Isuzu N-Series. Manual - part 274

5A4-70 ABS/ASR

Electronic Hydraulic Control Unit (EHCU)

Components

Legend

1. Pipe
2. EHCU
3. Connector

4. Bracket
5. Cover

Removal

CAUTION:

• When performing electric-arc welding on the vehi-

cle, remove the EHCU before starting welding
work.

• When removing the EHCU from the vehicle, dis-

connect the battery cable first, and then disconnect
the connector. Connect in the reverse order of dis-
connection.

• Do not place intense radio emission equipment

such as radio device near the EHCU.

• Do not pour water to the EHCU directly.

• Never loosen the screw of the EHCU body. Nor ap-

ply paint to the EHCU body.

• Do not let metal products directly contact with the

connector pin terminals, including screwdriver and
or tester probe.

• Use special care for electrostatic.

• Do not directly apply external voltage to the termi-

nals.

N5A2039E

ABS/ASR 5A4-71

• When handling, do not hold the pipe of the upper

EHCU.

• Never loosen the bolts and nuts of the EHCU body.

If loosened, that EHCU must not be used anymore.

1. Cover

• Remove the cover.

2. Harness connector

• If the harness is fixed to the EHCU bracket,

loosen the fixing clip.

Legend

1. Lever
2. Lever lock
3. Clip
4. Fixed to EHCU bracket.

• Unlock the connector. Pull down the lever lock

to the unlock position.

Notice:

Make sure the lock portion (A portion) is in the unlock
position.

Legend

1. Lever lock
2. Lever
3. Lock portion (A portion)
4. Housing

• Operate the lever.

Notice:

Operate the lever till the lever becomes heavy. Then
change the force direction to the downward of the con-
nector. (See illustration.) Applying force to the EHCU-
side may damage the connector.

Legend

1. Lever
2. Lever operation (rotation direction)
3. Force applied direction when operating lever

1

2

3

4

N5A2040E

1

2

3

4

N5A2041E

1

2

3

N5A2042E

5A4-72 ABS/ASR

• Move the connector to the opposite side of the

EHCU to remove.

Notice:

With the lever in stop position, make sure that the lever
surface (lock portion side) is almost perpendicular to the
connector before removing the connector.

Legend

1. Lever
2. Connector
3. Lever lock

3. Brake pipe

• Disconnect the six brake pipes.

4. EHCU fixing nut

• Disconnect the three nuts fixing the EHCU.

5. EHCU

• Remove the EHCU.

6. Bracket

• Remove the bracket.

Installation

CAUTION:

• Be sure to use ground bolt to install the ground.
• Make sure there is no dust or foreign materials in

and around the pipe connection.

• Be careful that the pipe is connect to correctly.

• After EHCU installation, bleed air from the brake

system completely. Remove the fuse (FL-9 (40A))
of ABS to deactivate the ABS before air bleeding
operation.

• Be sure to use fresh specified brake fluid.

1. Bracket

• Install the bracket to the frame if it has been re-

moved.

2. EHCU

• Install the EHCU to the bracket.

3. EHCU fixing nut

• Install the EHCU fixing nuts.

Tighten:

Nut to 22 N

⋅m (2.2 kg⋅m / 16.2 lb⋅ft)

4. Brake pipe

• Install the brake pipe.

Tighten:

Brake pipe to 16 N

⋅m (1.6 kg⋅m / 11.8 lb⋅ft)

5. Harness connector

• Align the harness-side connector with the

EHCU-side connector.

Legend

1. EHCU-side connector
2. Lever
3. Housing
4. Harness
5. Lever lock

• Insert the harness-side connector to the EHCU-

side connector.

Notice:

The lever moves approx. 30° when the connector is in-
serted.

EHCU

3

3

1

2

Harness

N5A2043E

1

2

4

5

3

N5A2044E

ABS/ASR 5A4-73

Legend

1. Pushing direction
2. Harness-side connector

• Operate the lever to lock the lever lock to the

housing.

Legend

1. Lever

• If the harness was fixed to the EHCU bracket,

fix the harness with the fixing clip.

Legend

1. Lever
2. Lever lock
3. Clip
4. Fixed to EHCU bracket.

6. Cover

• Install the cover.

Legend

1. Master cylinder (front wheel)
2. Master cylinder (rear wheel)
3. RR wheel master cylinder
4. RL wheel master cylinder
5. FR wheel master cylinder
6. FL wheel master cylinder

1

2

EHCU

30

Harness

N5A2045E

1

N5A2046E

1

2

3

4

N5A2040E

N5A2047E