Page 1391 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-60
INSPECTION PROCEDURE 6: Hunting (Repeated Acceleration and Deceleration) Occurs at the Set
Vehicle Speed.
.
COMMENT
The output shaft speed sensor signal or the throttle
body is suspected.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the output shaft speed sensor.
Malfunction of the throttle body.
Malfunction of the Engine ECU.
Malfunction of the A/T ECU.
Circuit drawings
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Refer to component locations GROUP-70
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.17-11).
(2) Turn the ignition switch to the "ON" position.
(3) Check for A/T system diagnostic trouble code. (Refer to
GROUP 23A, A/T Diagnosis
Diagnostic Function How
to Read and Erase Diagnostic Trouble Code P.23A-13).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect Diagnostic Tool MB991958.
Q: Is any DTC set?
YES : Diagnose the A/T system. (Refer to GROUP 23A, A/T
Diagnosis
Diagnostic Trouble Code Chart
P.23A-34). Then go to Step 4.
NO : Go to Step 2.
Page 1392 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-61
STEP 2. 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.17-11).
(2) Turn the ignition switch to the "ON" position.
(3) Check for MPI system diagnostic trouble code(Refer to
GROUP 13A, MPI Diagnosis
Diagnostic Function How
to Read and Erase Diagnostic Trouble Code 13A-6).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect Diagnostic Tool MB991958.
Q: Is any DTC set?
YES : Diagnose the MPI system. (Refer to GROUP 13A,
MPI Diagnosis
Diagnostic Trouble Code Chart
13A-17). Then go to Step 4.
NO : Go to Step 3.
STEP 3. Retest the system
Q: Does hunting occur?
YES : Replace the Engine ECU[Refer to GROUP 13A,
Engine ECU 13A-675]. Then go to Step 4.
NO : 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).
STEP 4. Retest the system
Q: Does hunting occur?
YES : Return to Step 1.
NO : The procedure is complete.
Page 1393 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-62
INSPECTION PROCEDURE 7: When "CRUISE" (MAIN) Switch is Turned "ON", "CRUISE" Indicator
Light Inside Combination Meter does not Illuminate. (However, Auto-cruise Control System is
Normal).
.
Page 1394 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-63
CIRCUIT OPERATION
The Engine ECU detects "CRUISE" (MAIN) switch
"ON" signal to illuminate the "CRUISE" indicator
lamp on the combination meter.
.
COMMENT
Connector(s), wiring harness in the CAN bus line
between the Engine ECU and the combination
meter, power supply to the Engine ECU, the combi-
nation meter, the Engine ECU may be defective.
.
TROUBLESHOOTING HINTS
Malfunction of the combination meter.
Damaged harness or connector.
Malfunction of the Engine ECU.
Circuit drawings
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Refer to component locations GROUP-70
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, diagnose the
CAN bus line.
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.17-11).
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line. (Refer to P.17-11).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect Diagnostic Tool MB991958.
Q: Is the check result satisfactory?
YES : Go to Step 2
NO : Repair the CAN bus lines. (Refer to GROUP 54C,
Diagnosis
Can Bus Diagnostic Chart P.54C-15).
Then go to Step 4.
Page 1395 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-64
STEP 2. Using Diagnostic Tool MB991958, read the MPI
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.17-11).
(2) Turn the ignition switch to the "ON" position.
(3) Check for MPI system diagnostic trouble code(Refer to
GROUP 13A, MPI Diagnosis
Diagnostic Function How
to Read and Erase Diagnostic Trouble Code 13A-6).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect Diagnostic Tool MB991958.
Q: Is DTC U1108 set?
YES : . Then go to Step 4.
NO : Go to Step 3.
STEP 3. Retest the system.
Q: Does the "CRUISE" indicator lamp illuminate when the
"CRUISE" (MAIN) switch is turned "ON"?
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 Engine ECU. [Refer to GROUP 13A,
Engine ECU 13A-675]. Then go to Step 4.
STEP 4. Retest the system.
Q: Does the "CRUISE" indicator lamp illuminate when the
"CRUISE" (MAIN) switch is turned "ON"?
YES : The procedure is complete.
NO : Return to Step 1.
Page 1396 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-65
DATA LIST REFERENCE TABLE - Auto Cruise ControlM1172002400471
When shifting the selector lever to "D" range, apply the brakes so that the vehicle does not move
forward.
Driving tests always need two persons: one driver and one observer.
NOTE: *:After the inspection is completed, disconnect the throttle position sensor connector, and then delete
the diagnostic trouble code using use of Diagnostic Tool MB991958. (Refer to P.17-11).
MUT-III
Diagnostic
To o l
DISPLAYITEM
NO.INSPECTION ITEM INSPECTION REQUIREMENT NORMAL
CONDITION
APS
SNS(MAIN)11 A c c e l e r a t o r p e d a l
position sensor (main)Ignition
switch:
"ON"Accelerator pedal: Released
435
1,035 mV
Accelerator pedal: Gradually
depressedIncreases in
response to the
pedal depression
stroke
Accelerator pedal: Fully
depressed4,000 mV or more
BRAKE SW 89 Stoplamp switch Brake pedal: Depressed ON
Brake pedal: Released OFF
CANCEL
CODE57 Cancel code Ignition switch: "ON" The cancel code,
which set when the
auto-cruise control
system was
cancelled at the
last time, is set
again.
CANCEL
SWITCH75 Auto-cruise
control
switchCANCEL "CANCEL" switch: ON ON
"CANCEL" switch: OFF OFF
CLUTCH SW 78 Transmission inhibitor
switchTransmission inhibitor switch: "P" or
"N"ON
Transmission inhibitor switch: Other
than aboveOFF
CRUISE 81 Auto-cruise control
system operationAuto-cruise control system: active ON
Auto-cruise control system: Inactive OFF
MAIN SW 86 Auto-cruise
control
switchCRUISE
(MAIN)"CRUISE" (MAIN) switch: "ON" ON
"CRUISE" (MAIN) switch: "OFF" OFF
RESUME
SWITCH91 Auto-cruise
control
switchACC/RES "ACC/RES" switch: ON ON
"ACC/RES" switch: OFF OFF
SET SWITCH 92 Auto-cruise
control
switchCOAST/S
ET"COAST/SET" switch: ON ON
"COAST/SET" switch: OFF OFF
STOPLIGHT
SW74 Stoplamp switch Brake pedal: Depressed ON
Brake pedal: Released OFF
Page 1397 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-66
If the air intake duct is removed from the throttle body take great care to keep fingers away
from the throttle plate. The drive motor has very high torque and is capable of random move-
ment at any time. Do not under any circumstances activate the throttle plate by hand.
When removing the throttle body from the intake manifold disconnect the wiring first. During
replacement connect the wiring last.
Do not activate the throttle body using a DC suppy to test the motor,as permanent damage to
the throttle body will result.
TP
SNSR(MAIN)13 Throttle position sensor
(main)*(1) Accelerator pedal:
Released
(2) Accelerator pedal:
Depressed(1) Throttle
valve fully
closed1035 1250 mV
(2) Throttle
valve fully
open4,000 mV or more
A/C switch: "OFF" to "ON" Voltage rises
Selector lever: "N" to "D" Voltage rises
VSS 04 Vehicle speed signal Road test the vehicle The speedometer
and Diagnostic
Tool MB991958
display the same
value. MUT-III
Diagnostic
To o l
DISPLAYITEM
NO.INSPECTION ITEM INSPECTION REQUIREMENT NORMAL
CONDITION
Page 1398 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-67
ENGINE ECU TERMINAL VOLTAGE REFERENCE CHART FOR AUTO-CRUISE
CONTROL SYSTEM OPERATION
M1172004800055
1. Disconnect the Engine ECU connectors B-20,
B-21, and connect special tool MB992044
(ENGINE ECU check harness) in between.2. Measure the voltages between the check
connector terminals of special tool MB992044 and
ground connector B-21 terminals 4 or 6.
TERMINAL
NO.CHECK ITEM CHECK CONDITION NORMAL
CONDITION
18 (B-21) Stoplamp switch Ignition
switch:
"ON"Depress the brake pedal. Battery positive
voltage
Release the brake pedal. 1V or less
14 (B-21) Auto-cruise control
switch power supplyIgnition
switch:
"ON"All switches: OFF 4.7
5.0 V
"CRUISE" (MAIN) switch: "ON" 0
0.3 V
"COAST/SET" switch: ON 2.0
2.8 V
"ACC/RES" switch: ON 3.3
4.1 V
"CANCEL" switch: ON 0.8
1.5 V
76 (B-21) Accelerator pedal
position sensor (sub)
power supplyIgnition switch: "ON" 4.9
5.1 V
59 (B-21) Accelerator pedal
position sensor
(main)Ignition
switch:
"ON"Release the accelerator pedal
0.435
1.035 V
Depress the accelerator pedal. 4.0 V or more
81 (B-21) Accelerator pedal
position sensor (sub)Ignition
switch:
"ON"Release the accelerator pedal
0.435
1.035 V
Depress the accelerator pedal. 4.0 V or more
75 (B-21) Accelerator pedal
position sensor
(main) power supplyIgnition switch: "ON" 4.9
5.1 V
21 (B-21) Brake switch Ignition
switch:
"ON"Depress the brake pedal. 1V or less
Release the brake pedal. 1V or less
9 (B-20) Transmission inhibitor
switch: "P" and "N"
Crank switch signalIgnition
switch:
"ON"Transmission inhibitor switch: "P" or
"N" Crank switch signalBattery positive
voltage
Transmission inhibitor switch: Other
than above1V or less
