Diagnostic Instructions

The control module has the capability of performing either a series of diagnostic tests on the air suspension system or to fill the front and/or rear air springs.  Specific instructions for using the air fill capability are in Removal and Installation.

Instructions for entering diagnostics and test description are as follows:

1. Turn on the air suspension switch. Diagnostic pigtail is to be ungrounded.
    
2. Install battery charger to reduce battery.
    
3. Leave the driver's door open, with all other doors shut. Cycle the ignition from the OFF position to RUN position.  Hold in the RUN position for a minimum of five seconds then return to the OFF position.
    
4. Change the diagnostic pigtail from an ungrounded state to a grounded state by attaching a lead from the diagnostic pigtail to vehicle ground.  The pigtail must remain grounded during the diagnostic sequence.
    
5. Turn the ignition switch to the RUN position (Do not start vehicle). The warning lamp will blink continuously at a rate of 1.8 blinks per second to indicate diagnostics has been entered and is ready.
    
6. Close, then open the driver’s door once to initiate Test 1.  The warning lamp will blink once, pause, blink, pause, etc. until the next test is started.
    
7. Each successive transition from the door closed to door open will cause the module to advance to the next step in the test sequence.  The warning lamp will blink the current test number.

Terminating Diagnostic

Diagnostic may be terminated and the module returned to the normal operational mode at any time by cycling the ignition, actuating the brake, or ungrounding the diagnostic pigtail.

Test Description

Test 1

Rear Suspension

Test 2
RH Front Suspension

Test 3
LH Front Suspension

Test 4
Compressor is cycled on/off at 0.25 Hz.
The compressor is limited to cycling a maximum of 50 times.

Test 5
Vent solenoid is cycled open/closed
at 1 Hz.

The following Steps occur in each of the first three Tests:

1. Raise the (rear, RH front, LH front) of the vehicle for 15 seconds. Continue raising vehicle for an additional 15 seconds (30 seconds total maximum) or until a “Vehicle High” signal, or an illegal sensor read is received from the (rear, RH front, LH front) sensor.

2. Lower the (rear, RH front, LH front) of the vehicle for 15 seconds. Continue raising vehicle for an additional 15 seconds (30 seconds total maximum) or until a “Vehicle High” signal, or an illegal sensor read is received from the (rear, RH front, LH front) sensor.

3. Raise the (rear, RH front, LH front) of the vehicle for 15 seconds. Continue raising vehicle for an additional 15 seconds (30 seconds total maximum) or until a “Vehicle High” signal, or an illegal sensor read is received from the (rear, RH front, LH front) sensor.

   If the expected signal is not received within the 30 second limit, the test will stop and the warning lamp will turn on continuously.  Also, if an illegal sensor reading is received, the test will stop and the warning lamp will flash rapidly.
   
   The failed test may then be repeated by closing/opening the door or the next test may be initiated by closing/opening the door twice within 15 seconds.

Allow time for vehicle to return to normal height, then turn the ignition switch to the OFF position and disconnect.  Remove the diagnostic ground lead in the luggage compartment.