Mitsubishi Montero (2004+). Manual — part 1088

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-63

.

CIRCUIT OPERATION
The M-ASTC-ECU receives signals through the CAN
bus line from the steering wheel sensor, the G and
yaw rate sensor, and the power control module.

.

TECHNICAL DESCRIPTION (COMMENT)
If the Active skid control system does not work nor-
mally, the CAN main bus line or the terminator resis-
tor may be suspected (ECUs and the sensor may
also be suspected, and check the condition of the
CAN main bus line according to this diagnosis sec-
tion).

.

TROUBLESHOOTING HINTS

• The CAN main bus line may be defective

• The M-ASTC-ECU integrated or separate termi-

nator resistor may be defective

• The wiring harness or connectors may have

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector

DIAGNOSIS

Required Special Tools:

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

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

• MB991223: Harness Set

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-64

STEP 1. Measure the voltage in the CAN_L line. Measure at
data link connector D-117.

CAUTION

Before checking CAN bus lines and their interconnected
components, "ground" yourself, by touching a metal
object such as an unpainted pipe, this will discharge any
potentially damaging static that may have built up.

CAUTION

When measuring resistance value or voltage in CAN bus
lines, use a digital multimeter. If not using a digital multim-
eter, the equipments connected through the CAN bus lines
may be damaged.
(1) Disconnect resistor connector D-130 and M-ASTC-ECU

connector E-121, and measure the voltage at data link
connector D-117.

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

CAUTION

Always use the test harness when measuring the voltage
or resistance at the female connector. If you fail to do so,
connectors may be damaged.

(3) Measure the voltage between data link connector D-117

terminal 28 and body ground.

• The voltage should measure 0.5 volts or more, or 4.5

volts or less.

Q: Does the voltage measure 0.5 volts or more, or 4.5 volts

or less?
YES : Go to Step 2.
NO : Diagnose the CAN_L side bus line by referring to

P.35C-67

.

AC204170

CONNECTOR: D-117

HARNESS SIDE

AM

21

26

22

27 2829 30

23

31

24

32

25

33

AC204575

21

26

22

27 2829 30

23

31

24

32

25

33

HARNESS SIDE: D-117

AB

TEST
HARNESS

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-65

STEP 2. Measure the voltage in the CAN_H line. Measure at
DTC connector D-117.

CAUTION

Before checking CAN bus lines and their interconnected
components, "ground" yourself, by touching a metal
object such as an unpainted pipe, this will discharge any
potentially damaging static that may have built up.

CAUTION

When measuring resistance value or voltage in CAN bus
lines, use a digital multimeter. If not using a digital multim-
eter, the equipments connected through the CAN bus lines
may be damaged.
(1) Disconnect resistor connector D-130 and M-ASTC-ECU

connector E-121, and measure the voltage at data link
connector D-117.

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

CAUTION

Always use the test harness when measuring the voltage
or resistance at the female connector. If you fail to do so,
connectors may be damaged.

(3) Measure the voltage between data link connector D-117

terminal 23 and body ground.

• The voltage should measure 0.5 volts or more, or 4.5

volts or less.

Q: Does the voltage measure 0.5 volts or more, or 4.5 volts

or less?
YES : Go to Step 3.
NO : Diagnose the CAN_H side bus line by referring to

P.35C-96

.

AC204170

CONNECTOR: D-117

HARNESS SIDE

AM

21

26

22

27 2829 30

23

31

24

32

25

33

AC204575

21

26

22

27 2829 30

23

31

24

32

25

33

HARNESS SIDE: D-117

TEST
HARNESS

AC

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-66

STEP 3. Check the terminator resistor.

CAUTION

Before checking CAN bus lines and their interconnected
components, "ground" yourself, by touching a metal
object such as an unpainted pipe, this will discharge any
potentially damaging static that may have built up.

CAUTION

When measuring resistance value or voltage in CAN bus
lines, use a digital multimeter. If not using a digital multim-
eter, the equipments connected through the CAN bus lines
may be damaged.
(1) Measure the resistance at data link connector D-117.
(2) Turn the ignition switch to the LOCK (OFF) position.

CAUTION

Disconnect the negative battery terminal when measuring
the resistance value in the CAN bus line. If you fail to do
so, the equipments connected through the CAN bus lines
may be damaged.
(3) Disconnect the negative battery terminal.

CAUTION

Always use the test harness when measuring the voltage
or resistance at the female connector. If you fail to do so,
connectors may be damaged.
(4) Measure the resistance between data link connector D-117

terminals 23 and 28.

• The resistance should measure 60 ± 10 ohms.

Q: Does the resistance measure 60

± 10 ohms?

YES : Go to Step 4.
NO : Diagnose the terminator resistor and the CAN main

bus line by referring to

P.35C-125

.

STEP 4. Using scan tool MB991958, Using scan tool
MB991958, read the diagnostic trouble code.

Once the CAN main bus line has been diagnosed, erase all the
DTCs, and then check for the DTCs.
Q: Does DTC reset?

YES <DTC 36 or 38 is set> : Diagnose the CAN bus line

(between the main bus line and the power control
module). Refer to

P.35C-171

.

YES <DTC 67 is set> : Diagnose the CAN bus line

(between the main bus line and the steering wheel
sensor). Refer to

P.35C-176

.

YES <DTC 74 is set> : Diagnose the CAN bus line

(between the main bus line and the G and yaw rate
sensor). Refer to

P.35C-182

.

NO <no DTC is set> : Retest the system.

AC204170

CONNECTOR: D-117

HARNESS SIDE

AM

21

26

22

27 2829 30

23

31

24

32

25

33

AC204576

21

26

22

27 2829 30

23

31

24

32

25

33

HARNESS SIDE: D-117

TEST
HARNESS

AB

TEST
HARNESS