DTC U1177-87: Lost Communication with Side Obstacle Detection Control Module "A" (ch2) Missing Message; DTC U1178-87: Lost Communication with Side Obstacle Detection Control Module "B" (ch2) Missing Message [10/2020 - 10/2023]: Procedure
- CHECK FOR DTC
- Check for DTCs.
Refer to DTC CHECK / CLEAR [10/2020 - ]
Body Electrical > Clearance Warning > Trouble Codes
- Clear the DTCs.
Refer to DTC CHECK / CLEAR [10/2020 - ]
Body Electrical > Clearance Warning > Clear DTCs
- Recheck for DTCs.
Refer to DTC CHECK / CLEAR [10/2020 - ]
Body Electrical > Clearance Warning > Trouble Codes
Result
Result Proceed to No DTCs are output A DTC U1177-87 only is output B DTC U1178-87 only is output C DTC U1177-87 and U1178-87 are output D
Result:
A
USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2020 - 11/2021] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 10/2022] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - 10/2023]
Result:
C
See step 5
Result:
D
See step 8
Result:
B
See step 2
- Check for DTCs.
- CHECK HARNESS AND CONNECTOR (BLIND SPOT MONITOR SENSOR LH (A) - BATTERY AND BODY GROUND)
- Disconnect the blind spot monitor sensor LH (A) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L57-10 (BLGD) - Body ground Always Below 1 Ω - Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Switch Condition Specified Condition L57-5 (BLB) - Body ground Engine switch on (IG) 11 to 14 V L57-5 (BLB) - Body ground Engine switch off Below 1 V Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 3
- CHECK FOR OPEN IN CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR LH [A])
- Disconnect the cable from the negative (-) battery terminal.
- Disconnect the blind spot monitor sensor LH (A) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L57-1 (CA2P) - L57-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Proceed to OK NG
Result:
OK
REPLACE BLIND SPOT MONITOR SENSOR LH (A). Refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
See step 4
- CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 20 CAN JUNCTION CONNECTOR)
- Reconnect the blind spot monitor sensor LH (A) connector.
- Disconnect the No. 20 CAN junction connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L124-2 (CANH) - L124-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Proceed to OK NG
Result:
OK
REPLACE NO. 20 CAN JUNCTION CONNECTOR
Result:
NG
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH [A] - NO. 20 CAN JUNCTION CONNECTOR)
- CHECK HARNESS AND CONNECTOR (BLIND SPOT MONITOR SENSOR RH (B) - BATTERY AND BODY GROUND)
- Disconnect the blind spot monitor sensor RH (B) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L56-10 (BRGD) - Body ground Always Below 1 Ω - Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Switch Condition Specified Condition L56-5 (BRB) - Body ground Engine switch on (IG) 11 to 14 V L56-5 (BRB) - Body ground Engine switch off Below 1 V Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 6
- CHECK FOR OPEN IN CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR RH [B])
- Disconnect the cable from the negative (-) battery terminal.
- Disconnect the blind spot monitor sensor RH (B) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L56-1 (CA2P) - L56-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Proceed to OK NG
Result:
OK
REPLACE BLIND SPOT MONITOR SENSOR RH (B). Refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
See step 7
- CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 20 CAN JUNCTION CONNECTOR)
- Reconnect the blind spot monitor sensor RH (B) connector.
- Disconnect the No. 20 CAN junction connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L124-3 (CANH) - L124-14 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Proceed to OK NG
Result:
OK
REPLACE NO. 20 CAN JUNCTION CONNECTOR
Result:
NG
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH [B] - NO. 20 CAN JUNCTION CONNECTOR)
- CHECK CAN BUS MAIN WIRE
- Disconnect the cable from the negative (-) battery terminal.
- Disconnect the clearance warning ECU connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition Result L18-37 (CANH) - L18-38 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Below 54 Ω: Short circuit between bus lines 70 Ω or more: Open circuit in main bus lines L18-37 (CANH) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANH short to ground L18-38 (CANL) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANL short to ground L18-37 (CANH) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short L18-38 (CANL) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: CANL +B short Result
Result Proceed to OK A Open circuit in CAN bus lines B Short circuit between bus lines C - Short to ground
- +B short
D
Result:
A
REPLACE CLEARANCE WARNING ECU ASSEMBLY. Refer to REMOVAL [12/2017 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
C
See step 13
Result:
D
See step 17
Result:
B
See step 9
- CHECK FOR OPEN IN CAN BUS WIRE (NO. 20 JUNCTION CONNECTOR)
- Disconnect the No. 20 CAN junction connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L124-2 (CANH) - L124-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω L124-3 (CANH) - L124-14 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Result Proceed to OK A NG (to blind spot monitor sensor LH (A) CAN main wire) B NG (to blind spot monitor sensor RH (B) CAN main wire) C
Result:
B
See step 11
Result:
C
See step 12
Result:
A
See step 10
- CHECK FOR OPEN IN CAN BUS WIRE (NO. 20 JUNCTION CONNECTOR)
- Reconnect the No. 20 CAN junction connector.
*a Rear view of wire harness connector
(to No. 20 CAN Junction Connector)*b to Clearance Warning ECU Assembly CAN Wire - Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L124-1 (CANH) - L124-12 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Result
Proceed to OK NG
Result:
OK
REPAIR OR REPLACE CAN BUS WIRE (CLEARANCE WARNING ECU ASSEMBLY - NO. 20 CAN JUNCTION CONNECTOR)
Result:
NG
REPLACE NO. 20 CAN JUNCTION CONNECTOR
- Reconnect the No. 20 CAN junction connector.
- CHECK FOR OPEN IN CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR LH (A))
- Reconnect the L124 No. 20 CAN junction connector.
- Disconnect the blind spot monitor sensor LH (A) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L57-1 (CA2P) - L57-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Proceed to OK NG
Result:
OK
REPLACE BLIND SPOT MONITOR SENSOR LH (A). Refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH (A) - NO. 20 CAN JUNCTION CONNECTOR)
- CHECK FOR OPEN IN CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR RH (B))
- Reconnect the L124 No. 20 CAN junction connector.
- Disconnect the blind spot monitor sensor RH (B) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L56-1 (CA2P) - L56-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Proceed to OK NG
Result:
OK
REPLACE BLIND SPOT MONITOR SENSOR RH (B). Refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH (B) - NO. 20 CAN JUNCTION CONNECTOR)
- CHECK FOR SHORT IN CAN BUS WIRES (NO. 20 JUNCTION CONNECTOR)
- Disconnect the No. 20 CAN junction connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L124-1 (CANH) - L124-12 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher L124-2 (CANH) - L124-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω L124-3 (CANH) - L124-14 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Result Proceed to OK A NG (to blind spot monitor sensor LH (A) CAN main wire) B NG (to blind spot monitor sensor RH (B) CAN main wire) C NG (to clearance warning ECU assembly CAN wire) D
Result:
A
REPLACE NO. 20 CAN JUNCTION CONNECTOR
Result:
C
See step 15
Result:
D
See step 16
Result:
B
See step 14
- CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR LH (A))
- Reconnect the L124 No. 20 CAN junction connector.
- Disconnect the blind spot monitor sensor LH (A) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L57-1 (CA2P) - L57-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Proceed to OK NG
Result:
OK
REPLACE BLIND SPOT MONITOR SENSOR LH (A). Refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH (A) - NO. 20 JUNCTION CONNECTOR)
- CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR RH (B))
- Reconnect the L124 No. 20 CAN junction connector.
- Disconnect the blind spot monitor sensor RH (B) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L56-1 (CA2P) - L56-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Result
Proceed to OK NG
Result:
OK
REPLACE BLIND SPOT MONITOR SENSOR RH (B). Refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH (B) - NO. 20 JUNCTION CONNECTOR)
- CHECK FOR SHORT IN CAN BUS WIRES (CLEARANCE WARNING ECU ASSEMBLY)
- Reconnect the L124 No. 20 CAN junction connector.
- Disconnect the clearance warning ECU connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L18-37 (CANH) - L18-38 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Result
Proceed to OK NG
Result:
OK
REPLACE CLEARANCE WARNING ECU ASSEMBLY. Refer to REMOVAL [12/2017 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
REPAIR OR REPLACE CAN BUS WIRE (CLEARANCE WARNING ECU ASSEMBLY - NO. 20 JUNCTION CONNECTOR)
- CHECK FOR SHORT IN CAN BUS WIRES (NO. 20 JUNCTION CONNECTOR)
- Disconnect the No. 20 junction connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L124-1 (CANH) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L124-12 (CANL) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L124-1 (CANH) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher L124-12 (CANL) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher L124-2 (CANH) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L124-13 (CANL) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L124-2 (CANH) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher L124-13 (CANL) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher L124-3 (CANH) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L124-14 (CANL) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L124-3 (CANH) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher L124-14 (CANL) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher HINT:
Check for short that was confirmed to be a malfunction by confirming symptoms.
Result
Result Proceed to OK A NG (to blind spot monitor sensor LH (A) CAN main wire) B NG (to blind spot monitor sensor RH (B) CAN main wire) C NG (to clearance warning ECU assembly CAN wire) D
Result:
A
REPLACE NO. 20 CAN JUNCTION CONNECTOR
Result:
C
See step 19
Result:
D
See step 20
Result:
B
See step 18
- CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR LH (A))
- Reconnect the L124 No. 20 CAN junction connector.
- Disconnect the blind spot monitor sensor LH (A) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L57-1 (CA2P) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L57-6 (CA2N) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L57-1 (CA2P) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher L57-6 (CA2N) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Result
Proceed to OK NG
Result:
OK
REPLACE BLIND SPOT MONITOR SENSOR LH (A). Refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH (A) - NO. 20 JUNCTION CONNECTOR)
- CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR RH (B))
- Reconnect the L124 No. 20 CAN junction connector.
- Disconnect the blind spot monitor sensor RH (B) connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L56-1 (CA2P) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L56-6 (CA2N) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L56-1 (CA2P) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher L56-6 (CA2N) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Result
Proceed to OK NG
Result:
OK
REPLACE BLIND SPOT MONITOR SENSOR RH (B). Refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH (B) - NO. 20 JUNCTION CONNECTOR)
- CHECK FOR SHORT IN CAN BUS WIRES (CLEARANCE WARNING ECU ASSEMBLY)
- Reconnect the L124 No. 20 CAN junction connector.
- Disconnect the clearance warning ECU connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L18-37 (CANH) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L18-38 (CANL) - G112-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher L18-37 (CANH) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher L18-38 (CANL) - G112-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Result
Proceed to OK NG
Result:
OK
REPLACE CLEARANCE WARNING ECU ASSEMBLY. Refer to REMOVAL [12/2017 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]
Result:
NG
REPAIR OR REPLACE CAN BUS WIRE (CLEARANCE WARNING ECU ASSEMBLY - NO. 20 JUNCTION CONNECTOR)