2000 MITSUBISHI MONTERO Service Repair Manual

BASIC BRAKE SYSTEM -Troubleshooting35A-9
INSPECTION CHART FOR DIAGNOSIS CODES
Diagnosis
code No.Diagnosis itemsReference page
16*ABS-ECU power supply (Abnormal voltage decrease or increase)35A-9
17, 18ABS-ECU power supply (Open circuit or short circuit)
53Motor relay system (open circuit, short circuit or motor relay coil failure)35A-10
55Pump motor system (Pump motor seized or abnormal ABS-ECU current
detection circuit)35A-11
63ABS-ECU systemReplace ABS-ECU
(Refer to 35B.)
78Accumulator system (Motor has been energized abnormally for long time
or abnormal low-pressure accumulator)35A-12
79Pressure switch system (open circuit or short circuit)35A-13
NOTE
*: Code No. 16 is erased by turning the ignition switch OFF.
INSPECTION PROCEDURE FOR DIAGNOSIS CODES
Code No.16 ABB-ECU power supply system (abnormal
voltage increase or decrease)Probable cause
Code No.17, 18 ABS-ECU power supply system (open or
short circuit)
Code No.16 is output if the ABS-ECU power supply voltage is increased or decreased
than the specified.
Code No.17, 18 is output if the ABS-ECU power supply circuit isopen orshort, or
the ABS-ECU internal circuit is defective.
In addition, code No. 16 is erased by turning the ignition switch OFF.DMalfunction of the battery
DMalfunction of connector or harness
DMalfunction of the ABS-ECU
Caution
If the battery voltage is decreased or increased during the test, code No. 16 is output as a present
malfunction, disabling a correct diagnosis. Check the battery and fully charge it if necessary before
carrying out the following tests.
NG
NG
OK
NG
Replace the ABS-ECU. (Refer to GROUP 35B.)
OK
Check trouble symptom.
NG
Repair
NG
Check the harness wire, and repair if necessary.
DBetween the ignition switch and the ABS-ECU
OK
Check trouble symptom.
Measure at the ABS-ECU connector E-107.
DDisconnect the connector, and measure at the harness side.
DStart theengine and then measure the voltage between terminal
31 and the body earth.
OK:System voltageNGCheck the following connectors:E-13, E-107
Repair
OK
Check the following connectors:E-106, E-107
NG
Check the harness wire, and repair if necessary.
DBetween the ignition switch and the ABS-ECU
OK
Check trouble symptom.
Measure at the ABS-ECU connector E-106.
DDisconnect the connector, and measure at the harness side.
DStart theengine and then measure the voltage between terminal
13 and the body earth.
OK:System voltageNG
Check the following connectors:D-32 ,
D-128, D-208, D-210 , D-213 vehicles>, E-08 , E-13, E-106
Repair


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BASIC BRAKE SYSTEM -Troubleshooting35A-10
Code No.53 Motor relay system (open circuit, short circuit
or a defective motor relay coil)Probable cause
This code is output if the motor relay circuit is short or open, ABS-ECU internal circuit
is defective, or the hydraulic brake booster (HBB) master cylinder and hydraulic unit
assembly is defective.DMalfunction of connector or harness
DMalfunction of the motor relay
DMalfunction of the ABS-ECU
DMalfunction of the HBB (master cylinder and
hydraulic unit assembly)
NG
Replace the ABS-ECU. (Refer to GROUP 35B.)NG
Repair
NG
OK
Check trouble symptom.
Repair NGNG
OK
Check trouble symptom.
Replace
OK
Check the following connectors:
B-17, B-18, B-19X, B-20X,
D-32 , D-128, D-208, D-210 vehicles>, D-213 , E-13, E-106, E-107
Check the harness wire:
DBetween the ignition switch and the motor relay
DBetween fusible link No.9 and the motor relay
DBetween the motor relay and HBB
DBetween the motor relay and the ABS-ECU
DBetween the HBB and the ABS-ECU
Check trouble symptom.
NG
NG
Replace
OK
Check the motor relay. (Refer to P.35A-24.)
Check the hydraulic brake booster (HBB).
(Refer to P.35A-23.)


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BASIC BRAKE SYSTEM -Troubleshooting35A-11
Code No.55 Pump motor system (pump motor seized or
abnormal ABS-ECU current detection circuit)Probable cause
This code is output if the motor relay drive circuit is short or open, the motor relay
or the ABS-ECU internal circuit is defective, or the hydraulic brake booster (HBB)
pump motor ormaster cylinder and hydraulic unit assembly is defective.DMalfunction of connector or harness
DMalfunction of the motor relay
DMalfunction of the ABS-ECU
DMalfunction of the HBB (pump motor or master
cylinder and hydraulic unit assembly)
NG
Repair
NG
OK
Check trouble symptom.
Repair NGNG
OK
Check trouble symptom.
Replace
OK
Check the following connectors:
B-17, B-18, B-19X, B-20X,
E-107
Check the harness wire:
DBetween fusible link No.9 and the motor relay
DBetween the motor relay and HBB
DBetween the HBB and the ABS-ECU
DBetween the HBB and the earthNG
Check the motor relay. (Refer to P.35A-24.)
NG
Replace the ABS-ECU. (Refer to GROUP 35B.)
Check trouble symptom.
NG
OKCheck the hydraulic brake booster (HBB).
(Refer to P.35A-23.)Replace NG
Replace
OKCheck the continuity and resistance of thepump motor.(Refer
to P.35A-23.)


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BASIC BRAKE SYSTEM -Troubleshooting35A-12
Code No. 78 Accumulator system (Motor has
been energized abnormally for long time or
abnormal low-pressure accumulator)Probable cause
This code is output under the following cases:
DPump motor is operated for consecutive 300 seconds
DBrake fluid pressure is decreased, the HBB buzzer sounds due
to the operation of the pressure switch (for low pressure
warning), and then the brake warninglamp illuminates.DBrake fluid leaks inside the hydraulic brake booster (HBB)
DMalfunction of the HB motor relay
DMalfunction of connector or harness
DMalfunction of the ABS-ECU
DMalfunction of HBB (accumulator, pressure switch,pump motor or
master cylinder and hydraulic unit assembly)
NG
Repair
NG
OK
Check trouble symptom.
Repair NGNG
OK
Check trouble symptom.
Replace
OK
Check the following connectors:
B-17, B-18, B-19X, B-20X,
E-106, E-107
Check the harness wire:
DBetween fusible link No.9 and the motor relay
DBetween the motor relay and HBB
DBetween the HBB and the ABS-ECU
DBetween the HBB and the earthNG
Check the motor relay. (Refer to P.35A-24.)
NG
Replace the ABS-ECU. (Refer to GROUP 35B.)
Check trouble symptom.
NG
OKCheck the pressure switch. (Refer to P.35A-23.)NG
Replace
OKCheck the continuity and resistance of thepump motor.(Refer
to P.35A-23.)NG
Replace
OKVisually check the accumulator
Replace the master cylinder and hydraulic unit assembly.


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BASIC BRAKE SYSTEM -Troubleshooting35A-13
Code No.79 Pressure switch system (open or short
circuit)Probable cause
This code is output if the pressure switch circuit is short, ABS-ECU internal circuit
is defective, or the hydraulic brake booster (HBB) pressure switch or master cylinder
and hydraulic unit assembly is defective.DMalfunction of connector or harness
DMalfunction of the ABS-ECU
DMalfunction of the HBB (pressure switch or master
cylinder and hydraulic unit assembly)
NG
Repair
NG
OKRepair NG
OK
Check trouble symptom.
Check the following connectors:
B-17, B-18, E-106, E-107
Check the harness wire:
DBetween the HBB and the ABS-ECU
DBetween the HBB and the earthNG
Check trouble symptom.
Replace the ABS-ECU. (Refer to GROUP 35B.)
NG
OKCheck the pressure switch. (Refer to P.35A-23.)Replace the master cylinder and hydraulic unit assembly.
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptomInspection
procedure
No.Reference page
The brake warning lamp does not illuminate when the ignition switch is turned ON
(engine stopped).135A-14
The brake warning lamp remains illuminated after the engine is started.235A-15
The HBB buzzer does not sound when the hydraulic brake booster (HBB) is
defective. (However, the brake warning lamp is illuminated.)335A-15
The HBB buzzer does not stop sounding.435A-16
Communication with MUT-II
is not possible.Refer to GROUP 35B.
Communication with MUT-II
and the ABS-ECU is not possible.


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BASIC BRAKE SYSTEM -Troubleshooting35A-14
Inspection procedure 1
The brake warning lamp does not illuminate when the
ignition switch is turned ON (engine stopped).
Probable cause
The cause may be anopencircuit in thelamppower supply circuit, a blown lamp,
a malfunction of the lampdrive transistor inside the ABS-ECU, anopencircuit between
the ignition switch and brake warninglamp or anshort circuit between the brake
warning lamp and theABS-ECU.DBlown fuse
DBurn out brake warninglamp bulb
DMalfunction of combination meter
DMalfunction of connector or harness
DMalfunction of ABS-ECU (lamp drive transistor)
Repair NG NG
NO
Replace the ABS-ECU. (Refer to GROUP 35B.)
Repair
Repair
NG
OK
Check for blown bulb.Replace the brake warninglamp bulb.
OK
Check the following connectors:
D-01, D-208, D-210 drive vehicles>, D-213
NG
Replace the combination meter. (Refer to GROUP 54.)
OK
Check trouble symptom.
OK
YES
Check multi-purpose fuse No.6.NGRefer to GROUP 00 – Inspection Procedure when a Fuse is blown.
Check the harness wire:
DBetween the ignition switch and the combination meter
Check the harness wire:
DBetween the combination meter and the ABS-ECU
Disconnect the ABS-ECU connector E-107. Does the brake warning
lamp illuminatewhen the ignition switch is turned ON?
NG
OK


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BASIC BRAKE SYSTEM -Troubleshooting35A-15
Inspection procedure 2
The brake warning lamp remains illuminated after the
engine is started.
Probable cause
The cause is probably malfunction of thelampdrive transistor inside the ABS-ECU
or an opencircuit between the brake warninglamp and theABS-ECU.DMalfunction of combination meter
DMalfunction of connector or harness
DMalfunction of ABS-ECU (lamp drive transistor)
NOTE
This trouble symptom is limited to cases where communication with the MUT-II is possible(ABS-ECU
power supply is normal) and the diagnosis code is a normal diagnosis code.
Repair NG
Repair
Replace the combination meter. (Refer to GROUP 54.)
OK
YESReplace the ABS-ECU. (Refer to GROUP 35B.)
NO
Disconnect the ABS-ECU connector E-107. Does the brake warning
lamp go outwhen the ignition switch is turned ON and No.39 terminal
is connected to the body earth.
OK
Check the following connectors:
D-01, E-13, E-107
Check trouble symptom.
Check the harness wire:
DBetween the combination meter and the ABS-ECUNG
NG
Inspection procedure 3
The HBB buzzer does not sound when the hydraulic brake
booster (HBB) is defective. (However, thebrake warning
lamp is illuminated.)
Probable cause
The cause is probably anopencircuit in the buzzer power supply circuit, a defective
buzzer, a malfunction of the buzzer drive transistor inside the ABS-ECU or anopen
circuit from the ignition switch through the HBB buzzer to the ABS-ECU.DBlown fuse
DMalfunction of the HBB buzzer
DMalfunction of connector or harness
DMalfunction of ABS-ECU (buzzer drive transistor)
Replace the ABS-ECU. (Refer to GROUP 35B.)
Repair NG
Repair
NG
OK
Check the HBB buzzer. (Refer to P.35A-40.)
OK
Check the following connectors:
D-32 ,
D-128, D-208, D-210 , D-213 vehicles>, E-08, E-13, E-107
NG
OK
Check trouble symptom.
Check multipurpose fuse No.5.NGRefer to GROUP 00 – Inspection Service Points for Blown Fuse.
Check the harnesse wire:
DBetween the ignition switch and the HBB buzzer
DBetween the HBB buzzer and the ABS-ECUNGReplace


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BASIC BRAKE SYSTEM -Troubleshooting35A-16
Inspection procedure 4
The HBB buzzer does not stop sounding.
Probable cause
The HBB buzzer circuit may be short.DMalfunction of the HBB buzzer
DMalfunction of the harness
DMalfunction of ABS-ECU (buzzer drive transistor)
NOTE
This trouble symptom is limited to cases where communication with the MUT-II
is possible (ABS-ECU
power supply is normal) and the diagnosis code is a normal diagnosis code.
OK
Repair NG
Repair
Replace the HBB buzzer.
OK
NG
YES
Replace the ABS-ECU. (Refer to GROUP 35B.)NODisconnect the ABS-ECU connector E-107. Does the HBB buzzer
remain sounding when the ignition switch is turned ON?
Check trouble symptom.
Check the harness wire:
DBetween the HBB buzzer and the ABS-ECUNG
Check the following connectors:
E-107, E-108
ACTUATOR TEST REFERENCE TABLE
The MUT-II activates the following actuators for testing.
NOTE
1. If the ABS-ECU runs down, actuator testing cannot be carried out.
2. Actuator testing is only possible when the vehicle is stationary.
ACTUATOR TEST SPECIFICATIONS
Item No.Inspection itemDrive contents
01HBB pump motorOperate the pump motor for one second.
02HBB buzzerSound the buzzer for three seconds.


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