Code No. B1610: Seat
belt pre-tensioner (passenger’s side) (squib) system (open circuit of
squib circuit)
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If diagnosis code No.
B1610 is set in the SRS-ECU, be sure to diagnose the CAN bus line.
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OPERATION
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 in SRS-ECU,
the electric
current is supplied from SRS-ECU to the seat belt pre-tensioner (squib).
TROUBLE JUDGEMENT
The code is set when the open circuit occurs to
the SRS-ECU seat belt pre-tensioner (passenger’s
side) (squib) circuit.
PROBABLE CAUSES
- Damaged wiring harness and connector
- Open circuit to seat belt pre-tensioner (passenger’s side) (squib)
circuit
- Malfunction of SRS-ECU
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STEP 1. M.U.T.-III CAN bus diagnostics.
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Use M.U.T.-III to diagnose the CAN bus
lines.
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Q.
Is the check result normal?
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 Go to Step 2.
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 Repair
the CAN bus line (Refer to GROUP 54C -
Troubleshooting  ).
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STEP 2. Check whether the diagnosis code is set again.
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(1)Connect the negative battery terminal.
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(2)After erasing the diagnosis code memory, check the
diagnosis code again.
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(3)Disconnect the negative battery terminal.
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Q.
Is diagnosis code No. B1610 set?
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Go to Step 3.
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Intermittent malfunction.
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STEP 3. Diagnosis check by dummy resistor connection.
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(1)Check that the negative battery terminal is disconnected.
If the negative battery
terminal is connected, disconnect it.
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(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
(passenger’s side) harness
side connector.
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(3)Connect special tool dummy resistor
(MB991865) to special tool resistor harness (MB991884).
(4)Connect
special tool resistor harness to the seat belt pre-tensioner
(passenger’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. B1610 set?
Go to Step 4.
Replace the seat belt with
pre-tensioner (passenger’s side).
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STEP 4. Resistance measurement at the SRS-ECU connector and the seat
belt pre-tensioner (passenger’s side) connector.
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(1)Check that the negative battery terminal is disconnected.
If the negative battery
terminal is connected, disconnect it.
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(2)Disconnect the SRS-ECU connector.
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(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.
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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
(passenger’s side) harness
side connector.
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(4)
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The short spring may not be released due to the
insufficient insertion. Therefore, insert
the insulator for 4 mm or more.
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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.
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(5)Connect special tool resistor harness
(MB991884) to the removed seat belt pre-tensioner
(passenger’s side) harness side connector.
(6)Take the
measurements below at the resistor harness and SRS-ECU harness side
connector.
- Continuity PTA+
line between SRS-ECU connector
and resistor harness connector
- Continuity PTA- line between SRS-ECU connector to resistor harness
connector
OK: Continuity (less than 2 Ω)
Q.
Is the check result normal?
Go to Step 5.
Repair the wiring harness PTA+,
PTA- line between the SRS-ECU connector
and the seat belt pre-tensioner (passenger’s side)
connector.
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STEP 5. Check whether the diagnosis code is set again.
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Q.
Is diagnosis code No. B1610 set?
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Replace SRS-ECU.
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Intermittent malfunction.
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