For 1990-2009 cars

The body control module (MALL) provides a set of internal service diagnostic features. These features assist the technician in troubleshooting electrical short conditions that may affect the module. If an electrical short occurs during vehicle operation, the MALL module stores 1 or more codes. These codes are known as history codes. These history codes may be accessed by entering the MALL module diagnostic mode. After providing the history codes, the MALL module enters the Input/Output (I/O) Mode. The I/O Mode provides the technician with the ability to verify that the inputs to the MALL module are functioning properly.

### Entering the Diagnostic Mode

In order to enter the body control module (MALL) diagnostic mode perform the following steps:

1. Place the ignition switch in the ON position.
2. Press and hold the power door unlock switch.
3. Within 20 seconds of pressing the unlock switch, cycle the headlamps 6 times.
4. Release the power door unlock switch.

### Exiting the Diagnostic Mode

In order to exit the diagnostic mode, perform 1 of the following actions:

• | Turn the ignition switch to the OFF position.

• | Accelerate the vehicle above 13 km/h (8 mph).

### History Codes

Upon entering the diagnostic mode, the MALL module provides audible feedback in the form of bongs; the number of bongs represents the stored history code number. The FASTEN BELTS indicator flashes with each bong. In the following chart, the history code is listed with the corresponding short circuit condition:

History Code | Short Condition
--- | ---
1 | FASTEN BELTS indicator (SBTELL) circuit
2 | Battery protection (PBATT) circuit
3 | Courtesy lamps (CTSY) circuit

The MALL module cycles through the stored history code(s) 3 times. For example, if a short condition occurs on the FASTEN BELTS indicator circuit and battery protection circuit, 1 bong sounds for the FASTEN BELTS indicator circuit, followed by 2 bongs for the battery protection circuit. A 2 second pause occurs before the history codes repeat. If no history codes exist, the MALL module immediately enters the input/output mode.

The history codes may be erased by holding down the power door unlock switch for 4 seconds.

### Input/Output (I/O) Mode

While in the input/output (I/O) mode, the technician may test each input to the MALL module by activating/deactivating its input device. For example, the door latch switch, interior lamp switch, seatbelt switch, etc. The MALL module provides feedback on each input transition in the form of a single bong along with a simultaneous flash of the FASTEN BELTS indicator.

Test the battery protection (PBATT) input/output by cycling the interior lamps switch. For example, the first cycle (OFF, ON, OFF) deactivates the PBATT output (interior lamps off). Cycling the interior lamp switch once again activates the PBATT output (interior lamps on). The cycle repeats afterwards.

### I/O Mode Feedback for Vehicles Equipped with Keyless Entry

The MALL module electrical schematic differs between vehicles that have keyless entry and vehicles without keyless entry. For vehicles that are equipped with keyless entry, the audible feedback is different when activating any of the following items:

• | The power door lock switch

• | The transaxle gear selector

• | The keyless entry unlock, using the keyless entry transmitter

The following table describes the feedback for this case:

Input | MALL Module Audible Feedback | Reason
--- | --- | ---
Power Door Lock Switch | 2 Bongs | 350 ms pulse from the remote function actuator (RFA) module
PARK Transition | 2 Bongs | 350 ms pulse from the RFA module due to the gear selector power door lock/unlock feature
Remote Unlock (Using Transmitter) | 2 Bongs | 350 ms pulse from the RFA module due to remote interior illumination feature

For Pontiac vehicles, no bongs occur when shifting into the PARK position. This is due to the ignition-OFF door unlock feature.

The following table lists the MALL inputs and outputs that should be evaluated during the input/output (I/O) mode:

Function/Feature | Test by Activating, Deactivating
--- | ---
Auxiliary Chime | Park Brake and/or Instrument Cluster Warning
Interior Lamps | Interior Lamp Switches
Dome Lamps | Dome Lamp Switches
Door Latch (Jamb) Switches | Left and Right Front Door Latch (Jamb) Switches
Power Door Locks | Power Door Lock and Unlock Switches
Automatic Door Lock and Unlock | Gear Selector
Battery Protection | Interior Lamp Switch
Lamps On Reminder Chime | Headlamp Switch
Fasten Seatbelts Chime and FASTEN BELTS indicator | Driver's Seatbelt Switch
Turn Signal On Reminder Chime | Left and Right Turn Signal
Trunk Lid Ajar Lamp | Trunk Lid Latch Switch