2007 ISUZU KB P190 ECO mode

5A-46 BRAKE CONTROL SYSTEM
No ABS Warning Lamp

Step Action Value(s) Yes No
1 Check the meter fuse for the instrument cluster
ignition feed circuit.
Is the fuse OK? - Go to Step 3 Go to Step 2
2 Replace the fuse. Is the action complete? - Verify repair
Go to Step 3 -
3 1. Ignition “OFF”, disconnect the EHCU. 2. Ignition “ON”, engine “OFF”.
3. Observe the ABS warning lamp. Is the ABS warning lamp “ON”? - Go to Step 5 Go to Step 4
4 Repair or replace the meter circuit or meter.
Is the action complete? - Verify repair -
5 1. Check the EHCU circuit for an open, short to
ground, or short to voltage. Also, check the EHCU
ignition feed circuit for an open or short to ground
and the EHCU ground circuit for an open.
2. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 6
6 1. Ignition “OFF”, reconnect the EHCU.
2. Ignition “ON”,engine “OFF”.
3. Observe the ABS warning lamp. Is the ABS warning lamp “ON”? - Verify repair Go to Step 7
7 Replace EHCU.
Note: Check the EHCU type for specification, the
EHCU is replaced.
(Specification; 2W D or 4W D Model)
Is the action complete? - Verify repair -


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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-47
ABS Warning Lamp ON Steady

Step Action Value(s) Yes No
1 1. Check the ABS warning lamp lighting circuit for a
short.
2. If a problem found, repair as necessary. W as a problem found? - Go to Step 3 Go to Step 2
2 1. Check the ABS warning lamp lighting circuit at the
meter for a short. Refer to METER, W ARNING
LIGHT AND INDICATOR LIGHT in 8 section.
2. If a problem is found, repair or replace the meter. W as a problem found? - Go to Step 3 Go to Step 4
3 1. Connect all connectors.
2. Ignition “ON”, engine “OFF”.
3. W ait for about 10 seconds.
4. Observe the ABS warning lamp. Is the ABS warning lamp turned “OFF”? - Verify repair Go to Step 4
4 Replace EHCU.
Note: Check the EHCU type for specification, the
EHCU is replaced.
(Specification; 2W D or 4W D Model)
Is the action complete? - Verify repair -


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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-79
Step Action
Value(s) Yes No
6 1. Remove the G sensor.
2. Reconnect G sensor and EHCU
3. Install the Tech 2.
4. Ignition "ON", engine "OFF".
5. Observe the G sensor reading on Tech 2. If G sensor inclines, reading voltage will change.
Is the reading voltage between specified values? 1.0 - 4.0V Go to Step 7 Go to Step 8
7 1. Ignition "OFF". 2. Install the G sensor.
3. Install the Tech 2.
4. Ignition "ON", engine "OFF".
5. Select "Display DTCs" with the Tech 2. Are any DTCs stored? - Go to Step 8 Verify repair
8 1. Replace G sensor.
2. Select "Display DTCs" with the Tech 2. Note: Perform the various tests (actuator test, test
run, brake test, etc.) then observe the DTC with a
Tech 2.
Are any DTCs stored? - Go to Step 9 Verify repair
9 Replace EHCU.
Note: Check the EHCU type for specification, when
the EHCU is replaced.
(Specification ; 2W D model or 4W D model)
Is the action complete? - Verify repair -


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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-85
Step Action Value(s) Yes No
4 1. Ignition "OFF".
2. Check for a poor condition at the EHCU harness connector.
3. Check the EHCU circuit for an open, short to ground, or short to voltage. Also, check the EHCU
ignition feed circuit for an open or short to ground
and the EHCU ground circuit for an open or short to
voltage.
4. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 9
5 1. Ignition "OFF", disconnect the EHCU and G sensor.
2. Check the circuit between EHCU and G sensor. (short to ground, or short to voltage.)
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair
Go to Step 6 Go to Step 6
6 1. Remove the G sensor. 2. Reconnect G sensor and EHCU
3. Install the Tech 2.
4. Ignition "ON", engine "OFF".
5. Observe the G sensor reading on Tech 2. If G sensor inclines, reading voltage will change.
Is the reading voltage between specified values? 1.0 – 4.0 V Go to Step 7 Go to Step 8
7 1. Ignition "OFF". 2. Install the G sensor.
3. Install the Tech 2.
4. Ignition "ON", engine "OFF".
5. Select "Display DTCs" with the Tech 2. Are any DTCs stored? - Go to Step 8 Verify repair
8 1. Replace G sensor.
2. Select "Display DTCs" with the Tech 2. Note: Perform the various tests (actuator test, test
run, brake test, etc.) then observe the DTC with a
Tech 2.
Are any DTCs stored? - Go to Step 9 Verify repair
9 Replace EHCU.
Note: Check the EHCU type for specification, when
the EHCU is replaced.
(Specification ; 2W D model or 4W D model)
Is the action complete? - Verify repair -



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ISUZU KB P190 2007

BRAKES 5C-9
MAIN DATA AND SPECIFICATIONS
FRONT DISC BRAKE mm (in) 4 × 2 HIGH RIDE
4
× 2
4 × 4
Caliper type Pin slide
Disc outside diameter 256 (10.079) 280 (11.024)
Disc thickness 26 (1.024) 27 (1.063)
Piston diameter 42.8 (1.685) × 2 45.5 (1.791) × 2
Adjustment method Self-adjusting
REAR DRUM BRAKE mm (in) 4 × 2 HIGH RIDE
4
× 2
4 × 4
Type Leading and Trailing
Drum inside diameter 254 (10.000) 295 (11.614)
Brake lining dimension 244 × 50 × 5 283 × 45 × 5
(Length × W idth × Thickness) (9.61 × 1.97 × 0.20) (11.14 × 1.77 × 0.20)
Adjustment method Self-adjusting
W HEEL CYLINDER mm (in)
Inside diameter: rear 25.4 (1.000) 23.8 (0.937)
MASTER CYLINDER mm (in)
Type Split
Bore diameter 25.4 (1.000)
Piston stroke (Primary + Secondary) 21.8 + 12 (0.86 + 0.47)
VACUUM SERVO mm (in)
Diaphragm diameter 205 (8.071) + 230 (9.055)
Power cylinder stroke 35 (1.378)
PEDAL RATIO 3.7
BALANCE
Type Load sensing proportioning valve (without ABS) /
Blend proportioning valve (without ABS)/EBD (with ABS)



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ISUZU KB P190 2007

5C-20 BRAKES

•
••
•
Operation
The operation of the P-valve by the master cylinde
r
pressure is unchanged up to the brake points
A and B.
If master cylinder fluid pressure penetrates into the second break point
B, the fluid pressure pressing against the seal
, (which isolated route 4 and route 5), passing the route
4of the master cylinder side, overcomes the operating
force of the spring
3 + fluid pressure affecting the seal 2of
the wheel cylinder, and presses the piston
1to the right
side, resulting in the opening of the routes
4 and 5, and
canceling of the P-valve operation.
Then, because the master cylinder fluid pressure and the wheel cylinder fluid pressure, up to the point
C, operate on
the identical surface of the seal
, both have identical
ascending ratios.
However, because of the operation of spring
3in the wheel
cylinder side, wheel cylinder fluid pressure operates to
preserve the balance against the master cylinder fluid
pressure on the lower level with the difference in pressure
resulting from this spring.




RTW 75CSH001601

Valve Maintenance
In the case of a fluid leak or other abnormality, the faulty valve
should be replaced.
The valve is set up at the engine room.
Note:
The blend proportioning valve is not repairable and must
be replaced as a complete assembly.





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5C-24 BRAKES
RTW 35CSH000201
3) Rear wheel cylinder fluid pressure measurement
Step on the brake pedal until the fluid pressure of the front wheel cylinder gets to 9.8Mpa (100kg/cm
2), and
check the rear wheel cylinder fluid pressure. (Read the
value of the front wheel cylinder fluid pressure 2
seconds after the measurement. W hen measuring the
LSPV fluid pressure, keep the brake pedal pressed
down without stepping it down twice or releasing it.)
Rear W heel Cylinder Fluid Pressure MPa (kg/cm
2)
2W D 6.77 ±0.83 (69.0 ±8.5)
2W D (W ith High Ride
Suspension), 4W D 6.77
±0.83 (69.0 ±8.5)

RTW 35CSH000401
2. Oil Pressure Adjustment
1) LSPV spring length adjustment
Loosen the adjust nut of the LSPV spring joint, and adjust the length of the LSPV spring.
W hen the oil pressure is insufficient, turn the adjust nut clockwise to extend the span “A”. W hen the oil pressure
is too high, turn the adjust nut counterclockwise to
reduce the span “A”.


2) After adjustment, tighten the lock nut securely.
Lock Nut Torque N⋅m (kgf ⋅m/lb ⋅ft)
11-20 (1.1-2.0/8-14)


















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BRAKES 5C-25
Filling Master Cylinder Reservoir
CAUTION:
Use only specified brake fluid. Do not use any fluid which
contains a petroleum base. Do not use a container which
has been used for petroleum based fluids or a containe
r
which is wet with water. Petroleum based fluid will cause
swelling and distortion of rubber parts in the hydraulic
brake system. Water mixed with brake fluid lowers the
fluid boiling point. Keep all fluid containers capped to
prevent contamination.
Always fill the master cylinder reservoir when the engine
is cold.
Never allow the brake fluid to come in contact with the
painted surfaces.
The master cylinder reservoir must be kept properly filled
to ensure adequate reserve and to prevent air and
moisture from entering the hydraulic system. However,
because of expansion due to heat absorbed from the
brakes and the engine, the reservoir must not be
overfilled. Thoroughly clean reservoir cap before removal
to avoid getting dirt into reservoir. Add fluid as required to
bring level to the “MAX” mark on the reservoir tank. Use
“DOT 3” Hydraulic Brake Fluid.

Leakage of Brake Fluid
W ith engine idling, set shift lever in the neutral position and
continue to depress brake pedal at a constant pedal
application force.
Should the pedal stroke become deeper gradually, leakage
from the hydraulic pressure system is possible.
Make sure by visual check that there is no leak.




BLEEDING OF THE BRAKE HYDRAULIC
CIRCUIT
If air enters the bake lines, it will cause poor brake action.
Therefore, bleeding should be performed if the brakes have
been used with the level of brake fluid in the reservoi
r
excessively low or if brake pipes have been disconnected in
the course of brake servicing.
The bleeding operation calls for co-operative action of 2
persons.
• Set the parking brake firmly while bleeding.
• Perform bleeding operation with ENGINE RUNNING, to
prevent damage to push rod seal.
Make sure exhaust is suitably ventilated.
• Bleed the hydraulic system with the fluid reservoir filled to
the specified level.
• Bleed the system starting with the rear wheel cylinde
r
farthest from the master cylinder.


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ISUZU KB P190 2007