMOVAL [03/2017 - 06/2017]  , or refer to  REMOVAL [06/2017 - 09/2019] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR