DTC Troubleshooting: 21-3x

DTC 21-3x (21-30 to 21-39, 21-3A to 21-3F):
Short to Another Wire or Decreased Resistance in Left Side Seat Belt Tensioner


Special Tools Required
SRS inflator simulator (  07SAZ-TB4011A)

SRS simulator lead C (  07TAZ-SZ5011A)



1.Erase the DTC memory.

2.Turn the ignition switch ON (II), and check that the SRS indicator comes on for about 6 seconds and then goes off.

Does the SRS indicator stay on, and is DTC 21-3x indicated?


YES - Go to 3.


NO - Intermittent failure, system is OK at this time. Go to Troubleshooting Intermittent Failures. If another DTC is indicated, go to the DTC troubleshooting index.


3.Turn the ignition switch OFF. Disconnect the battery negative cable, and wait for 3 minutes.

4.Disconnect the driver's seat belt tensioner 2P connector (A) from the floor wire harness.

5.Connect the SRS inflator simulator (2 W connector) and the simulator lead C to the floor wire harness.

6.Reconnect the battery negative cable.

7.Erase the DTC memory.

8.Read the DTC.

Is DTC 21-3x indicated?


YES - Go to 9.


NO - Short in the left side seat belt tensioner; replace the left side seat belt.n


9.Turn the ignition switch OFF. Disconnect the battery negative cable, and wait for 3 minutes.

10.Disconnect the right side seat belt tensioner connector.

11.Disconnect SRS unit connector B (28P) from the SRS unit.

12.Disconnect the SRS inflator simulator from SRS simulator lead C.

13.Check resistance between the No. 1 and No. 2 terminals of SRS unit connector B (28P).
There should be an open circuit, or at least 1 MW.

Is the resistance as specified?


YES - Faulty SRS unit; replace the SRS unit.n


NO - Short in the floor wire harness; replace the floor wire harness.n