Isuzu N-Series. Manual — part 261
5A4-18 ABS/ASR
How to Clear Diagnosis Trouble Code (DTC)
DTCs stored in the EHCU will not be erased automati-
cally upon repair. Clear the DTCs using either of the fol-
lowing procedure:
1. Input the brake switch ON/OFF signal for six times
within three seconds while self-diagnosis result is
being output.
2. Use Tech 2 to clear.
CAUTION:
• After performing the DTC clear procedure, ensure
that it is cleared.
• If the step 1 does not work, perform with the step2.
Precautions During Diagnosis
At general baintenance
Adhere the following precautions when servicing and di-
agnosing of the ABS/ASR and other vehicle control sys-
tems.
• When performing electric-arc welding on the vehi-
cle, disconnect the EHCU connector before start-
ing welding work.
• Do not connect/disconnect the EHCU connector
when the starter switch is ON.
• The EHCU is a non-disassembled part. Do not
loosen the bolts and plugs of the EHCU.
• Be especially careful not to allow dirt, dust or me-
tallic powder to get into the hydraulic circuit during
checking and servicing the brake components.
• When only rear wheels are rotated using dram
tester or jack-upped for inspection, the ABS judges
it as sensor fault and illuminates the ABS warning
lamp. This indicates no fault in the system. Erase
the ABS diagnosis code after repair. Turn the start-
er switch to ON again, to make sure that the ABS
warning lamp does not come on.
When servicing computer system
Extreme care is required to avoid overcurrent to the
EHCU circuit. Do not ground to or apply voltage to the
EHCU without careful consideration while checking
open/short circuit. Use only the circuit tester having high
internal resistance or the special tool described in this
section to check those circuit. Do not connect/discon-
nect the power supply to the EHCU when the starter
switch is ON. Be sure to turn the starter switch to OFF
before disconnecting/connecting the battery cable, the
fuse, or the connector.
When replacing EHCU
The EHCU body fault rarely occurs, but more cases are
falsely identified as EHCU trouble, as it happened to be
corrected when replacing the EHCU but the fact is most-
ly secondary failure caused by the harness-side trouble
(such as short circuit) or undetectable cause due to in-
termittent trouble. Therefore, before replacing the EH-
CU, check if overcurrent is applied to the EHCU as well
as improper connection of the connectors.
Intermittent trouble
Intermittent troubles are mostly caused by temporally
disconnection of the harnesses and connectors. If a
trouble occurs, check the related circuit in the following
procedure.
1. Check for misconnection of the connector. Also
check for improper connection of the connector ter-
minal.
2. Check for deformation and damage of the terminal.
If deformed or damaged, correct and reconnect it
securely.
3. Simulated open circuit is also suspected. Check
the circuit by shaking the harness in a degree that
does not damage the harness.
Test run of vehicle with ABS problem
Trouble cause of the problem appeared as ABS warning
lamp illumination, can be identified with “Diagnostic pro-
cedure with illumination pattern”. However for the prob-
lem that can solely be identified by the driver as trouble
N5A2017E
ABS/ASR 5A4-19
symptoms, the following procedure is necessary to iden-
tify the trouble cause by reproducing the trouble symp-
tom with test run the vehicle.
1. Start the engine, and make sure that the ABS
warning lamp goes off. (If the lamp does not go off,
read the DTC and identify the trouble part.)
2. Slowly start the vehicle and run at 30 km/h (19
mph) or more for three minutes, then apply the
brake to stop the vehicle completely. Start the ve-
hicle again and accelerate to 30 km/h (19 mph) or
more. Repeat this operation a least three times.
3. Next, start the vehicle and accelerate to 40 km/h
(25 mph) or more, and then abruptly apply the
brake to activate the ABS, till stop the vehicle.
4. If the warning lamp comes on during the test run,
check the DTC and inspect the vehicle according
to the DTC. If no DTC appeared, or the warning
light does not come on, reproduce the condition of
the trouble occurrence claimed by the customer as
much as possible.
5. If DTC appeared or trouble symptom is found, per-
form the appropriate inspection according to the di-
agnostic procedure.
Check after repair
Upon completion of repair, turn the starter switch to OFF
and then start the engine to make sure each lamp goes
off. Next, run the vehicle at 30 km/h (19 mph) or more for
1 minute, and check that the lamp does not come on.
Brake basic inspection
Ground check
Step
Action
Value
YES
NO
1
Is the brake fluid level correct?
—
Replenish fluid.
2
Is fluid leaked?
—
Repair. Go to
3
Does the vacuum booster operate normally?
—
Repair. Go to
4
Is the brake pad and rotor normal?
—
Repair. Go to
5
Install all the components, and check that
those are installed properly.
Is this step completed?
—
End.
Step
Action
Value
YES
NO
1
Are all the ground point related to ABS OK?
—
Repair. Go to
2
Install all the components, and check that
those are installed properly.
Is this step completed?
—
End.
5A4-20 ABS/ASR
Diagnostic basic flow
Function Check
EHCU Connector Pin Arrangement
Step
Action
Value
YES
NO
1
1. Complaint from the customer
2. Interview to the customer.
3. Perform the basic inspection. (Refer to
“Brake basic inspection”.)
Is Tech 2 required?
—
2
Check DTC.
Is DTC appeared?
—
3
Check DTC (with warning lamp illumination
pattern).
Is DTC appeared?
—
4
Test run the vehicle.
Does the warning lamp come on?
—
Refer to “List of
trouble symp-
5
1. Repair the trouble part.
2. Clear the DTC.
3. Check the ABS warning lamp for illumina-
tion pattern with the ignition switch ON.
4. Test run the vehicle.
Is the trouble appeared again?
—
Repeat the “Diag-
nostic basic flow”
if the trouble
appeared again
(with trouble
symptom or DTC).
6
1. Install all the components, and check that
those are installed properly.
2. Clear the DTC.
Is this step completed?
—
End.
N5A2018E
ABS/ASR 5A4-21
Terminal
Mark
Signal name
Wire color
1
VALVE GND
ECU system ground (body ground 0V)
BLK
2
VALVE+B
Solenoid valve power supply
RED
3
IG-KEY
ECU system power supply
BLK/YEL
4
DIAG
Diagnosis entry
WHT/GRN
5
SW; ASR OFF
ASR cut switch (ASR only)
BLU
6
ABS W/L
ABS warning lamp output
WHT/VIOLET
7
NC
Not available
—
8
NC
Not available
—
9
NC
Not available
—
10
FR SIG
FR wheel speed signal (magnetic pickup sensor)
PNK
11
FR GND
FR wheel speed signal GND
BLU
12
RR GND
RR wheel speed signal GND
WHT
13
NC
Not available
—
14
CAN-H
CAN Hi input
BLU/WHT
15
CAN-L
CAN Lo input
BLU
16
BRK SW
Brake switch input signal
GRN
17
NC
Not available
—
18
NC
Not available
—
19
NC
Not available
—
20
NC
Not available
—
21
RR SIG
RR wheel speed signal
RED
22
RL SIG
RL wheel speed signal
BLU
23
MOTOR GND
Motor ground (body ground 0V)
BLK
24
MOTOR+B
Motor power supply
RED
25
NC
Not available
—
26
CAN-H
CAN Hi input
BLU/WHT
27
CAN-L
CAN Lo input
BLU
28
NC
Not available
—
29
ALDL
J1850 Class 2 communication
WHT/BLK
30
ASR W/L
ASR warning lamp output (ASR only)
WHT/BLU
31
NC
Not available
—
32
FL SIG
FL wheel speed signal (magnetic pickup sensor)
VIOLET
33
FL GND
FL wheel speed signal GND
RED/BLK
34
RL GND
RL wheel speed signal GND
YEL
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст