Isuzu N-Series. Service manual — part 1195
SRS CONTROL SYSTEM 9C-27
Data Display
Move the connector or harness by hand. If the display
changes from fix to release, connection of connector is
faulty, pin tip length is uneven, or open or short circuit in
the harness exists where you have moved. Therefore,
repair is necessary. When asterisk mark (*) is displayed
in place of numeric display; Problem of Tech 2.
If asterisk mark (*) is found any of the data, PCMCIA
card must be version upgraded.
Snapshot (Graph Plotting)
• The snapshot can record the data list menu and
plot a graph.
• Utilizing this mode, reproduce and record the con-
ditions claimed by the customer to identify the en-
gine data fault.
• The stored data can be replayed with a domestic
power supply.
Programming
• Before replacing SRS control unit, be sure to
check/save the vehicle information. After replace-
ment, input it.
List of Diagnostic Trouble Code
Caution:
• Trouble codes No. 21, 25, 71 cannot be cleared.
• Code No. 12 indicates that the system is normal.
F0 : Read the DTC in the order of priority.
F1 : Clear the DTC.
Application menu
N9A0075E
Trouble code
No.
Item to be detected
“SRS” warning lamp ON
14
Connector is half-connected
ON
21
Resistance of SRS airbag deployment circuit is large
ON
22
Resistance of SRS airbag deployment circuit is small
ON
24
SRS airbag deployment circuit is shorted to ground
ON
25
SRS airbag deployment circuit is shorted to ignition voltage
ON
26
SRS airbag deployment circuit is open
ON
51
SRS airbag deployment current had output
ON
53
Specific trouble when SRS airbag deployment current had output
ON
54
Deployment output by onboard deployment system communica-
tion
55
Vehicle type error
ON
61
Warning lamp circuit trouble
ON
63
Power supply voltage failure
ON
71
SRS control unit internal trouble
ON
9C-28 SRS CONTROL SYSTEM
DTC: 14 Connector is Half-connected
Outline
Description of Circuit
Turn the starter switch to “ON”. SRS control unit checks
the condition of half-connection detection terminal.
Condition when DTC is set
The half-connection detection terminals “a” and “b” are
not connected via connector.
Action to be taken
SRS control unit turns the warning lamp ON and set the
code 14.
Condition when DTC is cleared
Connector is connected completely, and the half-con-
nected terminal has continuity.
B
ACC
ON
ST
STARTER SWITCH
METER
AIRBAG
SRS CONTROL UNIT
DATA LINK CONNECTOR
16 15 14 13 12 11 10 9
8 7 6 5 4 3 2 1
0.5
B
0.5
GY
0.5
SB
0.5
GY
0.5
SB
16
4
19
15
18
7
8
20
6
5
0.85B
0.85B
0.5
B/R
0.5
B/R
0.5
W/R
0.5
B/R
0.5
B/R
0.5
W/R
0.5
B
1.25
B
2L
3
B/Y
2
14
3W/L
8B
3W/L
40A
KEY SW
10A
SRS
AIRBAG
SRS COIL
ASSEMBLY
1
2
2
1
0.5
Y
0.5
Y/B
3
10A
METER
0.5
B/Y
18
OFF
N9A0086E
SRS CONTROL SYSTEM 9C-29
Step
Action
Value
YES
NO
1
Has the “SRS system check” been per-
formed?
—
Go to “SRS sys-
tem check”.
2
1. Turn the starter switch to OFF.
2. Check if the connector of the SRS control
unit is connected securely.
Is the connector of the SRS control unit con-
nected securely?
—
Insert the SRS
control unit con-
nector
securely.Go to
3
Temporarily disconnect the SRS control unit
connector, and check the half-connection
detection terminal for faulty such as bent and
dirt.
Is there any fault?
—
Replace either of
the SRS control
unit or SRS har-
ness whichever is
faulty.Go to Step4
Go to Chart A
SRS control unit
function check.
4
1. Reconnect all the parts, and check that
those are installed properly.
2. Clear the DTC.
Is this step completed?
—
Check the repair.
9C-30 SRS CONTROL SYSTEM
DTC: 21 Resistance of SRS Airbag Deployment Circuit is Large
Outline
Description of Circuit
Turn the starter switch to “ON”. SRS control unit per-
forms the tests to diagnose critical function fault inside
the SRS control unit. Upon completion of the tests, when
the results are pass, “Ignition” voltage and deployment
circuit voltage will be measured to check they are within
the normal range. Then, the SRS control unit performs
“Resistance measurement test”. SRS control unit flows
a minimal known amount of current between the termi-
nals “7” and “8”, and measures the voltage difference
between the two, and then calculates the combined re-
sistance in the SRS airbag, SRS coil assembly, SRS
airbag deployment circuit, and connector terminal con-
tact point.
Condition when DTC is Set
When combined resistance of SRS airbag, SRS coil as-
sembly, SRS airbag deployment circuit, and connector
terminal contact point exceeds the specified value. This
test is performed constantly after elapse of six seconds
from the “Ignition” voltage exceeds 10V.
Action to be Taken
SRS control unit turns the “SRS” warning lamp ON and
set the DTC 21.
Condition when DTC is Cleared
When the resistance goes back to less than specified
value.
Description of DTC Chart Test
Numbers below indicate step numbers in the diagnostic
chart.
2. This test is to check if the location of function fault is
in the SRS control unit.
3. This test is to check if the 2-pole connector (yellow)
located in the lower portion of steering column is proper-
ly connected.
4. This test is to check the 2-pole connector (yellow) ter-
minal located in the lower portion of steering column for
secure contact and/or corrosion.
5. This test is to check if the location of function fault is
up to the 2-pole connector (yellow) located in the lower
portion of steering column.
6. This test is to check the function fault is caused by
high resistance value in the wiring.
7. This test is to check if the location of function fault is
in the SRS coil assembly or SRS airbag.
SRS CONTROL UNIT
AIRBAG
SRS COIL
ASSEMBLY
1
2
2
1
0.5
Y
0.5
Y/B
8
7
N9A0076E
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст