Mitsubishi Montero (2002-2004). Manual — part 1100

M-ASTC DIAGNOSIS

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MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-17

DTC 36, 38: Communication error in power control module

CAUTION

If the diagnostic trouble code(s), which indicate a
communication error in the power control mod-
ule, has been set, diagnose the CAN main bus
line.

.

CIRCUIT OPERATION
The M-ASTC-ECU gathers information regarding the
engine and automatic transmission, through the CAN
bus line from the power control module.

.

M-ASTC DTC SET CONDITION
DTC 36 is set if the M-ASTC-ECU cannot gather all
information regarding the engine from the PCM. DTC
38 is set if the ECU cannot gather all information
regarding the automatic transmission from the PCM.

.

TROUBLESHOOTING HINTS
The most likely causes for DTC 36, 38 to set are:

• The CAN bus line is defective.

• Damaged connector(s)

• The power control module is defective

• The M-ASTC-ECU is defective.

AC205062

CAN Bus Communication Circuit (powertrain control module)

AB

M-ASTC DIAGNOSIS

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MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-18

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991502: Scan Tool (MUT-II)

STEP 1. CAN main bus line diagnostics

CAUTION

If DTC 36 or 38 is set, diagnose the CAN main bus line.
Diagnose the CAN main bus line. Refer to

P.35C-60

.

If the CAN main bus line is repaired, check that the diagnostic
trouble code resets.
Q: Have you completed checking or repairing the CAN

main bus line?
YES :

• If the CAN main bus line is repaired, go to Step 3 .

• If the CAN main bus line is not defective, go to

Step 2.

NO : Diagnose the CAN main bus line. Refer to

P.35C-60

.

STEP 2. Check for engine and automatic transmission
DTCs.
Check whether engine and automatic transmission DTCs are
set or not.
Q: Are engine and automatic transmission DTCs set?

YES : Diagnose the power control module. Refer to

P.13Ab-

22

.

NO : Replace the M-ASTC-ECU, and then go to Step 3.

STEP 3. Recheck for diagnostic trouble code.
Q: Does DTC 36 or 38 reset?

YES : Return to Step 1.
NO : The procedure is complete.

M-ASTC DIAGNOSIS

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MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-19

DTC 47: Defective Cut Valve
DTC 48: Defective Pressure-increase Valve

.

CIRCUIT OPERATION
As the ignition switch is turned ON, power is supplied
to each solenoid valve via the valve relay. M-ASTC-
ECU, by turning ON the transistor, grounds the circuit
and turns the solenoid valve ON.

.

M-ASTC DTC SET CONDITIONS
The M-ASTC-ECU constantly monitors the solenoid
valve drive circuits. These codes are output if the M-
ASTC-ECU judges that there is an open circuit or
short-circuit in a solenoid coil or harness because the
solenoid valve is on but no current flows to the sole-
noid valve, or if current continues flowing to the sole-
noid valve even though the solenoid valve is off.

.

AC205065

Cut Valve and PI Valve Circuit

AB

AC204169 AC

CONNECTORS: B-14, B-18

B-14(B)

B-18(B)

AC204176

CONNECTOR: E-119

AN

M-ASTC DIAGNOSIS

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MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-20

TROUBLESHOOTING HINTS (The most likely
causes for these DTCs to set are:)

• The hydraulic brake booster (HBB) is defective.

• Damaged harness wires and connectors

• The M-ASTC-ECU is defective.

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991502: Scan Tool (MUT-II)

STEP 1. Check for M-ASTC DTC.
Check that the M-ASTC-ECU sets any other DTCs than 47 or
48.
Q: Does the M-ASTC-ECU set any other DTCs than 47 or

48?
YES : First diagnose the other DTCs.
YES : Go to Step 2.

STEP 2. Check the solenoid valve drive circuit. Measure at
M-ASTC-ECU connector E-119 by backprobing.
(1) Measure the voltage by backprobing (i.e. without

disconnecting M-ASTC-ECU connector E-119).

(2) Turn the ignition switch to the "ON" position.
(3) Measure voltage between the following terminals. It should

be approximately 12 volts (battery positive voltage).

When DTC 47 is set:

• M-ASTC-ECU connector E-119 terminal 6 and ground

•The voltage should measure battery voltage (approxi-

mately 12 volts).

When DTC 48 is set:

• M-ASTC-ECU connector E-119 terminal 5 and ground

• The voltage should measure battery voltage (approxi-

mately 12 volts).

Q: Does the voltage measure battery voltage

(approximately 12 volts)?
YES : Go to Step 3.
NO : Go to Step 4.

AC204176

CONNECTOR: E-119

HARNESS
SIDE

AJ

9

8

21 20

31 30

7

6

5

4

3

2 1

18

28

1716

13

27

15

25

14

26

12

24

11

23

10

22

19

29

AC204580

COMPONENT SIDE: E-119

AQ

1 2

10 11

22 23

3

4

5

6

7

8

9

13

25

1415

18

26

16

27

17

28

19

29

20

30

21

31

12

24

AC204580

COMPONENT SIDE: E-119

AP

1 2

10 11

22 23

3

4

5

6

7

8

9

13

25

1415

18

26

16

27

17

28

19

29

20

30

21

31

12

24