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CAN Communication System (Diagnostic Codes & Symptom Tests): Overview Lexus CT I

Communication Devices 28 illustrations ~1122 words

DESCRIPTION

DTC No.DTC Detection ConditionTrouble Area
U0100No communication from the ECM continues.ECM main line or connector Power source circuit of ECM ECM

HINT

This diagnosis procedure is for when DTC U0100 is output by the power management control ECU (Techstream display: PM2 Gateway).

Scheme 107

Scheme 107: WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
U0104No communication from the driving support ECU continues.Driving support ECU assembly branch line or connector Power source circuit of driving support ECU assembly Driving support ECU assembly

HINT

This diagnosis procedure is for when DTC U0104 is output by the power management control ECU (Techstream display: PM1 Gateway).

Scheme 108

Scheme 108: WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
U0129No communication from the skid control ECU continues.Skid control ECU branch line or connector Power source circuit of skid control ECU Skid control ECU (Brake booster with master cylinder assembly)

HINT

This diagnosis procedure is for when DTC U0129 is output by the power management control ECU (Techstream display: PM2 Gateway).

Scheme 109

Scheme 109: WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
U0164No communication from the air conditioning amplifier assembly continues.Air conditioning amplifier assembly branch line or connector Power source circuit of air conditioning amplifier assembly Air conditioning amplifier assembly

HINT

This diagnosis procedure is for when DTC U0164 is output by the power management control ECU (Techstream display: PM2 Gateway).

Scheme 110

Scheme 110: WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
U0199No communication from the outer mirror control ECU assembly continues.Outer mirror control ECU assembly (Front passenger side) branch line or connector Power source circuit of outer mirror control ECU assembly (Front passenger side) Outer mirror control ECU assembly (Front passenger side)

HINT

This diagnosis procedure is for when DTC U0199 is output by the main body ECU (Techstream display: Main Body).

Scheme 111

Scheme 111: WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
U0200No communication from the outer mirror control ECU assembly continues.Outer mirror control ECU assembly (Driver side) branch line or connector Power source circuit of outer mirror control ECU assembly (Driver side) Outer mirror control ECU assembly (Driver side)

HINT

This diagnosis procedure is for when DTC U0200 is output by the main body ECU (Techstream display: Main Body).

Scheme 112

Scheme 112: WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
U0208No communication from the position control ECU and switch assembly continues.Position control ECU and switch assembly branch line or connector Power source circuit of position control ECU and switch assembly Position control ECU and switch assembly

HINT

This diagnosis procedure is for when DTC U0208 is output by the main body ECU (Techstream display: Main Body).

Scheme 113

Scheme 113: WIRING DIAGRAM
  1. The main body ECU will store this DTC when no signals can be received from the ECUs that have been memorized as those that are connected to the CAN MS bus.
  2. When the main body ECU receives a response signal from the ECUs connected to the CAN MS bus, the main body ECU recognizes and memorizes that the ECU is connected to the CAN MS bus. Based on this memorized data, the main body ECU monitors for malfunctions in the ECUs connected to the CAN MS bus when communicating with those ECUs. If the main body ECU cannot receive response signals from the ECUs that have been memorized as those connected to the CAN MS bus, the main body ECU determines that a malfunction exists.
DTC No.DTC Detection ConditionTrouble Area
U1002Main body ECU cannot receive signals from all ECUs that have been memorized as those connected to the CAN MS bus.Open or short in CAN MS bus main line or connector Open or short in CAN MS bus branch line or connector Main body ECU (Multiplex network body ECU) Outer mirror control ECU assembly (Driver side) Outer mirror control ECU (Front passenger side) Position control ECU and switch assembly CAN No. 6 junction connector

HINT

This diagnosis procedure is for when DTC U1002 is output by the main body ECU (Techstream display: Main Body).

Scheme 114

Scheme 114: WIRING DIAGRAM
  1. The power management control ECU will store this DTC when no signals can be received from the ECUs that have been memorized as those that are connected to the V2 bus.
  2. When the power management control ECU receives a response signal from the ECUs connected to the V2 bus, the power management control ECU recognizes and memorizes that the ECU is connected to the V2 bus. Based on this memorized data, the power management control ECU monitors for malfunctions in the ECUs connected to the V2 bus when communicating with those ECUs. If the power management control ECU cannot receive response signals from the ECUs that have been memorized as those connected to the V2 bus, the power management control ECU determines that a malfunction exists.
DTC No.DTC Detection ConditionTrouble Area
U1002Power management control ECU cannot receive signals from all ECUs that have been memorized as those connected to the V2 bus.Open or short in V2 bus main line or connector Open or short in V2 bus branch line or connector Power management control ECU Driving support ECU assembly Seat belt control ECU Parking assist ECU Clearance warning ECU assembly CAN No. 4 junction connector

HINT

This diagnosis procedure is for when DTC U1002 is output by the power management control ECU (Techstream display: PM1 Gateway).

Scheme 115

Scheme 115: WIRING DIAGRAM
  1. The power management control ECU will store this DTC when no signals can be received from the ECUs that have been memorized as those that are connected to the power management bus.
  2. When the power management control ECU receives a response signal from the ECUs connected to the power management bus, the power management control ECU recognizes and memorizes that the ECU is connected to the power management bus. Based on this memorized data, the power management control ECU monitors for malfunctions in the ECUs connected to the power management bus when communicating with those ECUs. If the power management control ECU cannot receive response signals from the ECUs that have been memorized as those connected to the power management bus, the power management control ECU determines that a malfunction exists.
DTC No.DTC Detection ConditionTrouble Area
U1002Power management control ECU cannot receive signals from all ECUs that have been memorized as those connected to the power management bus.Open or short in power management bus main line or connector Open or short in power management bus branch line or connector Power management control ECU ECM Air conditioning amplifier assembly Skid control ECU (Brake booster with master cylinder assembly) CAN No. 1 junction connector CAN No. 5 junction connector

HINT

This diagnosis procedure is for when DTC U1002 is output by the power management control ECU (Techstream display: PM2 Gateway).

Scheme 116

Scheme 116: WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
U1100No communication from the seat belt control ECU continues.Seat belt control ECU branch line or connector Power source circuit of seat belt control ECU Seat belt control ECU

HINT

This diagnosis procedure is for when DTC U1100 is output by the power management control ECU (Techstream display: PM1 Gateway).

Scheme 117

Scheme 117: WIRING DIAGRAM
DTC No.DTC Detection ConditionTrouble Area
U110BNo communication from the parking assist ECU continues.Parking assist ECU branch line or connector Power source circuit of parking assist ECU Parking assist ECU

HINT

This diagnosis procedure is for when DTC U110B is output by the power management control ECU (Techstream display: PM1 Gateway).

Scheme 118

Scheme 118: WIRING DIAGRAM
DTC CodeDTC Detection ConditionTrouble Area
U1110No communication from clearance warning ECU assemblyClearance warning ECU assembly branch line or connector Power source circuit of clearance warning ECU assembly Clearance warning ECU assembly

HINT

This diagnosis procedure is for when DTC U1110 is output by the power management control ECU (Techstream display: PM1 Gateway).

Scheme 119

Scheme 119: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Skid Control ECU Communication Stop Mode"ABS/VSC/TRAC" is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Skid Control ECU Communication Stop Mode in DTC Combination Table.Skid control ECU branch line or connector Power source circuit of Skid control ECU Skid control ECU (Brake booster with master cylinder assembly)

Scheme 120

Scheme 120: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Power Steering ECU Communication Stop Mode"EPS" is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Power Steering ECU Communication Stop Mode in DTC Combination Table.Power steering ECU assembly branch line or connector Power source circuit of power steering ECU assembly Power steering ECU assembly

Scheme 121

Scheme 121: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Steering Angle Sensor Communication Stop Mode"Steering Angle Sensor" is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Steering Angle Sensor Communication Stop Mode in DTC Combination Table.Steering angle sensor branch line or connector Power source circuit of steering angle sensor Steering angle sensor (Spiral cable with sensor sub-assembly)

Scheme 122

Scheme 122: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Yaw Rate Sensor Communication Stop Mode"Yaw Rate/Decelerate Sensor" is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Yaw Rate Sensor Communication Stop Mode in DTC Combination Table.Yaw rate and acceleration sensor branch line or connector Power source circuit of yaw rate and acceleration sensor Yaw rate and acceleration sensor

Scheme 123

Scheme 123: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
ECM Communication Stop Mode"Engine" are not displayed on the "CAN Bus Check" screen of the Techstream. Applies to ECM Communication Stop Mode in DTC Combination Table.Power source circuit of ECM ECM main line or connector ECM

Scheme 124

Scheme 124: WIRING DIAGRAM

The transmission control ECU drives the parking lock actuator in accordance with signals from the power management control ECU.

Detection ItemSymptomTrouble Area
Transmission Control ECU Communication Stop Mode"Transmission Control " is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Transmission Control ECU Communication Stop Mode in DTC Combination Table.Transmission control ECU assembly branch line or connector Power source circuit of transmission control ECU assembly Transmission control ECU assembly

Scheme 125

Scheme 125: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Main Body ECU Communication Stop Mode"Main Body" is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Main Body ECU Communication Stop Mode in DTC Combination Table.Main body ECU branch line or connector Power source circuit of Main body ECU Main body ECU (Multiplex network body ECU)

Scheme 126

Scheme 126: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Power Management Control ECU Communication Stop Mode"Hybrid Control" and/or "Power Management 1" is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Power Management Control ECU Communication Stop Mode in DTC Combination Table.Power management control ECU branch line or connector Power source circuit of power management control ECU Power management control ECU

Scheme 127

Scheme 127: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Combination Meter ECU Communication Stop Mode"Combination Meter" is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Combination Meter ECU Communication Stop Mode in DTC Combination Table.Combination meter assembly main line or connector Power source circuit of combination meter assembly Combination meter assembly

Scheme 128

Scheme 128: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Certification ECU Communication Stop Mode"Smart Access/Smart Key/Wireless Tuner" is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Certification ECU Communication Stop Mode in DTC Combination Table.Certification ECU branch line or connector Power source circuit of Certification ECU Certification ECU (Smart key ECU assembly)

Scheme 129

Scheme 129: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Center Airbag Sensor Communication Stop Mode"SRS Airbag" is not displayed on the "CAN Bus Check" screen of the Techstream. Applies to Center Airbag Sensor Communication Stop Mode in DTC Combination Table.Airbag sensor assembly branch line or connector Power source circuit of airbag sensor assembly Airbag sensor assembly

Scheme 130

Scheme 130: WIRING DIAGRAM
Detection ItemSymptomTrouble Area
Navigation ECU Communication Stop Mode"AVN1" is not displayed on the "CAN Bus Check" screen of the Techstream Applies to Navigation ECU Communication Stop Mode in DTC Combination TableNavigation ECU branch line or connector Power source circuit of Navigation ECU Navigation ECU (Display and navigation module display)*1 Navigation ECU (Navigation computer sub-assembly)*2
  1. *1: w/ Navigation System (for DVD)
  2. *2: w/ Navigation System (for HDD)

Scheme 131

Scheme 131: WIRING DIAGRAM

There may be an open circuit one of the CAN V1 bus main lines and/or a DLC3 branch line when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is 70 ohms or higher.

SymptomTrouble Area
Resistance between terminals 6 (CANH) and 14 (CANL) of DLC3 is 70 ohms or higher.DLC3 branch line or connector CAN main bus line or connector ECM Combination meter assembly CAN No. 1 junction connector CAN No. 2 junction connector CAN No. 3 junction connector

Scheme 132

Scheme 132: WIRING DIAGRAM

There may be a short circuit between the V1 bus main lines and/or CAN branch lines when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 ohms.

SymptomTrouble Area
Resistance between terminals 6 (CANH) and 14 (CANL) of DLC3 is below 54 ohms.Short in CAN main bus line Short in CAN branch line Power management control ECU ECM Main body ECU (Multiplex network body ECU) Combination meter assembly Skid control ECU (Brake booster with master cylinder assembly) Steering angle sensor (Spiral cable with sensor sub-assembly) Yaw rate and acceleration sensor Power steering ECU assembly Airbag sensor assembly Transmission control ECU assembly Certification ECU (Smart key ECU assembly) Navigation ECU (Display and navigation module display)*1 Navigation ECU (Navigation computer sub-assembly)*2 CAN No. 1 junction connector CAN No. 2 junction connector CAN No. 3 junction connector

*1: w/ Navigation system (for DVD)

*2: w/ Navigation system (for HDD)

Scheme 133

Scheme 133: WIRING DIAGRAM

Scheme 134

Scheme 134

There may be a short circuit between one of the CAN bus lines and +B when no resistance exists between terminals 6 (CANH) and 16 (BAT) or 14 (CANL) and 16 (BAT) of the DLC3.

SymptomTrouble Area
No resistance exists between terminals 6 (CANH) and 16 (BAT) or 14 (CANL) and 16 (BAT) of DLC3.Short to +B in CAN main bus line Short to +B in CAN branch line Power management control ECU ECM Main body ECU (Multiplex network body ECU) Combination meter assembly Skid control ECU (Brake booster with master cylinder assembly) Steering angle sensor (Spiral cable with sensor sub-assembly) Yaw rate and acceleration sensor Power steering ECU assembly Airbag sensor assembly Transmission control ECU assembly Certification ECU (Smart key ECU assembly) Navigation ECU (Display and navigation module display)*1 Navigation ECU (Navigation computer sub-assembly)*2 CAN No. 1 junction connector CAN No. 2 junction connector CAN No. 3 junction connector

*1: w/ Navigation system (for DVD)

*2: w/ Navigation system (for HDD)

There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of the DLC3.

SymptomTrouble Area
No resistance exists between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of DLC3.Short to ground in CAN main bus line Short to ground in CAN branch line Power management control ECU ECM Main body ECU (Multiplex network body ECU) Combination meter assembly Skid control ECU (Brake booster with master cylinder assembly) Steering angle sensor (Spiral cable with sensor sub-assembly) Yaw rate and acceleration sensor Power steering ECU assembly Airbag sensor assembly Transmission control ECU assembly Certification ECU (Smart key ECU assembly) Navigation ECU (Display and navigation module display)*1 Navigation ECU (Navigation computer sub-assembly)*2 CAN No. 1 junction connector CAN No. 2 junction connector CAN No. 3 junction connector

*1: w/ Navigation system (for DVD)

*2: w/ Navigation system (for HDD)

If an ECU or sensor is not displayed on the "CAN Bus Check" screen of the Techstream and some ECUs and sensors repeatedly appear and disappear from the screen when the CAN main bus lines are normal (there is no open, short, short to B+ or short to GND in the main bus lines), there may be an open circuit in either of one pair of CAN branch lines.

HINT

If some ECUs and sensors repeatedly appear and disappear from the "CAN Bus Check" screen, communication between the normal ECUs (sensors) and the Techstream may be affected by the incomplete signals that are output from the ECU that has an open circuit in either of its CAN branch lines. In this case, the CAN branch lines for the ECUs and sensors that repeatedly appear and disappear from the screen are normal and the ECU that is not displayed on the screen may be the main cause of the problem (this ECU may have an open circuit in either of its CAN branch lines).

SymptomTrouble Area
2 or more ECUs and/or sensors do not appear on the Techstream "CAN Bus Check" screen.One side of CAN branch line is open, or output signals are incomplete. Power management control ECU ECM Main body ECU (Multiplex network body ECU) Combination meter assembly Skid control ECU (Brake booster with master cylinder assembly) Steering angle sensor (Spiral cable with sensor sub-assembly) Yaw rate and acceleration sensor Power steering ECU assembly Airbag sensor assembly Transmission control ECU assembly Certification ECU (Smart key ECU assembly) Navigation ECU (Display and navigation module display)*1 Navigation ECU (Navigation computer sub-assembly)*2

*1: w/ Navigation system (for DVD)

*2: w/ Navigation system (for HDD)

See also:
REMOVAL
REMOVAL
REMOVAL
REMOVAL
REMOVAL