Page 1383 of 1500
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-52
STEP 4. Using Diagnostic Tool MB991958, read the
auto-cruise control system 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) Use Diagnostic Tool MB991958 to read the auto-cruise
control system diagnostic trouble codes. (Refer to P.17-11).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect Diagnostic Tool MB991958.
Q: Is DTC 1574 set?
YES : Return to Step 1.
NO : The procedure is complete.
Page 1384 of 1500

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-53
SYMPTOM CHARTM1172002300366
NOTE: If engine speed reaches and exceeds 6000
r/min the Auto Cruise Control System will be can-
celled automatically.SYMPTOM INSPECTION
PROCEDURE NO.REFERENCE
PA G E
Communication with
Diagnostic Tool is
not possibleCommunication with all systems is
impossible- Group 13A, MPI
Diagnosis
Symptom
Procedures
Inspection
Procedure 1
13A-539 .
Communication with the Engine ECU only
is impossible- Group 13A, MPI
Diagnosis
Symptom
Procedures
Inspection
Procedure 2
13A-541 .
Auto-cruise control
system is not
cancelled.When brake pedal is depressed 1
P.17-54
When selector lever is moved to "N" range 2
P.17-54
When "CANCEL" switch is turned ON 3
P.17-55
When clutch pedal is depressed 4
P.17-55
Auto-cruise control system cannot be set. 5
P.17-56
Hunting (repeated acceleration and deceleration) occurs at the
set vehicle speed.6
P.17-60
When "CRUISE" (MAIN) switch is turned "ON", "CRUISE"
indicator lamp inside combination meter does not illuminate.
(However, auto-cruise control system is normal).7
P.17-62
Page 1385 of 1500

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-54
SYMPTOM PROCEDURES
INSPECTION PROCEDURE 1: When the Brake Pedal is Depressed, Auto-cruise Control System is not
Cancelled.
.
COMMENT
The stoplamp switch circuit is suspected.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the stoplamp switch.
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
Refer to P.17-35, Diagnostic Trouble Code Procedures DTC
22: Stoplamp Switch System.
INSPECTION PROCEDURE 2: When the Selector Lever is Moved to "N" Range, Auto-cruise Control
System is not Cancelled.
.
COMMENT
The transmission inhibitor switch circuit is suspected.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the transmission inhibitor switch.
Damaged harness or connector.
Malfunction of the Engine ECU.
Malfunction of A/T ECU.
Circuit drawings
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Refer to component locations GROUP-70
DIAGNOSIS
Refer to GROUP 23A, A/T Diagnosis Diagnostic Trouble
Code Procedures
DTC 0705: Transmission Inhibitor Switch
System (Open/short Circuit) P.23A-97.
Page 1386 of 1500

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-55
INSPECTION PROCEDURE 3: When the Auto-cruise Control "CANCEL" Switch is Set to ON,
Auto-cruise Control System is not Cancelled.
.
COMMENT
The cause is probably an open-circuit in the output in
the circuit inside the "CANCEL" switch.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the auto-cruise control switch.
Circuit drawings
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Refer to component locations GROUP-70
DIAGNOSIS
Replace the auto-cruise control switch. (Refer to P.17-75,
Auto-cruise Control).
INSPECTION PROCEDURE 4: When the Clutch Pedal is Depressed, Auto-cruise Control System is not
Cancelled.
.
COMMENT
The clutch switch circuit is suspected.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the clutch switch.
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
Refer to P.17-15, Diagnostic Trouble Code Procedures DTC
0830: Clutch Switch System.
Page 1387 of 1500

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-56
INSPECTION PROCEDURE 5: Auto-cruise Control System cannot be Set.
.
COMMENT
The fail-safe function is probably canceling
auto-cruise control system. In this case, Diagnostic
Tool MB991958 can be used to retest each system
by checking the diagnostic trouble codes. The
Diagnostic Tool can also be used to check if the cir-
cuits of each input switch are normal or not by check-
ing the input switch codes.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CASE:)
Malfunction of the auto-cruise control switch.
Malfunction of the stoplamp switch.
Malfunction of the transmission inhibitor switch.
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, 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 auto-cruise control system diagnostic trouble
code. (Refer to P.17-11).
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect Diagnostic Tool MB991958.
Q: Is DTC set?
YES : Diagnose the auto-cruise control system. (Refer to
P.17-14, Diagnostic Trouble Code Chart). Then go to
St e p 6 .
NO : Go to Step 2.
Page 1388 of 1500

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-57
STEP 2. Using Diagnostic Tool MB991958, check data list
item 75: Cancel Switch.
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) Set Diagnostic ToolDiagnostic Tool MB991958 to data
reading mode for auto-cruise control system. (Refer to
P.17-11).
Item 75, Cancel Switch.
When "CANCEL" switch is at the ON position, the
display on Diagnostic Tool MB991958 should be
"ON".
When "CANCEL" switch is at the OFF position, the
display on Diagnostic Tool MB991958 should be
"OFF".
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect Diagnostic Tool MB991958.
Q: Is the switch operating properly?
YES : Go to Step 3.
NO : Refer to P.17-55, Symptom Procedures
Inspection
Procedure 3. Then go to Step 6.
Page 1389 of 1500

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-58
STEP 3. Using Diagnostic ToolDiagnostic Tool MB991958,
check data list item 74: Stoplamp Switch and data list item
89: Brake switch.
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) Set Diagnostic Tool MB991958 to data reading mode for
auto-cruise control system. (Refer to P.17-11).
Item 74, Stoplamp Switch.
When brake pedal is depressed, the display on
Diagnostic Tool MB991958 should be "ON".
When brake pedal is released, the display on
Diagnostic Tool MB991958 should be "OFF".
Item 89, Brake Switch.
When brake pedal is depressed, the display on
Diagnostic Tool MB991958 should be "ON".
When brake pedal is released, the display on
Diagnostic Tool MB991958 should be "OFF".
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect Diagnostic Tool MB991958.
Q: Is the switch operating properly?
YES : Go to Step 4.
NO : Refer to P.17-54, Symptom Procedures
Inspection
Procedure 1. Then go to Step 6.
Page 1390 of 1500

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-59
STEP 4. Using Diagnostic Tool MB991958, check A/T data
list item 34: Transmission Inhibitor Switch.
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) Set Diagnostic Tool MB991958 to data reading mode for
Auto Transmission system. (Refer to P.17-11).
Item 34, Transmission Inhibitor Switch.
When selector lever is at the "P" or "N" position, the
display on Diagnostic Tool MB991958 should be
"ON".
When selector lever is at the "R" or "D" position, the
display on Diagnostic Tool MB991958 should be
"OFF".
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect Diagnostic Tool MB991958.
Q: Is the switch operating properly?
YES : Go to Step 5.
NO : Refer to P.17-54, Symptom Procedures
Inspection
Procedure 2. Then go to Step 6.
STEP 5. Check the symptoms.
Q: Can auto-cruise control be set?
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 6.
STEP 6. Check the symptoms.
Q: Can auto-cruise control be set?
YES : The procedure is complete.
NO : Return to Step 1.