Mitsubishi 380. Manual — part 954

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-41

DTC C1226/C1231/C1236/C1241/C1246/C1251/C1256/C1261: ABS Solenoid Valve

CAUTION

If there is any problem in the CAN bus lines, an
incorrect diagnostic trouble code may be set.
Prior to this diagnosis, diagnose the CAN bus
lines.

NOTE: If the ABS-8 ECU or the active wheel
speed sensor are disconnected, or if the wiring is
an open/ short circuit, the ABS 8 ECU will shut
off power supply to the respective wheel speed
sensor. All other wheel speed sensors will oper-
ate normally. To restore the power supply, the
ignition switch must be turned to the "OFF" posi-

tion then to the "ON" position again.

.

CIRCUIT OPERATION

• The ABS-ECU contains the power supply circuit

(terminal 3) for the solenoid valve. The solenoid
valve is energized by a MOSFET driver, which is
integrated in the ABS-ECU.

• A MOSFET driver, which is integrated in the

ABS-ECU, is always energizing the solenoid
valve unless the initial check is in progress when
the ignition switch is turned on.

• The ABS-ECU activates the solenoid valve by

turning on its driving transistor.

35DB090A

A

FUSIBLE LINK
ABS (motor supply)
No. 3 (30 A)

FUSIBLE LINK
ABS (solenoid valve)
(20 A)

RELAY BOX

35DB091A

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-42

.

ABS DTC SET CONDITIONS

These diagnostic trouble codes will be set under the
cases below.

• The solenoid valve is not energized even after

the ABS-ECU has turned on the driving transistor
(Open circuit is present in the power supply cir-
cuit to the ABS-ECU solenoid valve, or the valve
relay has failed).

• The solenoid valve is not energized even after

the ABS-ECU has turned on the driving transistor
(Open circuit is present in the solenoid valve cir-
cuit inside the ABS-ECU, or the valve relay has
failed).

• After the ABS-ECU has turned off the driving

transistor, the solenoid valve still remains ener-
gized (short in the solenoid valve circuit).

• When a solenoid valve failure is detected

.

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

Current trouble

• Damaged wiring harness or connector

• Malfunction of the hydraulic unit (integrated with

ABS-ECU)

.

Past trouble

• Carry out diagnosis with particular emphasis on

connector(s) or wiring harness between the
power supply circuit (terminal 3) to the ABS-ECU
solenoid valve or ground circuit (terminal 1) . For
diagnosis procedures, refer to "How to cope with
past trouble" (Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

P.00-16

).

Circuit drawings

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

.

DIAGNOSIS

Required Special Tools:

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

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

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

• MB991219: Inspection Test Harness

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-43

STEP 1. Using diagnostic tool MB991958, diagnose the
CAN bus line.

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.

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the CAN bus line found to be normal?

YES : Go to Step 3.
NO : Repair the CAN bus line (Refer to GROUP 54C,

Diagnosis

P.54C-15

). Then go to Step 2.

STEP 2. Recheck for 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) Erase the DTC.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is DTC C1226, C1231, C1236, C1241, C1246, C1251,

C1256 or C1261 set?
YES : Go to Step 3.
NO : The procedure is complete.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-44

STEP 3. Measure the voltage at ABS-ECU connector A-02.
(1) Disconnect the connector A-02, and use special tool

Inspection Check Harness (MB991219) to probe the wiring
harness-side connector.

NOTE: The special tool (Inspection test harness)
MB991219 for connector pin contact pressure should be
used. The test probe should never be forcibly inserted, as it
may cause a defective contact.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 3 and ground. It

should be approximately 12 volts (battery positive voltage).

Q: Is the voltage approximately 12 volts (battery positive

voltage)?
YES : Go to Step 5.
NO : Go to Step 4.

35DB092A

CONNECTOR: A-02

HYDRAULIC UNIT

(WITH BUILT-IN ABS-ECU)

TEST

HARNESS

(MB991219)