21-1x

SRS DTC Troubleshooting: 21-1x, 21-2x (x can be 0 thru 9 or A thru F)

DTC 21-1x ("x" can be 0 thru 9 or A thru F): Open in the Driver's Seat Belt Tensioner

DTC 21-2x ("x" can be 0 thru 9 or A thru F): Increased Resistance in the Driver's Seat Belt Tensioner

Special Tools Required

- SRS inflator simulator 07SAZ-TB4011A
- SRS simulator lead F 07XAZ-SZ30100
NOTE: Before doing this troubleshooting procedure, review SRS Precautions and Procedures, Service and Repair General Troubleshooting Information, Reading and Clearing Diagnostic Trouble Codes and Battery Terminal Disconnection and Reconnection. Procedures

1. Clear the DTC memory. Reading and Clearing Diagnostic Trouble Codes

2. Turn the ignition switch to 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 21-1x or 21-2x indicated?
YES - Go to step 3.

NO - Intermittent failure, the system is OK at this time. Go to Troubleshooting Intermittent Failures. Reading and Clearing Diagnostic Trouble Codes If another DTC is indicated, troubleshoot the DTC.


3. Turn the ignition switch to LOCK (0).

4. Disconnect the negative cable from the battery, then wait at least 3 minutes.

5. Remove the B-pillar lower trim, Interior Trim Removal/Installation - B-Pillar Lower Trim then disconnect the left side wire harness 4P connector (A) from the driver's seat belt tensioner.

6. Connect the SRS inflator simulator (2 Ohms connectors) and simulator lead F to the left side wire harness.






7. Reconnect the negative cable to the battery.

8. Clear the DTC memory.

9. Read the DTC. Reading and Clearing Diagnostic Trouble Codes

Is DTC 21-1x or 21-2x indicated?
YES - Go to step 10.

NO - Open or increased resistance in the driver's seat belt tensioner; replace the driver's seat belt, Front Seat Belt Replacement then clear the DTC.


10. Turn the ignition switch to LOCK (0).

11. Disconnect the negative cable from the battery, then wait at least 3 minutes.

12. Disconnect SRS unit connector B (28P) from the SRS unit. Service and Repair

13. Measure the resistance between SRS unit connector B (28P) terminals No. 1 and No. 2. There should be 2.0-3.0 Ohms.

Is the resistance as specified?
YES - Faulty SRS unit or poor connection at SRS unit connector B (28P) and the SRS unit Check the connection; if the connection is OK, replace the SRS unit. SRS Unit Replacement

NO - Go to step 14.






14. Disconnect right side wire harness 16P connector C604 (A) from left side wire harness connector C604 (B).






15. Measure the resistance between left side wire harness 16P connector C604 terminals No. 4 and No. 5. There should be 2.0-3.0 Ohms.

Is the resistance as specified?
YES - Open or increased resistance in the right side wire harness; replace the right side wire harness, then clear the DTC.

NO - Open or increased resistance in the left side wire harness; replace the left side wire harness, then clear the DTC.