DTC (Diagnostic Trouble Codes)

The self-diagnostic function of the SRS unit allows it to locate the causes of system problems and store this information in memory. For easier troubleshooting, this data can be retrieved with the HDS via the data link circuit.

When you turn the vehicle to the ON mode, the SRS indicator should come on. If it goes off after 6 seconds, the system is normal and is not currently detecting any problems.
If there is a problem, the system locates and defines the problem, stores this information in the memory, and turns on the SRS indicator. The data remains in the memory even if the vehicle is turned to the OFF (LOCK) mode or the 12 volt battery is disconnected.
The data is stored in memory as a diagnostic trouble code (DTC).
DTCs are either latching or resetting depending on the malfunction. With resetting DTCs, the SRS indicator goes off the next time the vehicle is turned to the ON mode, and the system is normal, but the DTC is still stored. With latching DTCs, the SRS indicator does not turn off until the malfunction is repaired and the DTC is cleared.
When you connect the HDS to the data link connector (DLC), you can retrieve a more detailed DTC in the HDS "SRS" menu.
After reading and recording the DTC, go to the troubleshooting procedure for that code.

Precautions

Make sure the 12 volt battery is fully charged. If the 12 volt battery is dead or low, electrical measurement values may not be correct.
Use only a digital multimeter to check the system. Make sure its output is 10 mA (0.01 A) or less when switched to the smallest value in the ohmmeter range. A tester with a higher output could damage the airbag circuit or cause accidental airbag deployment and possible injury.
Whenever the vehicle is turned to the ON mode, or the vehicle is in the OFF (LOCK) mode for less than 3 minutes, be careful not to bump the SRS unit; the system could falsely interpret an impact or rollover, deploying airbags in response and cause damage or injuries.
Before removing the dashboard wire harness or floor wire harness, disconnect the driver's airbag inflator connector, the front passenger's airbag inflator connector, both side airbag inflator connectors, both side curtain airbag inflator connectors, and both front seat belt tensioner connectors.