Isuzu N-Series. Manual - part 247

ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-53

Chart 15 (DTC63/C0263) Abnormal RL Speed Sensor Signal

21

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

Have the vehicle been jacked up?

Have two or three wheels been turned on the
brake tester intentionally?

—

Be careful that the 

system may fail if 

two or three 

wheels are turned 

forcibly.

The flow is now 

complete.

Repair tires.

Go to Step 2

2

Are tire pressures, sizes and wear normal?

—

Go to Step 3

Repair tires.

Go to Step 2

3

Is there play in the RL wheel bearing?

—

Go to Step 10

Go to Step 4

4

Is there play in the RL speed sensor/sensor
rotor?

—

Go to Step 11

Go to Step 5

5

Is there powdered iron sticking to RL speed
sensor/sensor rotor?

—

Go to Step 12

Go to Step 6

6

Check the RL speed sensor. (Refer to Chart
C-1-3 or TC-1)

Is the RL sensor output normal?

—

Go to Step 7

Go to Step 9

7

Is there a broken tooth or indentation in the
sensor rotor?

—

Go to Step 13

Go to Step 8

8

1. Clear diagnostic trouble code.
2. Test drive and perform system self-check.

Does the DTC repeat?

—

Go to Step 17

Go to Step 16

9

Is there damage or indentation in the speed
sensor?

—

Go to Step 14

Go to Step 15

10

Adjust wheel bearing preload.

Is action complete?

—

Go to Step 18

—

11

Repair or replace speed sensor/sensor rotor.

Is action complete?

—

Go to Step 18

—

12

Repair speed sensor/sensor rotor.

Is action complete?

—

Go to Step 18

—

13

Replace sensor rotor.

Is action complete?

—

Go to Step 18

—

14

Replace RL speed sensor.

Is action complete?

—

Go to Step 18

—

15

Check the RL speed sensor circuit. Refer to
Chart 11.

Is action complete?

—

Verify repair

—

Step

Action

Value(s)

YES

NO

5A4-54 ANTI-LOCK BRAKE SYSTEM (ABS)

Chart 16 (DTC64/C0264) Abnormal RR Speed Sensor Signal

16

Check for a poor connection and an open cir-
cuit on the harness between EHCU and sen-
sor connectors.
Refer to “Note on Intermittents” described in
earlier this section.

Is action complete?

—

Go to Step 18

—

17

Replace EHCU.

Is action complete?

—

Go to Step 18

—

18

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

Have the vehicle been jacked up?

Have two or three wheels been turned on the
brake tester intentionally?

—

Be careful that the 

system may fail if 

two or three 

wheels are turned 

forcibly.

The flow is now 

complete.

Repair tires.

Go to Step 2

2

Are tire pressures, sizes and wear normal?

—

Go to Step 3

Repair tires.

Go to Step 2

3

Is there play in the RR wheel bearing?

—

Go to Step 10

Go to Step 4

4

Is there play in the RR speed sensor/sensor
rotor?

—

Go to Step 11

Go to Step 5

5

Is there powdered iron sticking to RR speed
sensor/sensor rotor?

—

Go to Step 12

Go to Step 6

6

Check the RR speed sensor. (Refer to Chart
C-1-4 or TC-1)

Is the RR sensor output normal?

—

Go to Step 7

Go to Step 9

7

Is there a broken tooth or indentation in the
sensor rotor?

—

Go to Step 13

Go to Step 8

8

1. Clear diagnostic trouble code.
2. Test drive and perform system self-check.

Does the DTC repeat?

—

Go to Step 17

Go to Step 16

9

Is there damage or indentation in the speed
sensor?

—

Go to Step 14

Go to Step 15

10

Adjust wheel bearing preload.

Is action complete?

—

Go to Step 18

—

11

Repair or replace speed sensor/sensor rotor.

Is action complete?

—

Go to Step 18

—

12

Repair speed sensor/sensor rotor.

Is action complete?

—

Go to Step 18

—

Step

Action

Value(s)

YES

NO

ANTI-LOCK BRAKE SYSTEM (ABS) 5A4-55

13

Replace sensor rotor.

Is action complete?

—

Go to Step 18

—

14

Replace RR speed sensor.

Is action complete?

—

Go to Step 18

—

15

Check the RR speed sensor circuit. Refer to
Chart 12.

Is action complete?

—

Verify repair

—

16

Check for a poor connection and an open cir-
cuit on the harness between EHCU and sen-
sor connectors.
Refer to “Note on Intermittents” described in
earlier this section.

Is action complete?

—

Go to Step 18

—

17

Replace EHCU.

Is action complete?

—

Go to Step 18

—

18

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

5A4-56 ANTI-LOCK BRAKE SYSTEM (ABS)

UNIT INSPECTION PROCEDURE

Unit Inspection Procedure

This section describes the following inspection procedures referred to during “SYMPTOM DIAGNOSIS” and “DIAG-
NOSS BY ‘ABS’ WARNING LIGHT ILLUMINATION PATTERN”:

Chart C-1-1 FL Speed Sensor Output Inspection Procedure

without Tech 2

with Tech 2

Speed Sensor Output Inspection

Chart C-1-1 to C-1-4

Chart TC-1

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 32 and 33
while turning FL 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 FL sensor connector.
2. Using DVM, measure the resistance be-

tween J-75 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 FL 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”.

—