Isuzu N-Series. Service manual — part 248

ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-57

Chart C-1-2 FR Speed Sensor Output Inspection Procedure

Chart C-1-3 RL Speed Sensor Output Inspection Procedure

Step

Action

Value(s)

YES

NO

1

1. Turn the key off.
2. Disconnect EHCU connector.
3. Jack up the vehicle, with all wheels off the

ground.

4. Measure the AC voltage between J-177

EHCU connector terminals 10 and 11
while turning FR wheel at a speed of 0.5
RPS.

Does the DVM display a voltage within the
specified value?

200 mV or

more

Go to Step 5

Go to Step 2

2

1. Disconnect FR sensor connector.
2. Using DVM, measure the resistance be-

tween J-74 sensor connector terminals 1
and 2.

Does the DVM display a resistance within the
specified value?

1.0 — 2.0 k

ohms

Go to Step 4

Go to Step 3

3

1. Locate open circuit, poor connection or

short circuit on the harness between
EHCU and sensor connectors.

2. Repair the harness.

Is action complete?

—

Go to Step 5

—

4

Replace FR sensor.

Is action complete?

—

Go to Step 5

—

5

1. Reconnect all components, ensure all

components are properly mounted.

2. Clear diagnostic trouble code.

Was this step finished?

—

Go to “Basic diag-

nostic flow chart”.

—

Step

Action

Value(s)

YES

NO

1

1. Turn the key off.
2. Disconnect EHCU connector.
3. Jack up the vehicle, with all wheels off the

ground.

4. Connect a 120 ohms resistor between J-

177 EHCU connector terminal 22 and
ground. Apply voltage of 12 V to EHCU
connector terminal 22.

5. Using DVM, measure the DC voltage be-

tween J-177 connector terminal 22 and
ground while turning RL wheel at a speed
of 0.5 RPS.

Does the DVM display a voltage within the
specified value?

0.2 — 4.5 V

Go to Step 5

Go to Step 2

5A4-58 ANTI-LOCK BRAKE SYSTEM (ABS)

2

1. Turn the key off.
2. Disconnect RL sensor connector.
3. Connect a 120 ohms resistor between

sensor connector terminal 2 (sensor side)
and ground.

4. Apply 12 V voltage at sensor connector

terminal 1 (sensor side).

5. Using DVM, measure the DC voltage be-

tween sensor connector terminal 2 (sen-
sor side) and ground while turning RL
wheel at a speed of 0.5 RPS.

Does the DVM display a voltage within the
specified value?

0.2 — 4.5 V

Go to Step 3

Go to Step 4

3

1. Locate open circuit, poor connection short

circuit on the harness between EHCU and
sensor connectors.

2. Repair the harness.

Is action complete?

—

Go to Step 5

—

4

Replace RL sensor.

Is action complete?

—

Go to Step 5

—

5

1. Reconnect all components, ensure all

components are properly mounted.

2. Clear diagnostic trouble code.

Was this step finished?

—

Go to “Basic diag-

nostic flow chart”.

—

Legend

1. Battery

3. Resistor

2. DVM

4. Speed Sensor

Step

Action

Value(s)

YES

NO

N5A1039E

ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-59

Chart C-1-4 RR Speed Sensor Output Inspection Procedure

Step

Action

Value(s)

YES

NO

1

1. Turn the key off.
2. Disconnect EHCU connector.
3. Jack up the vehicle, with all wheels off the

ground.

4. Connect a 120 ohms resistor between J-

177 EHCU connector terminal 21 and
ground.

5. Using DVM, measure the DC voltage be-

tween J-177 connector terminal 21 and
ground while turning RR wheel at a speed
of 0.5 RPS.

Does the DVM display a voltage within the
specified value?

0.2 — 4.5 V

Go to Step 5

Go to Step 2

2

1. Turn the key off.
2. Disconnect RR sensor connector.
3. Connect a 120 ohms resistor between

sensor connector terminal 2 (sensor side)
and ground.

4. Apply 12 V voltage at sensor connector

terminal 1 (sensor side).

5. Using DVM, measure the DC voltage be-

tween sensor connector terminal 2 (sen-
sor side) and ground while turning RR
wheel at a speed of 0.5 RPS.

Does the DVM display a voltage within the
specified value?

0.2 — 4.5 V

Go to Step 3

Go to Step 4

3

1. Locate open circuit, poor connection short

circuit on the harness between EHCU and
sensor connectors.

2. Repair the harness.

Is action complete?

—

Go to Step 5

—

4

Replace RR sensor.

Is action complete?

—

Go to Step 5

—

5

1. Reconnect all components, ensure all

components are properly mounted.

2. Clear diagnostic trouble code.

Was this step finished?

—

Go to “Basic diag-

nostic flow chart”.

—

5A4-60 ANTI-LOCK BRAKE SYSTEM (ABS)

Chart TC-1 Sensor Output Inspection Procedure (Use Tech 2)

Legend

1. Battery

3. Resistor

2. DVM

4. Speed Sensor

Step

Action

Value(s)

YES

NO

1

1. Connect Tech 2.
2. Check the minimum speed of each sensor

by WHEEL SENSORS.

Is sensor speed within the specified value?

More than 4

km/h (3 mph)

Go to Step 2

Go to Step 6

2

Check the sensor harness for suspected dis-
connection (check while shaking harness/con-
nector).

Is the sensor harness connection normal?

—

Replace speed

sensor.

Go to Step 3

Repair.

Go to Step 2

3

Check the minimum speed of each sensor by
WHEEL SENSORS.

Is sensor speed within the specified value?

More than 4

km/h (3 mph)

Go to Step 4

Go to Step 6

4

Check the sensor rotor.

Is the sensor rotor normal?

—

Go to Step 5

Replace sensor

rotor.

Go to Step 5

5

Check the minimum speed of each sensor by
WHEEL SENSORS.

Is sensor speed within the specified value?

More than 4

km/h (3 mph)

Repair harness or

connector

between EHCU

and speed sensor.

Go to Step 6

Go to Step 6

6

Reconnect all components, ensure all compo-
nents are properly mounted.

Was this step finished?

—

Repeat the “Basic

diagnostic flow

chart”.

—

N5A1039E