AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-18
STEP 4. Measure the power supply voltage at ENGINE-ECU
connector B-21 by using ENGINE-ECU check harness
special tool MB992044.
(1) Disconnect the all ENGINE-ECU connectors and connect
ENGINE-ECU check harness special tool MB992044
between the separated connectors.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal No. 41 and ground.
Voltage should be battery positive voltage.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts)
present?
YES : Repair or replace the open or damaged wiring circuit
between ENGINE-ECU connector B-21 and Clutch
switch connector C-07. Then go to Step 8.
NO : Check the connector B-21 for damage and ensure
check harness connection t ENGINE-ECU is correct.
If connection is correct and no power supply is
present at terminal 41 of ENGIN-ECU then replace it.
Then go to Step 7.
STEP 5. Measure the clutch switch power supply voltage
by backprobing the clutch switch connector C-07 (terminal
2).
(1) Measure the voltage between terminal No. 2 and ground by
backprobing. while depressing the clutch pedal.
When pedal is not depressed an (open circuit) , voltage
should be battery positive voltage.
When pedal is depressed an (closed circuit) , voltage
should be less than 1.0 volt.
Q: Is there battery voltage at terminal No. 2 when pedal is
depressed?
YES : Go to Step 6.
NO : Replace the Clutch switch. Refer to GROUP 21A,
Clutch - On-vehicle Service - Clutch Pedal Check and
Adjustment P.21A-2. Then go to Step 7.
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-22
STEP 1. Using Diagnostic Tool MB991958, check data list
item 86: Main Switch, list item 92: Set Switch, item 91:
Resume Switch and 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 Tool MB991958 to data reading mode for
auto-cruise control system. (Refer to P.17-11).
Item 86: Main Switch.
When "CRUISE" (MAIN) switch is at the "ON" posi-
tion, the display on Diagnostic Tool MB991958
should be "ON".
When ""CRUISE" (MAIN) switch is at the "OFF"
position, the display on Diagnostic Tool MB991958
should be "OFF".
Item 92: Set Switch.
When "COAST/SET" switch is at the "ON" position,
the display on Diagnostic Tool MB991958 should be
"ON".
When "COAST/SET" switch is at the "OFF" position,
the display on Diagnostic Tool MB991958 should be
"OFF".
Item 91: Resume Switch.
When "ACC/RES" switch is at the "ON" position, the
display on Diagnostic Tool MB991958 should be
"ON".
When "ACC/RES" switch is at the "OFF" position,
the display on Diagnostic Tool MB991958 should be
"OFF".
Item 75: Cancel Switch.
When "CANCEL" switch is at the "ON" position, the
display on Diagnostic Tool MB991958 should be
"ON".
When "ACC/RES" 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 17.
NO : Go to Step 2.
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-23
STEP 2. Measure the power supply voltage at auto-cruise
control switch connector C-302 by backprobing.
(1) Remove the air bag module (driver’s side). (Refer to
GROUP 52B, Air Bag Modules and Clock Spring
P.52B-237).
(2) Connect the negative (
) battery cable.
(3) Do not disconnect auto-cruise control switch connector
C-302.
(4) Turn the ignition switch to the "ON" position.
(5) The "CRUISE" (MAIN) switch to the "OFF" position.
(6) Measure the power supply voltage between auto-cruise
control switch connector C-302 terminal 2 and ground by
backprobing.
(7) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.7 and 5.0 volts?
YES : Go to Step 9.
NO : Go to Step 3.
STEP 3. Measure the power supply voltage at Engine ECU
connector B-21.
(1) Disconnect all the connectors from the Engine ECU.
(2) Connect special tool MB992044 between the Engine ECU
and the body-side harness connector.
(3) Turn the ignition switch to the "ON" position.
(4) The "CRUISE" (MAIN) switch to the "OFF" position.
(5) Measure the power supply voltage between special tool
94-pin connector terminal 14 (Engine ECU connector B-21
terminal 14) and ground.
(6) Turn the ignition switch to the "LOCK" (OFF) position.
(7) Disconnect special tool MB992044 between the Engine
ECU and the body-side harness connector.
(8) Reconnect all the connectors to the Engine ECU.
Q: Is the measured voltage between 4.7 and 5.0 volts?
YES : Go to Step 6.
NO : Go to Step 4.
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-24
STEP 4. Check Engine ECU connector B-21 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Are the connector and terminals in good condition?
YES : Go to Step 5.
NO : Repair the faulty connector if possible or as
recommended, replace complete wiring harness.
(Refer to GROUP 00E, Harness Connector Inspection
P.00E-2). Install the air bag module (driver’s side).
(Refer to GROUP 52B, Air Bag Modules and Clock
Spring P.52B-237). Then go to Step 18.
STEP 5. Check the harness for short circuit to ground
between the Engine ECU connector B-21 terminal 14 and
the auto-cruise control switch connector C-302 terminal 2.
(1) Disconnect Engine ECU connector B-21 and measure at
the harness connector side.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Measure the continuity between Engine ECU connector
B-21 terminal 14 and ground.
(4) Reconnect Engine ECU connector B-21.
Q: Is the measured continuity open circuit?
YES : Install the air bag module (driver’s side). (Refer to
GROUP 52B, Air Bag Modules and Clock Spring
P.52B-237). Then go to Step 17.
NO : Go to Step 6.
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-27
STEP 9. Measure the ground voltage at auto-cruise control
switch connector C-302 by backprobing.
(1) Do not disconnect auto-cruise control switch connector
C-302.
(2) Turn the ignition switch to the "ON" position.
(3) Turn the "CRUISE" (MAIN) switch to the "ON" position.
(4) Measure the ground voltage between auto-cruise control
switch connector C-302 terminal 3 and ground by
backprobing.
(5) Turn the "CRUISE" (MAIN) switch to the "OFF" position.
(6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage 0.5 volt or less?
YES : Go to Step 15.
NO : Go to Step 10.
STEP 10. Measure the ground voltage at Engine ECU
connector B-21.
(1) Disconnect all the connectors from the Engine ECU.
(2) Connect special tool MB992044 between the Engine ECU
and the body-side harness connector.
(3) Turn the ignition switch to the "ON" position.
(4) Turn the "CRUISE" (MAIN) switch to the "ON" position.
(5) Measure the ground voltage between special tool 94-pin
connector terminal 15 (Engine ECU connector B-21
terminal 15) and ground.
(6) Turn the "CRUISE" (MAIN) switch to the "OFF" position.
(7) Turn the ignition switch to the "LOCK" (OFF) position.
(8) Disconnect special tool MB992044 between the Engine
ECU and the body-side harness connector.
(9) Reconnect all the connectors to the Engine ECU.
Q: Is the measured voltage 0.5 volt or less?
YES : Go to Step 12.
NO : Go to Step 11.
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-32
STEP 16. Check the auto-cruise control switch.
(1) Remove auto-cruise control switch. (Refer to P.17-75).
(2) Measure the resistance between terminal 2 and terminal 3
when each of the "CRUISE" (MAIN), "COAST/SET",
"ACC/RES" and "CANCEL" switch is pressed.
Q: Is the resistance within specifications?
YES : Install the air bag module (driver’s side). (Refer to
GROUP 52B, Air Bag Modules and Clock Spring
P.52B-237). Then go to Step 17.
NO : Replace the auto-cruise control switch. (Refer to
P.17-75). Install the air bag module (driver’s side).
(Refer to GROUP 52B, Air Bag Modules and Clock
Spring P.52B-237). Then go to Step 18.
STEP 17. 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) Set Diagnostic Tool MB991958 to read the 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 1564 set?
YES : Replace the Engine ECU.[Refer to GROUP 13A,
Engine ECU 13A-675] . Then go to Step 18.
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). SWITCH POSITION SPECIFIED CONDITION
"CRUISE" (MAIN) switch
"OFF"Open circuit
"CRUISE" (MAIN) switch
"ON"Less than 2 ohms
"CANCEL" switch ON Approximately 100
"ACC/RES" switch ON Approximately 887
"COAST/SET" switch ON Approximately 300
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-33
STEP 18. 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) Set Diagnostic Tool MB991958 to read the 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 1564 set?
YES : Return to Step 1.
NO : The procedure is complete.
AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-36
DIAGNOSIS
Required Special Tools:
MB991958: Diagnostic ToolDiagnostic Tool (MUT-III Sub
Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
MB991223: Harness Set
MB992044: ENGINE-ECU Check Harness
STEP 1. Using Diagnostic Tool MB991958, check data list
item 74: Stoplamp 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 the brake pedal is depressed, the display on
Diagnostic Tool MB991958 should be "ON".
When the 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 14.
NO : Go to Step 2.
STEP 2. Check the stoplamp operation.
Check the stoplamp operation.
When the brake pedal is depressed, the stoplamp will
illuminate.
When the brake pedal is released, the stoplamp does
not illuminate.
Q: Does the stoplamp illuminate (when the brake pedal is
depressed) and the stoplamp does not illuminate (when
the brake pedal is released)?
YES : Go to Step 3.
NO : Go to Step 6.