DTC C2179: Tire Pressure Monitor ECU Communication Stop [12/2019 - 11/2023]: 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
   H44-11 (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 [12/2019 - 11/2023] 

Result: 

B 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

Result: 

C 

See step  2

1. Disconnect the H44 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
   H44-11 (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 [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

Result: 

NG 

See step  3

1. Turn the ignition switch off.
2. Disconnect the M51 tire pressure warning ECU and receiver connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   M51-5 (PRG) - H44-11 (PRG)	Always	Below 1 Ω
   M51-5 (PRG) or H44-11 (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

   Tester Connection	Condition	Specified Condition
   M51-7 (+B) - Body ground	Always	10 to 16 V
   M51-1 (IG) - Body ground	Ignition switch ON	10 to 16 V

   Result

   Result	Proceed to
   OK	A
   NG (w/ Stop and Start System)	B
   NG (w/o Stop and Start System)	C

Result: 

A 

REPLACE TIRE PRESSURE WARNING ECU AND RECEIVER. Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

B 

INSPECT STOP AND START SYSTEM (BACKUP BOOST CONVERTER CIRCUIT). Refer to  Backup Boost Converter Circuit [12/2019 - 10/2022]  , or refer to  Backup Boost Converter Circuit [10/2022 - 11/2023] 

Result: 

C 

REPAIR OR REPLACE HARNESS OR CONNECTOR