Description of On-Board Diagnostics

A DRB scan tool is required for diagnosis of the airbag system. See Body Control Module / Testing and Inspection / Procedures.
Testing and Inspection

16-Way Data Link Connector - Typical:

1. Connect the DRB scan tool to the 16-way data link wire harness connector. The connector is located on the driver side lower edge of the instrument panel, inboard of the steering column.
2. Turn the ignition switch to the On position. Exit the vehicle with the DRB. Be certain that the DRB contains the latest version of the proper DRB software.
3. Using the DRB, read and record the active Diagnostic Trouble Code (DTC) data.
4. Read and record any stored DTC data.
5. See the proper Diagnostic Procedures if any DTC is found in Step 3 or Step 4.
6. After completing the necessary repairs, try to erase the stored DTC data. If any problems remain, the stored DTC data will not erase. See the proper Diagnostic Procedures for the procedures to diagnose any stored DTC that will not erase.
7. With the ignition switch still in the On position, check to be certain that nobody is in the vehicle.
8. From outside of the vehicle (away from the airbags in case of an accidental deployment) turn the ignition switch to the Off position for about ten seconds, and then back to the On position. Observe the airbag indicator lamp in the instrument cluster. It should light for six to eight seconds, and then go out. This indicates that the airbag system is functioning normally.

NOTE:
- If the airbag indicator lamp fails to light, or lights and stays on, there is an airbag system malfunction. See the proper Diagnostic Procedures to diagnose the problem.

- All extended cab models (club cab or quad cab) are equipped with a structural seat, which uses an electronic structural seat belt control system to control the latching and unlatching of the integral seat belt retractors. The structural seat belt control system MUST be tested to ensure proper operation following the service of any airbag system component. Refer to Seat Belt Control System Test Mode in the Seat Belt Control Systems for the test procedure.

Airbag Diagnostic Trouble Codes
Airbag diagnostic trouble codes consist of active and stored codes. If more than one code exists, diagnostic priority should be give to the active codes.

Active diagnostic trouble codes for the airbag system are not permanent and will change the moment the reason for the code is corrected. In certain test procedures, diagnostic trouble codes are used as a diagnostic tool.

Active Codes
The code becomes active as soon as the malfunction is detected or key-OFF, whichever occurs first. An active trouble code indicates an on-going malfunction. This means that the defect is currently there every time the airbag control module checks that circuit/function. It is impossible to erase an active code; active codes automatically erase by themselves when the reason for the code has been corrected.

With the exception of the warning lamp trouble codes or malfunctions, when a malfunction is detected, the airbag lamp remains lit for a minimum of 12 seconds or as long as the malfunction is present.

The seat belt lamp replaces the airbag lamp if the airbag lamp is Defective. The seat belt lamp pulses ON and OFF 30 times if the airbag warning lamp is defective.

Stored Codes
Airbag codes are automatically stored in the ACM's memory as soon as the malfunction is detected. The exception is the "Loss of Ignition Run Only" code which is an active code only.

A "stored" code indicates there was an active code present at some time. However, the code currently may not be present as an active code, although another active code could be.

When a trouble code occurs, the airbag warning lamp illuminates for 12 seconds minimum (even if the problem existed for less than 12 seconds). The code is stored, along with the time in minutes it was active, and the number of times the ignition has been cycled since the problem was last detected.

The minimum time shown for any code will be one minute, even if the code was actually present for less than one minute. Thus, the time shown for a code that was present for two minutes 13 seconds, for example, would be three minutes.

If a malfunction is detected a diagnostic trouble code is stored and will remain stored as long as the malfunction exists. When and if the malfunction ceases to exist, an ignition cycle count will be initiated for that code. If the ignition cycle count reaches 100 without a reoccurrence of the same malfunction, the diagnostic trouble code is erased and that ignition cycle counter is reset to zero. If the malfunction reoccurs before the count reaches 100, then the ignition cycle counter will be reset and the diagnostic trouble code will continue to be a stored code.

If a malfunction is not active while performing a diagnostic test procedure, the active code diagnostic test will not locate the source of the problem. In this case, the stored code can indicate an area to inspect.

If no obvious problems are found, erase stored codes, and with the ignition "ON" wiggle the wire harness and connectors, rotate the steering wheel from stop to stop. Recheck for codes periodically as you work through the system. This procedure may uncover a malfunction that is difficult to locate.

Airbag Trouble Codes
The Airbag Control Module may report any of the following diagnostic trouble codes.

For the following codes, replace the Airbag Control Module (ACM) even if set intermittently:
- ACM ACCELEROMETER - FIRING CAPACITOR LOW
- AECM OUTPUT DRIVER CIRCUIT OPEN - LOGIC CAPACITOR LOW
- AECM INTERNAL DIAGNOSTIC
- CODE # 1 - SAFING SENSOR SHORTED
- WARNING LAMP DRIVER ERROR

For these codes refer to the appropriate diagnostic procedure:
- Cluster Message Mismatch
- Driver Squib Circuit Open
- Driver Squib Circuit Shorted
- Driver Squib Circuit Shorted to Battery
- Driver Squib Circuit Shorted to Ground
- Loss of Ignition Run Only
- Loss of Ignition Run/Start
- No Cluster CCD Message
- No CCD Communication
- Missing or Invalid VIN
- Passenger Squib Circuit Open
- Passenger Squib Circuit Shorted
- Passenger Squib Circuit Shorted to Battery
- Passenger Squib Circuit Shorted to Ground
- VIN Mismatch
- Warning Lamp Bulb or Driver