DTC U0235: Lost Communication with Cruise Control Front Distance Range Sensor; DTC U1104: Lost Communication with Driving Support ECU [11/2017 - 09/2020]: Procedure

1. Using the Techstream, check if the CAN communication system is functioning normally.

   Refer to DIAGNOSIS SYSTEM [11/2017 - 10/2018] , or refer to DIAGNOSIS SYSTEM [10/2018 - 11/2019] , or refer to DIAGNOSIS SYSTEM [11/2019 - 09/2020]

   Result

   Result	Proceed to
   CAN communication system DTCs are not output	OK
   CAN communication system DTCs are output	NG

Result: 

NG 

GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2017 - 10/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2018 - ] 

Result: 

OK 

See step  2

1. Disconnect the Q2 driving support ECU assembly connector.
2. Measure the voltage and resistance according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   Q2-7 (B) - Body ground	Engine switch on (IG)	11 to 14 V
   Q2-7 (B) - Body ground	Engine switch off	Below 1 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Q2-28 (GND) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Disconnect the B9 millimeter wave radar sensor assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Millimeter Wave Radar Sensor Assembly)

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   B9-8 (IGB) - Body ground	Engine switch on (IG)	11 to 14 V
   B9-8 (IGB) - Body ground	Engine switch off	Below 1 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   B9-1 (SGND) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Disconnect the Q2 driving support ECU assembly connector.
2. Disconnect the B9 millimeter wave radar sensor assembly connector.
3. Disconnect the W17 forward recognition camera connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Q2-8 (CA1P) - B9-5 (CA1P)	Always	Below 1 Ω
   Q2-9 (CA1N) - B9-6 (CA1N)	Always	Below 1 Ω
   Q2-8 (CA1P) or B9-5 (CA1P) - Body ground	Always	10 kΩ or higher
   Q2-9 (CA1N) or B9-6 (CA1N) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Replace the millimeter wave radar sensor assembly with a new one.

   Refer to REMOVAL [11/2017 - 10/2022]

2. Perform millimeter wave radar sensor assembly adjustment.

   Refer to ADJUSTMENT [11/2017 - 10/2022]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  6

1. Clear the DTCs.

   Powertrain > Radar Cruise > Clear DTCs 

2. Perform the following to make sure that the DTC detection conditions are met.

   HINT: 

   If the following conditions are not met, the system cannot detect the malfunction.

   1. Turn the engine switch on (IG).
   2. Turn the dynamic radar cruise control system on using the cruise control main switch (ON/OFF button).
   3. Drive the vehicle at 36 km/h (22 mph) or more for 1 second or more.
3. Check for DTCs.

   Powertrain > Radar Cruise > Trouble Codes 

   Result

   Result	Proceed to
   DTC U0235 and U1104 are not output	A
   DTC U0235 or U1104 is output	B

Result: 

A 

END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE) 

Result: 

B 

REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  COMPONENTS [09/2014 - 10/2022]