Airbag System

AIRBAG SYSTEM
The Airbag system is designed to provide increased driver and passenger protection if the vehicle is involved in a front-end collision. The airbag system is designed to be used in conjunction with the seat belt system.

Whenever the ignition switch is turned to the Run or Start position, the ACM performs a warning indicator bulb-check via a PCI bus request to the instrument cluster to illuminate the Airbag Warning Indicator. The indicator remains illuminated for 6 - 8 seconds, and then turns off. If the indicator remains off the ACM has checked the system and found it to be free of discernable malfunctions.

The ACM monitors critical input and output circuits within the airbag system, ensuring the circuits are operating properly. Some circuits are tested continuously; other circuits are tested only under certain circumstances. The ACM provides diagnostic information about the airbag system to the technician through the DRBIII via the PCI bus.

The deceleration of g-forces resulting from the impact of a front end collision causes the electronic sensor inside of the ACM to be triggered. This causes the inflators to be actuated, thus deploying the airbag(s). The total time between determining to deploy and deflation of the airbag is 1/10th of one second (100 ms).

The 2003 Jeep Wrangler (TJ) may be equipped with a Passenger Airbag (PAB) On/Off Switch. This switch has an ACM-controlled light that will illuminate when the switch is in the Off position.

Use the test procedures to diagnose the cause of any customer complaint regarding the Airbag Warning Indicator (located in the instrument cluster), such as:

- Airbag warning indicator does not illuminate at any time
- Airbag warning indicator is illuminated at all times

Passenger Airbag On/Off Switch
Vehicles without rear seats will be equipped with a Passenger Airbag (PAB) On/Off Switch. The PAB On/Off Switch allows the vehicle operator to turn the passenger airbag function On or Off.

The Off indicator in the PAB On/Off Switch will be illuminated for 2 seconds whenever the ignition is transitioned to the Run position as a bulb check. The Off indicator will remain illuminated when the PAB On/Off Switch is turned to the Off position.

The PAB On/Off Switch assembly is mounted in the center of the instrument panel below the radio, this allows the Off indicator to be visible to both front seat occupants.

WARNING: ALWAYS CHECK THE PASSENGER AIRBAG ON/OFF SWITCH POSITION BEFORE DRIVING THE VEHICLE. A SWITCH IN THE WRONG POSITION INCREASES THE RISK OF SERIOUS INJURY OR DEATH IN A COLLISION.

To operate the Passenger Airbag On/Off Switch, insert the ignition key into the PAB On/Off Switch keyway, push the key in to release the internal plunger, and rotate switch to the desired position. The spring-loaded locking plunger prevents the user from leaving the key in the switch. The key will be automatically ejected from the switch when inward force is not applied. The ignition key is the only key or object that should ever be inserted into the PAB On/Off Switch.

NOTE: Do not turn the Passenger Airbag On/Off Switch while the ignition is in the Run position.

The ACM continuously monitors the resistance of the Passenger Airbag On/Off Switch circuits to identify the switch position and to provide switch circuit diagnostics.

- ON Position: Passenger Airbag On/Off Switch resistance = 175 - 190 ohms
- OFF Position: Passenger Airbag On/Off Switch resistance = 820 - 870 ohms

If the ACM detects that the PAB On/Off Switch circuits are open, shorted to ground, or shorted to battery voltage, it will set Active and Stored DTC's. When a DTC is detected by the ACM, it will transmit a PCI bus message to the Instrument Cluster to illuminate the Airbag warning indicator. Whenever the Airbag warning indicator is illuminated, the ACM should be the first module to be interrogated.

If after replacing the ACM, any of the following codes are active, the ACM must be re-configured to match the vehicle equipment:

- MODULE NOT CONFIGURED FOR PAB OFF SWITCH
- PASSENGER AIRBAG ON/OFF SWITCH CIRCUIT OPEN
- PASSENGER AIRBAG ON/OFF SWITCH INDICATOR CIRCUIT OPEN

To properly configure the ACM, using the DRBIII, select Miscellaneous from the Airbag system menu and follow instructions.

WARNING: IGNORING THE AIRBAG WARNING INDICATOR IN THE INSTRUMENT CLUSTER COULD MEAN THE PASSENGER AIRBAG ON/OFF SWITCH IS NOT FUNCTIONAL AND THE PASSENGER AIRBAG MAY DEPLOY IF AN IMPACT OCCURS. IF THE AIRBAG WARNING INDICATOR ILLUMINATES, WHILE DRIVING, THE AIRBAG ON - OFF SWITCH WILL REMAIN FUNCTIONAL FOR THAT KEY CYCLE. IF THE AIRBAG WARNING INDICATOR ILLUMINATES AGAIN AT THE NEXT IGNITION ON AND STAYS ILLUMINATED FOR MORE THAN 6 - 8 SECONDS, THE ACM WILL DEFAULT TO PASSENGER AIRBAG ON. IF THE AIRBAG WARNING INDICATOR BULB TEST OR IF THE OFF INDICATOR DOES NOT ILLUMINATE WITH THE SWITCH IN THE OFF POSITION THE PASSENGER AIRBAG MAY DEPLOY IF AN IMPACT OCCURS.

SPECIAL TOOLS
Some airbag diagnostic tests use special tools, the 8310 and 8443 airbag load tools for testing squib circuits, The load tools contain fixed resistive loads, jumpers, and adapters. The fixed loads are connected to cables and are mounted in a storage case.

The cables can be directly connected to some airbag system connectors. Jumpers are used to convert the load tool cable connectors to other airbag system connectors. The adapters are connected to the module harness connector to open shorting clips and to protect the connector terminal during testing.

When using the load tool, follow all of the safety procedures in the service information for disconnecting airbag system components. Inspect the wiring, connector, and terminals for damage or misalignment.

Substitute the airbag load tool in place of a Driver or Passenger airbag, curtain airbag, clockspring, or seat belt tensioner, (use a jumper if needed). Then follow all of the safety procedures in the service information for connecting airbag system components.

Read the module active DTC's. If the module reports NO ACTIVE DTC'S, the defective component has been removed from the system and should be replaced. If the DTC is still active, continue this process until all of the components in the circuit have been tested.

Then disconnect the module connector and connect the matching adapter to the module connector. With all airbags disconnected and adapter installed, the squib circuits can be tested for open and shorted conditions.

DIAGNOSTIC TROUBLE CODES
Airbag diagnostic trouble codes (DTC) consist of active and stored codes. If more than one DTC exists, diagnostic priority should be given to the active code(s). Each DTC is diagnosed by following a specific testing procedure. The diagnostic test procedures contain step-by-step instructions for determining the cause of the DTC. It is not necessary to perform all of the tests to diagnose an individual DTC.

Always begin by reading the DTC's using the DRBIII. If more than one code exists, diagnostic priority should be given to active code(s).

Active DTC's for the airbag system are not permanent and will change the moment the cause of the code is corrected. In certain test procedures DTC's are used as a diagnostic tool.

Active Codes
An active trouble code indicates an on-going malfunction. This indicates that the defect is currently active every time the ACM checks the particular circuit or function. It is impossible to erase an active code; active codes automatically erase themselves when the cause for the code has been corrected.

With the exception of the warning indicator trouble codes or malfunctions, when a malfunction has been detected by the ACM, the Airbag warning indicator is illuminated for a minimum of 12 seconds, or as long as the malfunction is present.

Stored Codes
Airbag codes are automatically stored in the ACM memory as soon as the malfunction is detected, with the exception of the Loss Of Ignition Run-Only code, which is an active code only. A stored code indicates that 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 may be.

When a trouble code occurs, the Airbag warning indicator illuminates for 12 seconds minimum, (even if the condition existed for less than 12 seconds). Stored codes display the time in minutes that the code was active, and the number of times that the ignition has been cycled since the active code 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 not active while performing a diagnostic test, the active code diagnostic test will not locate the source or the condition. In this case, the stored code can indicate an area to inspect. The following procedure may uncover a malfunction that is difficult to locate:

WARNING: MAINTAIN A SAFE DISTANCE FROM ALL AIRBAGS WHILE PERFORMING THE FOLLOWING INSPECTION:

If no obvious problems are found:
- Erase the stored codes
- Place the ignition in the Run position
- Wiggle the wire harness and connectors
- Rotate the steering wheel from stop to stop
- Recheck for active codes periodically as you work through the system.