ECU MITSUBISHI 380 2005 Workshop Manual

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 CONTROL17-26
STEP 7. Check the harness wire between Engine ECU
connector B-21 terminal 14 and auto-cruise control switch
connector C-302 terminal 2 for damage.
Q: Are the harness wires in good condition?
YES : Go to Step 8.
NO : Repair the damaged harness wire if possible or as
recommended replace complete wiring harness and
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 8. Check the clock spring.
Refer to GROUP 52B, Air Bag Modules and Clock Spring
P.52B-244.
Q: Is the clock spring in good condition?
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). 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.
NO : Replace the clock spring and 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.

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 CONTROL17-28
STEP 11. 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 : 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 : 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.

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-29
STEP 12. Check Engine ECU connector B-21, intermediate
connector C-29, auto-cruise control switch connector
C-302 and clock spring connectors C-303 and C-306 for
loose, corroded or damaged terminals, or terminals
pushed back in the connector.

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-30
Q: Are the connectors and terminals in good condition?
YES : Go to Step 13.
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 13. Check the harness wire between Engine ECU
connector B-21 terminal 15 and auto-cruise control switch
connector C-302 terminal 3 for damage.
Q: Are the harness wires in good condition?
YES : Go to Step 14.
NO : Repair the damaged harness wire if possible, or
replace complete wiring harness and 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.

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 CONTROL17-34
DTC 1575: Cancel Latch Signal System
.
DTC SET CONDITIONS
The Engine ECU communicates cancellation reten-
tion information between the two microprocessors.
This DTC is set when cancellation retention informa-
tion contains inconsistency.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CODE TO BE
SET ARE:)
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
Replace the Engine ECU.[Refer to GROUP 13A, Engine ECU
13A-675] . Then check that diagnostic trouble code P1575 is
not set.

AUTO-CRUISE CONTROL
ENGINE AND EMISSION CONTROL17-35
DTC 1571: Stoplamp Switch System
.
CIRCUIT OPERATION
Battery positive voltage is supplied to the
stoplamp switch (terminal 2).
When the brake pedal is depressed, battery posi-
tive voltage is applied to the ENGINE-ECU (B-21)
(terminal 18).
.
DTC SET CONDITIONS
Check Condition
The "CRUISE" indicator lamp illuminates.
Judgement Criteria
Short in stop lamp switch circuit.
Open circuit in the brake switch circuit between
ENGINE-ECU(terminal 18) and ground.
.
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