Mitsubishi 380. Manual — part 347

AUTO-CRUISE CONTROL

ENGINE AND EMISSION CONTROL

17-56

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.

CAUTION

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

Step 6.

NO : Go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO-CRUISE CONTROL

ENGINE AND EMISSION CONTROL

17-57

STEP 2. Using Diagnostic Tool MB991958, check data list
item 75: Cancel Switch.

CAUTION

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.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO-CRUISE CONTROL

ENGINE AND EMISSION CONTROL

17-58

STEP 3. Using Diagnostic ToolDiagnostic Tool MB991958,
check data list item 74: Stoplamp Switch and data list item
89: Brake switch.

CAUTION

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.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO-CRUISE CONTROL

ENGINE AND EMISSION CONTROL

17-59

STEP 4. Using Diagnostic Tool MB991958, check A/T data
list item 34: Transmission Inhibitor Switch.

CAUTION

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.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827