Code No.62: Driver’s
air bag module (squib) system (short-circuited to the
earth)
OPERATION
- The SRS-ECU judges how severe a collision is by detecting
signals from the
front impact sensors and the front air bag analog G-sensor. If
the impact is over a predetermined
level, the SRS-ECU outputs an ignition signal. At this time, if
the front air bag safing G-sensor
is on, the SRS air bag will inflate.
- The ignition signal is input to the air bag module via the clock
spring to inflate
the air bag.
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if
the driver’s air bag squib wire(s) are short-circuited
to the earth.
PROBABLE CAUSES
- Malfunction of the clock spring
- Damaged harness wires and connectors
- Short to the earth in the driver’s air bag module (squib)
harness
- Malfunction of the SRS-ECU
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STEP 1. Check the diagnosis code by connecting a dummy
resistor
(M.U.T.-III diagnosis code).
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(1)Disconnect the negative battery
terminal.
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(2)By sliding the A section (in the
figure) of air bag module connector C-312 in arrow
direction,
disconnect the connector.
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(3)Connect special tool dummy
resistor (MB991865) to special tool resistor harness
(MB991866).
(4)
| caution |
Do not insert a test probe
into the terminal from its front side directly
as the connector contact pressure may be
weakened.
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Insert special tool (MB991866) into clock spring
side air bag module connector C-312 by
backprobing.
(5)Connect the negative battery
terminal.
(6)Erase the diagnosis code memory, and check
the diagnosis code.
Q.
Is diagnosis code 62 out put?
 Go to Step
2.
 Replace
the driver’s air bag module (Refer to  ).
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STEP 2. Check the diagnosis code by connecting a dummy
resistor (M.U.T.-III
diagnosis code).
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(1)Disconnect the negative battery
terminal.
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(2)Disconnect the clock spring
connector C-309.
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(3)Connect special tool dummy
resistor (MB991865) to special tool resistor harness
(MB991866).
(4)
| caution |
Do not insert a test probe
into the
terminal from its front side directly as the
connector contact pressure may be
weakened.
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Insert special tool (MB991866) into clock spring
harness side connector C-309 (terminal
No.3 and 4) by backprobing.
(5)Connect the negative
battery terminal.
(6)Erase the diagnosis code memory, and
check the diagnosis code.
Q.
Is diagnosis code 62 set?
Go to Step
3.
Replace
the clock spring (Refer to ).
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STEP 3. Resistance measurement at the SRS-ECU connector
C-147.
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(1)Disconnect the negative battery
terminal.
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(2)Disconnect SRS-ECU connector
C-147.
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(3)
| danger |
To prevents the air bag from
deploying unintentionally, disconnect the clock
spring connector
C-309 to short the squib circuit.
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Disconnect the clock spring connector
C-309.
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(4)
| caution |
Do not insert a test probe
into the terminal from its front side directly
as the connector contact pressure may be
weakened.
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Check for continuity between C-147 harness side
connector terminals 11, 12 and body earth.
OK:
Open curcuit
Q.
Is the check result normal?
Go to Step
4.
Repair
the harness wires between SRS-ECU connector C-147 (terminal
No.11 and 12)
and clock spring connector C-309 (terminal No.3 and
4).
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STEP 4. Check whether the diagnosis code is
reset.
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Q.
Is diagnosis code 62 set?
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Replace the SRS-ECU
(Refer to ).
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An intermittent
malfunction is suspected (Refer to GROUP 00 -
How to
Use Troubleshooting/Inspection Service Points ).
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