2007 ISUZU KB P190 Circuit

BRAKE CONTROL SYSTEM 5A-35
Diagnosis By “ABS” Warning Lamp
Illumination Pattern
In the event that there is abnormality in the “ABS”
W arning Lamp Illumination Pattern while the key is in
the “ON” position or if the warning lamp is actuated
during driving, the fault should be diagnosed on an
illumination pattern basis as follows:

No. Condition “ABS” Warning Lamp Illumination Pattern Diagnostic
1 W arning Lamp is
actuated normally
Normal
2 W arning Lamp is not
lit
W arning Lamp lighting circuit
trouble. Go to No ABS
W arning Lamp.
3 W arning Lamp remains ON
Diagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.
If diagnostic trouble codes are
not stored, it means warning
lamp lighting circuit or meter
trouble. Go to ABS warning
Lamp On Steady.
4 W arning Lamp is actuated while driving
Diagnostic trouble codes are
stored.
Display diagnostic trouble
codes and diagnose on a
code basis according to the
flow charts.
Diagnostic Trouble Codes (DTCs)
W hen the warning lamp in the meter remains ON, the
EHCU stores the fault identification and disables the
ABS.



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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-39
Step Action Value(s) Yes No
3 1. Ignition “OFF”, disconnect the EHCU.
2. Check the DLC (Data Link Connector) circuit for an open, short to ground, or short to voltage.
Also, check the DLC ignition feed circuit for an open
or short to ground and the DLC ground circuit for an
open.
3. If a problem is found, repair as necessary. W as a problem found? - Go to Step 2 Go to Step 4
4 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? - Go to Step 2 Go to Step 11
5 Select “Display DTCs” with the Tech 2.
Are any DTCs stored? - Go to Step 6 Go to Step 10
6 Review and record for Tech 2 Failure Records data
and DTCs.
Is the action complete? - Go to Step 7 -
7 The DTC is then stored. Is this DTC C0271 stored?
- Go to
applicable
DTC table
after Go to step 8 Go to Step 8
8 Clear the DTCs by “Clear the Information“ with Tech 2.
Did the DTCs clear? - Go to Step 9 -
9 Select “Display DTCs” with the Tech 2. Are any DTCs stored? - Go to
applicable
DTC table Go to Step 10
10 Review and record for Tech 2 data.
Is the action complete?
- Go to
Symptom
Diagnosis and Go to Basic Inspection
Procedure -
11 Replace the 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

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

5A-48 BRAKE CONTROL SYSTEM
DTC C0221 (Flash Code 21) Front Right Wheel Speed Sensor Short Circuit or
Circuit Open



RTW 75AMF001301

Step Action Value(s) Yes No
1 W ere the steps of the “Basic Diagnostic Flow Chart”
performed?
- Go to Step 2 Go to Basic
Diagnostic
Flow Chart
2 1. Check for a poor connection at the front right wheel speed sensor harness connector.
2. Check installation condition for front right wheel speed sensor.
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 3
3 1. Ignition “OFF”, disconnect the EHCU and front right
wheel speed sensor.
2. Check the circuit between EHCU and front right wheel speed sensor. (Circuit for an open, 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 4

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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-51
Step Action Value(s) Yes No
7 Check the front right wheel speed sensor. Refer to
"W heel Speed Sensor Inspection procedure"
W as a problem found? - Go to Step 10 Go to Step 8
8 Does the sensor rotor have missing tooth or saw- toothed? - Go to Step 14 Go to Step 9
9 1. Clear the DTC.
2. Test run the vehicle, and check the DTC. Is the DTC displayed repeatedly? - Go to Step 18 Go to Step 17
10 Is the wheel speed sensor damaged or saw-toothed?
- Go to Step 15 Go to Step 16
11 Adjust the preload of the wheel bearing.
Is the action complete? - Verify repair -
12 Repair or replace the front right speed sensor or the
sensor rotor.
Is the action complete? - Verify repair -
13 Repair the front right speed sensor or the sensor rotor.
Is the action complete? - Verify repair -
14 Replace the sensor rotor. Is the action complete? - Verify repair -
15 Replace the front right wheel speed sensor.
Is the action complete? - Verify repair -
16 Repair or replace the front right speed sensor
circuits.
Is the action complete? - Verify repair -
17 Check the connection btween the EHCU and the front right wheel speed sensor and repair as
necessary Refer to "Note on Intermittents".
Is the action complete? - Verify repair -
18 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

5A-52 BRAKE CONTROL SYSTEM
DTC C0225 (Flash Code 25) Front Left Wheel Speed Sensor Short Circuit or
Circuit Open



RTW 75AMF001301

Step Action Value(s) Yes No
1 W ere the steps of the “Basic Diagnostic Flow Chart”
performed?
- Go to Step 2 Go to Basic
Diagnostic
Flow Chart
2 1. Check for a poor connection at the front left wheel speed sensor harness connector.
2. Check installation condition for front left wheel speed sensor.
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 3
3 1. Ignition “OFF”, disconnect the EHCU and front left
wheel speed sensor.
2. Check the circuit between EHCU and front left wheel speed sensor. (Circuit for an open, 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 4

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ISUZU KB P190 2007

BRAKE CONTROL SYSTEM 5A-55
Step Action Value(s) Yes No
7 Check the front left wheel speed sensor. Refer to
"W heel Speed Sensor Inspection procedure"
W as a problem found? - Go to Step 10 Go to Step 8
8 Does the sensor rotor have missing tooth or saw- toothed? - Go to Step 14 Go to Step 9
9 1. Clear the DTC.
2. Test run the vehicle, and check the DTC. Is the DTC displayed repeatedly? - Go to Step 18 Go to Step 17
10 Is the wheel speed sensor damaged or saw-toothed?
- Go to Step 15 Go to Step 16
11 Adjust the preload of the wheel bearing.
Is the action complete? - Verify repair -
12 Repair or replace the front left speed sensor or the
sensor rotor.
Is the action complete? - Verify repair -
13 Repair the front left speed sensor or the sensor rotor. Is the action complete? - Verify repair -
14 Replace the sensor rotor.
Is the action complete? - Verify repair -
15 Replace the front left wheel speed sensor.
Is the action complete? - Verify repair -
16 Repair or replace the front left speed sensor circuits.
Is the action complete? - Verify repair -
17 Check the connection btween the EHCU and the
front left wheel speed sensor and repair as
necessary Refer to "Note on Intermittents".
Is the action complete? - Verify repair -
18 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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TO MODEL INDEX
ISUZU KB P190 2007