What this code means
B0001 can indicate an open circuit or increased resistance in the driver's airbag first inflator.
An open circuit is a break in an electrical path. Increased resistance means the path has more resistance than the procedure allows. For B0001, the path under investigation belongs to the driver's airbag first inflator. The diagnosis therefore needs to separate a problem associated with that component from a problem elsewhere in its circuit.
The driver's airbag first inflator, its connecting paths and the SRS unit are different possible fault areas. Naming the driver's airbag first inflator in the code does not make those possibilities interchangeable. The steps below narrow the fault area by changing a defined test condition and then checking the individual paths.
What the vehicle may do
- The driver's airbag first inflator circuit may be open.
- The first inflator circuit may have increased resistance.
Possible fault areas
- The driver's airbag may have a problem.
- The cable reel or its related wiring may have a problem.
- The SRS unit may have a problem.
The procedure moves through confirmation, an indirect component check and electrical-path checks. In the indirect check, the specified jumper connection is used exactly as described. The result determines whether the component or other related parts remain involved. The later measurements examine LA1+ and LA1- through the cable reel and the wiring between the cable reel and SRS unit.
Read the result criteria alongside the action that produces them. During the component check, a normal circuit-test result can point to a problem with the named component. During a wire check, an abnormal reading instead points to the checked path. These conclusions belong to different stages of the diagnosis.
Diagnostic path
Understand the stored condition
B0001 means Open or Increased Resistance in the Driver's Airbag First Inflator. The code points to a possible open circuit or increased resistance in that inflator circuit.
Understand the safety procedures first
Follow the SRS safety precautions before testing. Make sure you also understand the 12 volt battery terminal disconnection and reconnection procedures.
Check collision history
Before you start troubleshooting, find out whether the vehicle was in a collision. If it was, make sure all required components were replaced with new components. Check that those components have the correct part numbers and were installed properly.
Initial confirmation
Turn the vehicle to ON mode and wait for 10 seconds. You will repeat this confirmation check during the airbag test.
Check the driver's airbag circuit
Before you disconnect an SRS related connector, complete the 12 volt battery terminal disconnection procedure. Wait for at least 3 minutes before disconnecting the connector. Disconnect the driver's airbag first inflator connector (2P). Install a jumper wire between terminals No. 1 and No. 2 on that connector. Repeat the confirmation check by turning the vehicle to ON mode and waiting for 10 seconds. Check for DTC B0001-13. For a normal result, B0001-13 should not be indicated.
If the result is normal, there is a problem with the driver's airbag. If the result is abnormal, there is a problem with other related components.
For the component test, a normal result means the stated DTC B0001-13 is not indicated after the specified test connection and confirmation. The procedure associates that normal test result with a problem in the driver's airbag first inflator. An abnormal result follows the branch for other related components.
Here, the word normal refers to the response of the circuit test. It does not describe a direct resistance measurement of the driver's airbag first inflator. The wire checks that follow use their own resistance criteria and therefore answer a different question. This distinction is the key to reading the component and circuit branches correctly.
Check the cable reel LA1+ path
Before you disconnect any SRS related connector for the cable reel check, complete the 12 volt battery terminal disconnection procedure. Wait for at least 3 minutes. Make sure the driver's airbag first inflator connector (2P) and cable reel connector B (4P) are both disconnected. Check the cable reel paths LA1+ and LA1-. With IG Mode OFF, check LA1+ first.
- First probe: cable reel connector B (4P) male terminal 1.
- Other probe: driver's airbag first inflator connector (2P) female terminal 2.
- Normal reading: less than 1 ohm.
If the result is abnormal, there is a problem with the cable reel.
The cable-reel checks and the SRS-to-reel wiring checks examine different segments of the LA1 paths. At the reel segment, LA1+ runs from cable reel connector B terminal 1 to the airbag connector terminal 2; LA1- uses reel terminal 2 and airbag terminal 1. The later harness checks instead start at SRS unit connector A: terminal 3 is paired with reel terminal 1, and terminal 2 with reel terminal 2.
This explains why there are separate cable-reel and wiring stages even though the same path names appear. A normal result through the reel describes that segment. The measurements from the SRS unit connector describe the connecting harness segment. Keep the less-than-1-ohm criterion with each of the specified pairs.
Check the cable reel LA1- path
Keep IG Mode OFF and both connectors disconnected. Check the LA1- path next.
- First probe: cable reel connector B (4P) male terminal 2.
- Other probe: driver's airbag first inflator connector (2P) female terminal 1.
- Normal reading: less than 1 ohm.
If the result is abnormal, there is a problem with the cable reel.
Check the LA1+ wiring
Before you disconnect an SRS related connector for this wiring check, complete the 12 volt battery terminal disconnection procedure. Wait for at least 3 minutes. Disconnect SRS unit connector A (43P). Make sure cable reel connector B (4P) is also disconnected. Check the LA1+ and LA1- wiring for an open circuit. With IG Mode OFF, check LA1+ first.
- First probe: SRS unit connector A (43P) female terminal 3.
- Other probe: cable reel connector B (4P) female terminal 1.
- Normal reading: less than 1 ohm.
If the result is abnormal, there is a problem in the circuit.
Check the LA1- wiring
Keep IG Mode OFF and both connectors disconnected. Check the LA1- wiring next.
- First probe: SRS unit connector A (43P) female terminal 2.
- Other probe: cable reel connector B (4P) female terminal 2.
- Normal reading: less than 1 ohm.
If the result is abnormal, there is a problem in the circuit.
Evaluate the remaining SRS unit
If all the other checks give normal results, the SRS unit is the remaining cause.
Final check
The airbag test, cable reel checks, and wiring readings can help narrow the problem to the affected area.
Taken together, the results form a chain. The indirect component check establishes which branch to follow; the individual electrical checks identify an abnormal path; and the final SRS-unit conclusion depends on the earlier inspection items being normal. Keep the actual result beside the component or wire that was being checked. That makes the final decision traceable to the procedure, rather than to the wording of the stored code alone.
