Microphone Circuit between Microphone and Navigation Receiver Assembly [08/2017 - 08/2019]: Procedure

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Navigation Receiver Assembly)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H158-19 (MIN-) - Body ground	Always	Below 1 Ω

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   H158-4 (MACC) - Body ground	Ignition switch ACC	4.75 to 5.25 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE NAVIGATION RECEIVER ASSEMBLY. Refer to  REMOVAL [08/2015 - 08/2019] 

Result: 

OK 

See step  2

1. Disconnect the H158 navigation receiver assembly connector.
2. Disconnect the U7 roof console box assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H158-4 (MACC) - U7-10 (ACC)	Always	Below 1 Ω
   H158-5 (MIN+) - U7-9 (MIC+)	Always	Below 1 Ω
   H158-19 (MIN-) - U7-8 (MIC-)	Always	Below 1 Ω
   H158-6 (SNS2) - U7-14 (SGND)	Always	Below 1 Ω
   H158-4 (MACC) - Body ground	Always	10 kΩ or higher
   H158-5 (MIN+) - Body ground	Always	10 kΩ or higher
   H158-19 (MIN-) - Body ground	Always	10 kΩ or higher
   H158-18 (SGND) - Body ground	Always	10 kΩ or higher
   H158-6 (SNS2) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Replace the telephone microphone assembly with a known good.

   Refer to REMOVAL [08/2017 - 08/2019]

2. Check if the same problem occurs again.

   OK

   Malfunction disappears.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END (TELEPHONE MICROPHONE ASSEMBLY IS DEFECTIVE) 

Result: 

NG 

REPLACE ROOF CONSOLE BOX ASSEMBLY. Refer to  REMOVAL [08/2015 - 08/2019]