Mitsubishi Galant 9G. Manual - part 454

AUTO-CRUISE CONTROL

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ENGINE AND EMISSION CONTROL

17-34

.

CIRCUIT OPERATION

• Battery positive voltage is supplied to the stop-

light switch (terminal 2 and 3).

• When the brake pedal is depressed, battery posi-

tive voltage is applied to the PCM (terminal 9 and 
33).

.

DTC SET CONDITIONS

Check Condition

• The "CRUISE" indicator light illuminates.

Judgement Criteria

• Short in stop light switch circuit.

• Open circuit in the brake switch circuit (between 

PCM terminal 33 and ground).

.

TROUBLESHOOTING HINTS (THE MOST 
LIKELY CAUSES FOR THIS CASE:)

• Malfunction of the stoplight switch.

• Damaged harness or connector.

• Malfunction of the PCM.

AC305710

B-20 HARNESS

CONNECTOR:

COMPONENT SIDE

B-19 HARNESS

CONNECTOR:

COMPONENT SIDE

AB

B-19 (B)

B-20

CONNECTORS: B-19, B-20

AIR CLEANER

PCM

AC305232AD

CONNECTORS: C-01, C-30

C-30 HARNESS
CONNECTOR:
COMPONENT SIDE

C-30

C-01

C-01 HARNESS
CONNECTOR:
CONPONENT SIDE

AUTO-CRUISE CONTROL

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ENGINE AND EMISSION CONTROL

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DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

• MB991223: Harness Set

• MB991923: Power Plant ECU Check Harness

STEP 1. Using scan tool MB991958, check data list item 05: 
Stoplight Switch.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958. 
(1) Connect scan tool MB991958 to the data link connector. 

(Refer to 

P.17-11

).

(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to data reading mode for 

auto-cruise control system. (Refer to 

P.17-11

).

• Item 05, Stoplight Switch.

• When the brake pedal is depressed, the display on 

scan tool MB991958 should be "ON".

• When the brake pedal is released, the display on 

scan tool MB991958 should be "OFF".

(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect scan tool MB991958.
Q: Is the switch operating properly?

YES : Go to Step 14.
NO :  Go to Step 2.

STEP 2. Check the stoplight operation.

Check the stoplight operation.

• When the brake pedal is depressed, the stoplight will 

illuminate.

• When the brake pedal is released, the stoplight does not 

illuminate.

Q: Is the stoplight will illuminate (when the brake pedal is 

depressed) and the stoplight does not illuminate (when 
the brake pedal is released)?
YES : Go to Step 3.
NO :  Go to Step 6.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO-CRUISE CONTROL

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ENGINE AND EMISSION CONTROL

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STEP 3. Measure the terminal voltage at PCM connector 
B-19.
(1) Disconnect all the connectors from the PCM.

(2) Connect special tool MB991923 between the PCM and the 

body-side harness connector.

(3) Turn the ignition switch to the "ON" position.

AC305710

B-19 HARNESS

CONNECTOR:

COMPONENT SIDE

AC

B-19 (B)

CONNECTOR: B-19

AIR CLEANER

PCM

AC209793AI

PCM

MB991923

BODY SIDE
HARNESS

SPECIAL TOOL 18-PIN CONNECTOR
(PCM CONNECTOR B-19)

B-19 (B)

4 3 2 1

7 6 5

8 9

11 10

14 13 12

18 17 16 15

AUTO-CRUISE CONTROL

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ENGINE AND EMISSION CONTROL

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(4) Measure the terminal voltage between special tool 18-pin 

connector terminal 9 (PCM connector B-19 terminal 9) and 
ground.

• When the brake pedal is depressed, the voltage should 

measure battery positive voltage (approximately 12 
volts).

• When the brake pedal is released, the voltage should 

measure 1 volt or less.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
(6) Disconnect special tool MB991923 between the PCM and 

the body-side harness connector.

(7) Reconnect all the connectors to the PCM.
Q: Is the measured voltage battery positive voltage 

(approximately 12 volts) when the brake pedal is 
depressed and 1 volt or less when the brake pedal is 
released?
YES : Go to Step 13.
NO :  Go to Step 4.

AC209617AB

SPECIAL TOOL 18-PIN
CONNECTOR:
COMPONENT SIDE