Code No.B1472: Seat Belt Pre-tensioner Squib (LH) (Earth Side)
Short-circuited
| caution |
If diagnosis code B1472 is set in the SRS-ECU, always
diagnose the CAN main bus line.
|
OPERATION
The SRS-ECU judges how severe a collision is by
detecting signals from the front impact sensors and the front air bag analogue
G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an
ignition signal. At this time, if the front air bag safing G-sensor is on, the
pre-tensioner will deploy.
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if the
seat belt pre-tensioner (LH) (squib) wire(s) are short-circuited to the
earth.
PROBABLE CAUSES
- Damaged wiring harnesses or connectors
- Short to the earth in the seat belt pre-tensioner (LH) (squib)
harness
- Malfunction of the SRS-ECU
|
|
STEP 1. M.U.T.-III CAN bus diagnostics
|
|
|
Use the M.U.T.-III to diagnose the CAN bus
lines.
|
|
|
Q.
Is the check result normal?
|
|
|
 Go to Step 2.
|
|
|
|
|
|
 Repair
the CAN bus line (Refer to GROUP 54D, Diagnosis  ).
|
|
|
|
|
|
STEP 2. Check whether the diagnosis code is reset.
|
|
|
Check again if the diagnosis code is
set.
|
|
|
(1)Erase the diagnosis code.
|
|
|
(2)Ignition: "LOCK" (OFF) position to "ON"
|
|
|
(3)On completion, check that the diagnosis code is not
reset.
|
|
|
Q.
Is the diagnosis code set?
|
|
|
Go to Step 3.
|
|
|
|
|
|
There
is an intermittent malfunction such as poor engaged connector(s) or open
circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
|
|
|
|
|
|
STEP 3. Check the seat belt pre-tensioner.
|
|
|
(1)Disconnect seat belt pre-tensioner (LH) connector
E-16.
|
|
(2)Connect special tool dummy resistor
(MB991865) to special tool resistor harness (MB991866).
(3)Connect
special tool MB991866 to the E-16 harness side connector.
(4)Connect the
negative battery terminal.
(5)Erase the diagnosis code from memory, and
check the diagnosis code.
Q.
Is diagnosis code B1472 set?
Go to Step 4.
Replace the seat belt with
pre-tensioner (LH) (Refer to ).
|
|
|
STEP 4. Check the seat belt pre-tensioner (LH) circuit. Resistance
measurement at the SRS-ECU connector D-25.
|
|
|
(1)Disconnect the negative battery terminal.
|
|
|
(2)Disconnect SRS-ECU connector D-25.
|
|
|
(3)Disconnect seat belt pre-tensioner (LH) connector
E-16.
|
|
|
(4)
| caution |
Do not insert a test probe into the terminal from
its front side directly, as the connector contact pressure may be
weakened.
|
Check for continuity between D-25 harness side connector terminals
7, 8 and body earth.
OK: Open circuit
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 5.
|
|
|
|
|
|
Repair
the harness wires between SRS-ECU connector D-25 (terminal No.7 and 8) and
seat belt pre-tensioner (LH) connector E-16 (terminal No.1 and 2).
|
|
|
|
|
|
STEP 5. Check whether the diagnosis code is reset.
|
|
|
Q.
Is diagnosis code B1472 set?
|
|
|
Replace the SRS-ECU (Refer to ).
|
|
|
|
|
|
An
intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with
Intermittent Malfunction ).
|
|
|
|