
TRACTION CONTROL SYSTEM (TCL) DIAGNOSIS
TRACTION CONTROL SYSTEM (TCL)13C-10
NOTE: Since the TCL is controlled with the same ABS/TCL-ECU used to control the ABS, the codes (with a 
*) used only for the ABS also appear.
The inspection contents for the codes (with a *) used only for the ABS do not described in this group.
DIAGNOSTIC TROUBLE CODE PROCEDURES
U1100 CAN Communications System Time Out Error Engine Related Data
If DTC U1100 is set in the ABS/TCL-ECU, 
always diagnose the CAN main bus line. If 
there is any fault in the CAN bus lines, an 
incorrect DTC may be set.
Whenever the ABS/TCL-ECU is replaced, 
ensure that the communication circuit is nor-
mal.
NOTE: If the ABS-8 ECU or the active wheel 
speed sensor are disconnected, or if the wiring is 
an open/ short circuit, the ABS 8 ECU will shut 
off power supply to the respective wheel speed 
sensor. All other wheel speed sensors will oper-
ate normally. To restore the power supply, the 
ignition switch must be turned to the "OFF" posi-
tion then to the "ON" position again.
.
DTC SET CONDITION
The ABS/TCL-ECU receives engine system-related 
signals from the ENGINE-ECU via CAN bus lines.
.
TROUBLESHOOTING HINTS (THE MOST 
LIKELY CAUSES FOR THESE DTCS ARE 
TO SET ARE:)
Damaged harness or connector.
Malfunction of the ENGINE-ECU.
Malfunction of the ABS/TCL-ECU.
DIAGNOSIS
Required Special Tools:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A U1073 CAN communications system bus off GROUP 35B, ABS 
Diagnosis 
 
Diagnostic Trouble 
Code Procedures 
U1073 P.35B-68
U1100 CAN communications system time out error engine related data
P.13C-10
U1101 CAN communications system time out error A/T related data
P.13C-14
U1400 Dynamic range error APS1
P.13C-22
U1415 CAN invalid signal Gear Position GROUP 23A    
Diagnostic Trouble 
Code Chart P.23A-34 DTC INSPECTION ITEM DIAGNOSTIC CONTENT REFERENCE PAGE 

TRACTION CONTROL SYSTEM (TCL) DIAGNOSIS
TRACTION CONTROL SYSTEM (TCL)13C-14
STEP 6. Using diagnostic tool MB991958, read the 
diagnostic trouble code.
To prevent damage to diagnostic tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting diagnostic tool 
MB991958.
(1) Connect diagnostic tool MB991958 to the data link 
connector. (Refer to P.13C-3).
(2) Turn the ignition switch to the "ON" position.
(3) Use diagnostic tool MB991958 to read the TCL diagnostic 
trouble codes. (Refer to P.13C-3).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect diagnostic tool MB991958.
Q: Is DTC U1100 set?
YES : Return to Step 1.
NO : The procedure is complete.
U1101 CAN Communications System Time Out Error A/T Related Data
If DTC U1101 is set in the ABS/TCL-ECU, 
always diagnose the CAN main bus line. If 
there is any fault in the CAN bus lines, an 
incorrect DTC may be set.
Whenever the ABS/TCL-ECU is replaced, 
ensure that the communication circuit is nor-
mal.
NOTE: If the ABS-8 ECU or the active wheel 
speed sensor are disconnected, or if the wiring is 
an open/ short circuit, the ABS 8 ECU will shut 
off power supply to the respective wheel speed 
sensor. All other wheel speed sensors will oper-
ate normally. To restore the power supply, the 
ignition switch must be turned to the "OFF" posi-
tion then to the "ON" position again.
.
DTC SET CONDITION
The ABS/TCL-ECU receives A/T system-related sig-
nals from the A/T-ECU via CAN bus lines.
.
TROUBLESHOOTING HINTS (THE MOST 
LIKELY CAUSES FOR THESE DTCS ARE 
TO SET ARE:)
Damaged harness or connector.
Malfunction of the A/T-ECU.
Malfunction of the ABS/TCL-ECU.
DIAGNOSIS
Required Special Tools:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A 

TRACTION CONTROL SYSTEM (TCL) DIAGNOSIS
TRACTION CONTROL SYSTEM (TCL)13C-18
STEP 6. Using diagnostic tool MB991958, read the 
diagnostic trouble code.
To prevent damage to diagnostic tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting diagnostic tool 
MB991958.
(1) Connect diagnostic tool MB991958 to the data link 
connector. (Refer to P.13C-3).
(2) Turn the ignition switch to the "ON" position.
(3) Use diagnostic tool MB991958 to read the TCL diagnostic 
trouble codes. (Refer to P.13C-3).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect diagnostic tool MB991958.
Q: Is DTC U1101 set?
YES : Return to Step 1.
NO : The procedure is complete.
U1120 CAN Communications System TCL Uncontrollable by Engine Malfunction
If DTC U1120 is set in the ABS/TCL-ECU, 
always diagnose the CAN main bus line. If 
there is any fault in the CAN bus lines, an 
incorrect DTC may be set.
Whenever the ABS/TCL-ECU is replaced, 
ensure that the communication circuit is nor-
mal.
The engine control system-related DTC may 
be set when DTC U1120 is set. (For details 
refer to GROUP 00, Intersystem Affiliated DTC 
Reference Table P.00-17). Diagnose the 
engine control system first when the engine 
control system-related DTC is set.
NOTE: If the ABS-8 ECU or the active wheel 
speed sensor are disconnected, or if the wiring is 
an open/ short circuit, the ABS 8 ECU will shut 
off power supply to the respective wheel speed 
sensor. All other wheel speed sensors will oper-
ate normally. To restore the power supply, the 
ignition switch must be turned to the "OFF" posi-
tion then to the "ON" position again.
.
DTC SET CONDITION
The ABS/TCL-ECU receives engine system-related 
signals from the Engine-ECU via CAN bus lines. If a 
fail-safe related data is contained in the signal from 
the Engine-ECU, DTC U1120 will be stored.
.
TROUBLESHOOTING HINTS (THE MOST 
LIKELY CAUSES FOR THESE DTCS ARE 
TO SET ARE:)
Damaged harness or connector.
Malfunction of the Engine-ECU.
Malfunction of the ABS/TCL-ECU. 

TRACTION CONTROL SYSTEM (TCL) DIAGNOSIS
TRACTION CONTROL SYSTEM (TCL)13C-25
NOTE: If you press the TCL switch to deactivate the 
TCL and then keep the TCL switch pressed for about 
10 seconds, an error prevention function will auto-
matically reactivate the TCL. If you then still wish to 
deactivate the TCL, press the TCL switch again to 
deactivate it.NOTE: If the ABS-8 ECU or the active wheel 
speed sensor are disconnected, or if the wiring is 
an open/ short circuit, the ABS 8 ECU will shut 
off power supply to the respective wheel speed 
sensor. All other wheel speed sensors will oper-
ate normally. To restore the power supply, the 
ignition switch must be turned to the "OFF" posi-
tion then to the "ON" position again.
. 

TRACTION CONTROL SYSTEM (TCL) DIAGNOSIS
TRACTION CONTROL SYSTEM (TCL)13C-28
STEP 4. Retest the system
Q: Turn the ignition switch to the "ON" position. Do the 
"TCL OFF" indicator light and the TCL work indicator 
light illuminate for three seconds, and then go out after 
the engine starts?
YES : The procedure is complete.
NO : . Return to Step 1.
INSPECTION PROCEDURE 5: When the TCL Switch is Pushed On, TCL does not Cancel.
NOTE: If the ABS-8 ECU or the active wheel 
speed sensor are disconnected, or if the wiring is 
an open/ short circuit, the ABS 8 ECU will shut 
off power supply to the respective wheel speed 
sensor. All other wheel speed sensors will oper-
ate normally. To restore the power supply, the 
ignition switch must be turned to the "OFF" posi-
tion then to the "ON" position again.
.
CIRCUIT OPERATION
ABS/TCL-ECU terminal 21 is grounded every time 
the TCL switch is pressed. ABS/TCL-ECU monitors 
this operation state and turns the TCL ON or OFF.
.
COMMENT
The cause is probably an open-circuit in the TCL 
switch circuit.
.
TROUBLESHOOTING HINTS
Malfunction of the TCL switch.
Damaged harness or connector.
Malfunction of the ABS/TCL-ECU.
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
MB991219: Inspection Test Harness 

TRACTION CONTROL SYSTEM (TCL) DIAGNOSIS
TRACTION CONTROL SYSTEM (TCL)13C-34
INSPECTION PROCEDURE 6: TCL does not Operate.
NOTE: If the ABS-8 ECU or the active wheel 
speed sensor are disconnected, or if the wiring is 
an open/ short circuit, the ABS 8 ECU will shut 
off power supply to the respective wheel speed 
sensor. All other wheel speed sensors will oper-
ate normally. To restore the power supply, the 
ignition switch must be turned to the "OFF" posi-
tion then to the "ON" position again.
.
COMMENT
The fail-safe function is probably cancelling TCL. In 
this case, diagnostic tool MB991958 can be used to 
retest each system by checking the diagnostic trou-
ble codes.
.
TROUBLESHOOTING HINTS (THE MOST 
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the CAN bus line.
Malfunction of the MPI system.
Malfunction of the A/T system.
Malfunction of the ABS/TCL-ECU.
DIAGNOSIS
Required Special Tools:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
STEP 1. Using diagnostic tool MB991958, read the 
diagnostic trouble code.
To prevent damage to diagnostic tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting diagnostic tool 
MB991958.
(1) Connect diagnostic tool MB991958 to the data link 
connector. (Refer to P.13C-3).
(2) Turn the ignition switch to the "ON" position.
(3) Use diagnostic tool MB991958 to read the TCL diagnostic 
trouble codes. (Refer to P.13C-3).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect diagnostic tool MB991958.
Q: Is any DTC set?
YES : Repair the TCL. (Refer to P.13C-8, Diagnostic 
Trouble Code Chart). Then go to Step 4.
NO : Go to Step 2. 

TRACTION CONTROL SYSTEM (TCL) DIAGNOSIS
TRACTION CONTROL SYSTEM (TCL)13C-35
STEP 2. Using diagnostic tool MB991958, check TCL 
actuator test item09: Engine TCL Drive.
To prevent damage to diagnostic tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting diagnostic tool 
MB991958.
(1) Connect diagnostic tool MB991958 to the data link 
connector. (Refer to P.13C-3).
(2) Turn the ignition switch to the "ON" position.
The engine speed increases after the actuator test 
because the actuator test continues for only three sec-
onds. Therefore, release the accelerator pedal immedi-
ately. 
(3) Use diagnostic tool MB991958 to check the actuator test. 
(Refer to P.13C-3).
Item 09: Engine TCL Drive.
When the accelerator pedal is depressed at the 
same time that the button for actuator test item 09 
displayed on diagnostic tool MB991958 is pressed, 
the system prevents the engine speed from rising for 
three seconds.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect diagnostic tool MB991958.
Q: Are the check results for actuator test item 09 
satisfactory?
YES : Go to Step 3.
NO : Replace the hydraulic unit (integrated with 
ABS/TCL-ECU). (Refer to GROUP 35B 
 Hydraulic 
Unit P.35B-93). Then go to Step 4.
STEP 3. Retest the system
Q: Does the TCL work normally?
YES : It can be assumed that this malfunction is intermittent. 
(Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 
 How to 
Cope with Intermittent Malfunction P.00-14).
NO : Replace the hydraulic unit (integrated with 
ABS/TCL-ECU). (Refer to GROUP 35B 
 Hydraulic 
Unit P.35B-93). Then go to Step 4.
STEP 4. Retest the system
Q: Does the TCL work normally?
YES : The procedure is complete.
NO : Return to Step 1. 

TRACTION CONTROL SYSTEM (TCL) DIAGNOSIS
TRACTION CONTROL SYSTEM (TCL)13C-36
DATA LIST REFERENCE TABLEM1136003500071
NOTE: If the ABS-8 ECU or the active wheel 
speed sensor are disconnected, or if the wiring is 
an open/ short circuit, the ABS 8 ECU will shut 
off power supply to the respective wheel speed 
sensor. All other wheel speed sensors will oper-
ate normally. To restore the power supply, the 
ignition switch must be turned to the "OFF" posi-
tion then to the "ON" position again.The following items can be read by the diagnostic 
tool from the ABS/TCL-ECU input data. (Refer to 
P.13C-3).
NOTE: Since the TCL is controlled with the same ABS/TCL-ECU used to control the ABS, the stoplight switch 
check item (No.6) used only for the ABS also appear.MUT-III 
DIAGNOSTI
C TOOL 
DISPLAYITEM 
NO.CHECK ITEM CHECKING REQUIREMENTS NORMAL 
VA L U E
FL wheel 
speed sensor01 Front left wheel speed sensor Drive the vehicle Vehicle speeds 
displayed on the 
speedometer 
and diagnostic 
tool are identical. FR wheel 
speed sensor02 Front right wheel speed sensor
RL wheel 
speed sensor03 Rear left wheel speed sensor
RR wheel 
speed sensor04 Rear right left wheel speed 
sensor
Power supply 
voltage05 ABS/TCL-ECU power supply 
voltageIgnition switch power supply 
voltageBattery positive 
voltage
Stoplamp 
switch 
(input)*06 Stoplamp switch Depress the brake pedal. ON
Release the brake pedal. OFF
Stoplamp 
switch*13 Stoplamp switch Depress the brake pedal. ON
Release the brake pedal. OFF
Pump motor 21 Pump motor When the ABS outputs the 
operation permission signal 
during drivingON
When the ABS outputs the 
operation permission signal 
during drivingOFF
Valve relay 30 Valve relayWhen the ABS outputs the 
operation permission signal 
during drivingON
When the ABS outputs the 
operation permission signal 
during drivingOFF
TCL mode 35 TCL operation When the TCL outputs the 
operation permission signal 
during drivingON
When the TCL outputs the 
operation inhibition signal 
during drivingOFF