Code No.B1604
Seat belt pre-tensioner (driver’s side) (squib) system (open circuit of
squib circuit)
caution |
If diagnosis code B1604 is
set in the SRS-ECU, be sure to diagnose the CAN bus line.
|
|
Only when the frontal impact exceeding the
threshold is simultaneously detected (turned
ON) by the front impact sensor as well as by the analogue G-sensor and
safing G-sensor in SRS-ECU,
the electric current is supplied from SRS-ECU to the seat belt
pre-tensioner (squib).
|
|
The code is set when the open circuit occurs to
the SRS-ECU seat belt pre-tensioner (driver’s
side) (squib) circuit.
|
|
- Poor contact of connector
- Open circuit to seat belt pre-tensioner (driver’s side) (squib)
circuit
- Malfunction of SRS-ECU
|
|
STEP 1. M.U.T.-III CAN bus diagnostics.
|
|
Use 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 54C - Troubleshooting ).
|
|
|
|
STEP 2. Check whether the diagnosis code is set again.
|
|
(1)Connect the negative battery terminal.
|
|
(2)After erasing the diagnosis code memory, check the
diagnosis code again.
|
|
(3)Disconnect the negative battery terminal.
|
|
Q.
Is diagnosis code No. B1604 set?
|
|
Go to Step 3.
|
|
|
|
Intermittent malfunction (Refer to
GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction ).
|
|
|
|
STEP 3. Diagnosis check by dummy resistor connection.
|
|
(1)Check that the negative battery terminal is disconnected.
If the negative battery
terminal is connected, disconnect it.
|
![](../../../img/52/ACE02069AC00ENG.png)
|
(2)Use the flat-tipped screwdriver to pull out
the locking button of harness side connector.
After releasing the lock, disconnect the seat belt pre-tensioner
(driver’s side) harness
side connector.
|
![](../../../img/52/AC301553DP00ENG.png)
|
(3)Connect special tool dummy resistor
(MB991865) to special tool resistor harness (MB991884). (4)Connect the
special tool resistor harness to the seat belt pre-tensioner
(driver’s
side) harness side connector. (5)Connect the negative battery
terminal. (6)After erasing the diagnosis code memory, check the
diagnosis code again. (7)Disconnect the negative battery
terminal.
Q.
Is diagnosis code No. B1604 set?
Go to Step 4.
Replace the seat belt with
pre-tensioner (driver’s side) (Refer to ).
|
|
STEP 4. Resistance measurement at the SRS-ECU connector and the seat
belt pre-tensioner (driver’s side) connector.
|
|
(1)Check that the negative battery terminal is disconnected.
If the negative battery
terminal is connected, disconnect it.
|
|
(2)Disconnect the SRS-ECU connector.
|
![](../../../img/52/ACE02069AC00ENG.png)
|
(3)
danger |
To release the SRS-ECU connector short spring in
the
following operations, disconnect this seat belt pre-tensioner connector,
and keep the squib
circuit shorted.
|
Use the flat-tipped screwdriver to pull out the locking button of
harness side connector.
After releasing the lock, disconnect the seat belt pre-tensioner
(driver’s side) harness
side connector.
|
![](../../../img/52/ACE02056AB00ENG.png)
|
(4)
caution |
The short spring may not be released due to the
insufficient insertion. Therefore, insert
the insulator for 4 mm or more.
|
Insert an insulator (width: 3 mm, thickness: 0.5 mm) such as cable
tie between the PTA+,
PTA- line and the short spring, and release the short spring. (5)
caution |
Do not insert a probe directly into the terminal of
pre-tensioner (driver’s
side) connector harness side connector from the connector front side as
the connector contact
pressure may be weakened.
|
Take the measurements below at the SRS-ECU connector and seat belt
pre-tensioner connector
harness side connectors.
- Continuity PTD- line between SRS-ECU connector and seat
belt pre-tensioner (driver’s side) connector
- Continuity PTD+ line between SRS-ECU connector and seat belt
pre-tensioner
(driver’s side) connector
OK: Continuity (less than 2 Ω)
Q.
Is the check result normal?
Go to Step 5.
Repair the wiring harness PTD+,
PTD- line between the SRS-ECU connector
and the seat belt pre-tensioner (driver’s side)
connector.
|
|
STEP 5. Check whether the diagnosis code is set again.
|
|
Q.
Is diagnosis code No. B1604 set?
|
|
Replace SRS-ECU (Refer to ).
|
|
|
|
Intermittent malfunction (Refer to
GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction ).
|
|
|