DTC 21-8x ("x" can be 0 thru 9 or A thru F): Short to Power in 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 (see PRECAUTIONS AND PROCEDURES ) and General Troubleshooting Information (see DTC (DIAGNOSTIC TROUBLE CODES) ).

Clear the DTC memory (see CLEAR THE DTC MEMORY WITH THE HDS ).
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 21-8x indicated?

YES -Go to step 3.

NO -Intermittent failure, system is OK at this time. Go to TROUBLESHOOTING INTERMITTENT FAILURES . If another DTC is indicated, troubleshoot the DTC.
Turn the ignition switch OFF. Disconnect the negative cable from the battery, then wait for 3 minutes.
Disconnect the driver's seat belt tensioner 4P connector (A) from the floor wire harness.

Fig 1: Identifying Driver's Seat Belt Tensioner 4P Connector

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Connect the SRS inflator simulator (2 Ω connectors) and simulator lead F to the floor wire harness.
Reconnect the negative cable to the battery.
Clear the DTC memory.
Read the DTC (see DTC (DIAGNOSTIC TROUBLE CODES) ).
Is DTC 21-8x indicated?

YES -Go to step 9.

NO -Short to power in the driver's seat belt tensioner; replace the driver's seat belt (see FRONT SEAT BELT REPLACEMENT ).
Turn the ignition switch OFF. Disconnect the negative cable from the battery, then wait for 3 minutes.
Disconnect the front passenger's seat belt tensioner connector (see step 6 ).
Disconnect SRS unit connector B (28P) from the SRS unit (see step 7 ).
Disconnect the simulator lead from the floor wire harness.
Reconnect the negative cable to the battery.
Turn the ignition switch ON (II).
Measure the voltage between the No. 1 terminal of SRS unit connector B (28P) and body ground, and between the No. 2 terminal and body ground. There should be 0.5 V or less.

Fig 2: Measuring Voltage Between No. 1 Terminal Of SRS Unit Connector B (28P) And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the voltage 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 (see SRS UNIT REPLACEMENT ).

NO -Short to power in the floor wire harness; replace the floor wire harness.