Description of On-Board Diagnostics: Diagnostic Trouble Codes

DIAGNOSTIC TROUBLE CODES
Each diagnostic trouble code is diagnosed by following a specific testing procedure. The diagnostic test procedures contain step-by-step instructions for determining the cause of trouble codes. It is not necessary to perform all of the tests to diagnose an individual code.

Always begin by reading the diagnostic trouble codes using the DRB. This procedure begins with TEST 1A - Testing System Function. This will direct you to the specific test(s) that must be performed. If more than one code exists, diagnostic priority should be given to the active code(s).

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
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.

STORED CODES

AB, AS, and JA bodies only - An airbag trouble code becomes active and stored as soon as it is detected with the exception of the Loss of Ignition Run Only code, which is an active code only.

All other bodies - Airbag codes are automatically stored in the ACM's memory when the ignition is turned off with the exception of 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 AIR BAG 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 that same malfunction, that 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. 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 these codes, replace the Airbag Control Module (ACM):
- AECM Accelerometer
- AECM Internal Diagnostic 1
- AECM Internal Diagnostic 2
- AECM Output Driver
- AECM Stored Energy
- Incorrect AECM
- Internal Diagnostic 1
- Internal Diagnostic 2
- Internal Diagnostic 3
- Internal Diagnostic 4
- Low Stored Energy Driver
- Low Stored Energy Passenger
- Safing Sensor Open
- Safing Sensor Shorted

For these codes, refer to the appropriate diagnostic procedure:
- AECM & Cluster CCD Message Mismatch
- Driver Squib Circuit Open
- Driver Squib Circuit Shorted
- Driver Squib Term Shorted to Battery
- Driver Squib Term Shorted to Ground
- Front Sensor Circuit Shorted
- Loss of Ignition Run Only
- Loss of Ignition Run/Start
- No CCD Communication
- No Cluster CCD Bus Message
- No Body Controller CCD Bus Message
- One Front Sensor Circuit Open
- Passenger Squib Circuit Open
- Passenger Squib Circuit Shorted
- Pass Squib Term Shorted to Battery
- Pass Squib Term Shorted to Ground
- Pressure Switch Circuit Open/Shorted
- Seat Belt Pretensioner Circuit Open
- Seat Belt Pretensioner Circuit Shorted to Battery
- Seat Belt Pretensioner Circuit Shorted to Ground
- Seat Belt Pretensioner Circuit Shorted
- Two Front Sensors Circuit Open
- Warning Lamp Circuit Open
- Warning Lamp Circuit Shorted
- Warning Lamp Interface # 1
- Warning Lamp Interface # 2

INTERMITTENT TROUBLE CODES
If the following codes are being set intermittently, the airbag control module should be replaced:
- AECM Accelerometer
- AECM Internal Diagnostic 1
- AECM Internal Diagnostic 2
- AECM Output Driver
- AECM Stored Energy
- Internal Diagnostic 1
- Internal Diagnostic 2
- Internal Diagnostic 3
- Internal Diagnostic 4
- Internal Lamp Driver
- Low Stored Energy Driver
- Low Stored Energy Passenger
- Safing Sensor Open
- Safing Sensor Shorted

If any other intermittent codes are stored, check for the following:
- loose or corroded connections
- damaged components
- damaged wiring

If no obvious problems are found, erase stored codes, and with the key on, wiggle the wire harness and connectors. Recheck for codes periodically as you work through the system. This procedure may uncover a malfunction that is difficult to locate.