check engine ISUZU KB P190 2007 Workshop Owner's Manual

REAR AXLE 4B-45
TROUBLESHOOTING


Refer to this Section to quickly diagnose and repai
r
rear axle problems.
Each troubleshooting chart has three headings
arranged from left to right.
(1) Checkpoint
(2) Trouble Cause
(3) Countermeasure
This Section is divided into five sub-sections:
1. Abnormal Rear Axle Noise 1) Noise when the engine is driving the vehicle
2) Noise when the vehicle is coasting
3) Intermittent noise
4) Noise when the vehicle is turning
5) Constant noise
2. Vibration
3. Oil Leakage 1) Differential carrier leakage
2) Axle case leakage
3) Axle case to inside hub leakage
4) Axle case to inside brake drum leakage
4. Power Not Being Transmitted to the W heels (Propeller Shaft Operation is Normal)







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ISUZU KB P190 2007

4B-46 REAR AXLE
1. ABNORMAL REAR AXLE NOISE
1) Noise when the Engine is Driving the Vehicle

Checkpoint Trouble Cause Countermeasure

Replenish the gear oilInsufficient gear oil
NG
Differential side bearingAdjust the differential side
bearing preload
Replace the drive pinion
bearings
Adjust the drive pinion bearing
preload
Replace the gear oil
Loose differential side
bearings
W orn drive pinion bearings
Loose drive pinion bearings
W rong or poor grade gear oil
Drive pinion to ring gear
backlash
Drive pinion end play
Adjust the backlashToo much or too little backlash
Continued on the next page OK
OK
NG
NG
NG
NG
NG
OK
OK
Rear axle gear oil
Replace the differential side
bearingsW orn differential side bearings
NG


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ISUZU KB P190 2007

5A-24 BRAKE CONTROL SYSTEM
Computer System Service Precautions
The Anti-lock Brake System and Electronic Brake-force
Distribution interfaces directly with the Electronic
Hydraulic Control Unit (EHCU) which is a control
computer that is similar in some regards to the Engine
Control Module. These modules are designed to
withstand normal current draws associated with vehicle
operation. However, care must be taken to avoid
overloading any of the EHCU circuits. In testing for
opens or shorts, do not ground or apply voltage to any
of the circuits unless instructed to do so by the
appropriate diagnostic procedure. These circuits should
only be tested with a high impedance multimeter
5-8840-0366-0 or special tools as described in this
section. Power should never be removed or applied to
any control module with the ignition in the “ON” position.
Before removing or connecting battery cables, fuses or
connectors, always turn the ignition switch to the “OFF”
position.

General Service Precautions
The following are general precautions which should be
observed when servicing and diagnosing the Anti-lock
Brake System and/or other vehicle systems. Failure to
observe these precautions may result in Anti-lock Brake
System and Electronic Brake-force Distribution
damage.
• If welding work is to be performed on the vehicle using an electric arc welder, the EHCU and valve
block connectors should be disconnected before the
welding operation begins.
• The EHCU and valve block connectors should never be connected or disconnected with the
ignition “ON”.
Note:
• If only rear wheels are rotated using jacks or drum tester, the system will diagnose a speed sensor
malfunction and the “ABS and Brake” warning lamp
will illuminate. But actually no trouble exists. W hen
the DTC is not detected and the ABS and BRAKE
warning lamp is on, “How to erase code” is
performed and an ABS and BRAKE warning lamp
are off.
If the battery has been discharged
The engine may stall if the battery has been completely
discharged and the engine is started via jumper cables.
This is because the Anti-lock Brake System (ABS) and
Electronic Brake-force Distribution (EBD) System
requires a large quantity of electricity. In this case, wait
until the battery is recharged, or set the ABS and EBD
to a non-operative state by removing the fuse for the
ABS. After the battery has been recharged, stop the
engine and install the ABS fuse. Start the engine again,
and confirm that the ABS warning Lamp does not light.
Note on Intermittents
As with virtually any electronic system, it is difficult to
identify an intermittent failure. In such a case duplicating
the system malfunction during a test drive or a good
description of vehicle behavior from the customer may
be helpful in locating a “most likely” failed component or
circuit. The symptom diagnosis chart may also be
useful in isolating the failure. Most intermittent
problems are caused by faulty electrical connections or
wiring. W hen an intermittent failure is encountered,
check suspect circuits for:
• Suspected harness damage.
• Poor mating of connector halves or terminals not fully seated in the connector body (backed out).
• Improperly formed or damaged terminals.

Test Driving ABS Complaint Vehicles
If there has been an abnormality in the lighting pattern
of the “ABS” warning lamp, the fault can be located in
accordance with the “DIAGNOSIS BY “ABS” W ARNING
LAMP ILLUMINATION PATTERN”. Although such
problems can be detected by the driver as a vehicle
symptom, it is still necessary to perform a test drive
following the test procedure mentioned below, in order
to reproduce the symptom for problem diagnosis on a
symptom basis:
1. Start the engine and make sure that the “ABS” W /L
goes OFF. If the W /L remains ON, it means that
the Diagnostic Trouble Code (DTC) is stored.
Therefore, read the code and locate the fault.
Note: The DTC cannot be cleared if the vehicle speed
does not exceed about 10km/h (6mph) at DTC, even
though the repair operation is completed.
2. Start the vehicle and accelerate to about 30 km/h (19 mph) or more.
3. Slowly brake and stop the vehicle completely.
4. Then restart the vehicle and accelerate to about 40 km/h (25 mph) or more.
5. Brake at a time so as to actuate the ABS and stop the vehicle.
6. Be cautious of abnormality during the test. If the W /L is actuated while driving, read the DTC and
locate the fault.
7. If the abnormality is not reproduced by the test, make best efforts to reproduce the situation
reported by the customer.
8. If the abnormality has been detected, repair in accordance with the “SYMPTOM DIAGNOSIS”.
Note:
• Be sure to perform a test drive on a wide, even road
with light traffic.
• If an abnormality is detected, be sure to suspend the test and start trouble diagnosis at once.

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BRAKE CONTROL SYSTEM 5A-25
“ABS” Warning Lamp
W hen ABS and problems occur that actuate the “ABS”
warning lamp, the code corresponding to the problem is
stored in the EHCU. Only ordinary braking is available
when the ABS is deactivated. Even when the “ABS”
warning lamp is actuated, if the starter switch is set ON
after setting it OFF once, the EHCU checks up on the
entire system. If there is no abnormality, the EHCU
judges ABS to work correctly and the warning lamp is lit
normally, even though the problem code is stored.
NOTE: Illumination of the “ABS” warning lamp indicates
that anti-lock braking is no longer available. Power
assisted braking without anti-lock control is still
available.

Normal Operation
“ABS ” Warning Lamp
W hen the ignition is first moved from “OFF” to “RUN”,
the amber “ABS” warning lamp will turn “ON”. The
“ABS” warning lamp will turn “ON” during engine
starting and will usually stay “ON” for approximately
three seconds after the ignition switch is returned to the
“ON” position. The warning lamp should remain “OFF”
at all other times.

Brake (EBD) Warning Lamp


RTW 75ASH000101
Vehicles equipped with the EBD (Electronic Brake-force
Distribution) System have a “Brake” warning lamp on
the instrument panel.
If the ABS warning lamp and Brake warning lamp are
turned "ON", then EBD has failed. ( Parking brake
switch is "OFF")
In the following conditions, the EBD warning lamp is
"ON".
• Starter switch is "ON", engine "OFF". ( Parking brake switch is "OFF")
If engine is started, then EBD warning lamp is "OFF".
( Parking brake switch is "OFF")



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BRAKE CONTROL SYSTEM 5A-45
Braking Sound (From EHCU) Is Heard While Not Braking

Step Action Value(s) Yes No
1 Is this the first vehicle start after engine start?
- It is self
checking sound
Normal. Go to Step 2
2 Is vehicle speed at 15 km/h or 30 km/h?
- It is self
checking sound
Normal. Go to Step 3
3 Check for the following condition: • At the time of shift down or clutch operation.
• At the time of low road friction drive (ice or snow on road) or rough road drive.
• At the time of high-speed turn.
• At the time of passing curb.
• At the time of operating electrical equipment switches.
• At the time of racing the engine. Did it occur under any of the conditions above? - ABS may
sometimes be
actuated even when brake pedal is not applied. Go to Step 4
4 Is there play in each or any sensor/wheel speed sensor rotor? - Repair.
Go to Step 7 Go to Step 5
5 Damage or powdered iron sticking to each or any sensor/wheel speed sensor rotor? - Repair.
Go to Step 7 Go to Step 6
6 Is each sensor normal? Note: Check the EHCU type for specification, the
EHCU is replaced.
(Specification; 2W D or 4W D Model)

- Check
harness/
connector for suspected
disconnection
If no
disconnection is found,
replace EHCU
Go to Step 7 Repair.
Go to Step 7
7 Reconnect all components, ensure all components are properly mounted.
Is this step finished? - Repeat the
“Basic
diagnostic
flow chart” Go to Step 7


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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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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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5A-64 BRAKE CONTROL SYSTEM
DTC C0238 (Flash Code 38) Front Speed Sensor Correlation

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 the tire size of each wheels.
2. If the tire size is different, replace the tire.
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 3
3 1. Check for the gear ratio of a front axle differential gear and a rear axle differential gear.
2. If the gear ratio is different, repair the gear ratio.
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 4
4 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 5 Verify repair
5 1. Check for a poor connection at the wheel speed sensor harness connector.
2. Check installation condition for wheel speed sensor.
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 6
6 1. Check condition for sensor rotor.
2. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 7
7 1. Ignition “OFF” disconnect the EHCU and wheel
speed sensor.
2. Check the circuit between EHCU and wheel speed sensor. (short ground, or short to voltage)
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 8
8 1. Ignition “OFF”.
2. 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.
3. If a problem is found, repair as necessary. W as a problem found? - Verify repair Go to Step 9
9 1. Ignition “ON”, engine “OFF”.
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 10 Verify repair

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BRAKE CONTROL SYSTEM 5A-67
Step Action
Value(s) Yes No
3 1. Ignition “ON”, engine “OFF”.
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 4 Verify repair
4 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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BRAKE CONTROL SYSTEM 5A-69
Step Action
Value(s) Yes No
3 1. Ignition “ON”, engine “OFF”.
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 4 Verify repair
4 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