HELP!! Air suspension on my Navigator

[driller]

More info...

Inspection and Verification


Verify the customer concern.
NOTE: If the door ajar indicator is illuminated when all doors, the liftgate and the liftgate glass are closed, the air suspension will not work correctly. Repair the door ajar indicator; refer to Section 413-09 .

Visually inspect for obvious signs of mechanical and electrical damage.


Visual Inspection Chart Mechanical Electrical
Restricted suspension movement
Excessive vehicle load
Cut, severed or crimped air line(s)
Unmounted height sensor
Damaged air spring(s)
Open fuses:
Central junction box (CJB) Fuse 4 (15A), 6 (5A) and 20 (5A)
Battery junction box (BJB) Fuse 109 (50A)
Loose, corroded or disconnected connectors
Air suspension switch is in the OFF position
Damaged solenoid valve(s)



If the inspection reveals an obvious concern that is readily repaired, correct the concern before continuing with Inspection and Verification.
If the concern remains after the inspection, use NGS Tester connected to the data link connector (DLC) to retrieve continuous diagnostic trouble codes (DTCs) and to execute On-Demand Self-Test diagnostics for the air suspension control module.
If the On-Demand Self-Test is passed and no DTCs are retrieved, go to Symptom Chart to continue diagnostics.
If DTCs are retrieved, go to Air Suspension Control Module Diagnostic Trouble Code (DTC) Index in this section.
If the air suspension control module cannot be accessed by the NGS Tester, go to Pinpoint Test A.

On-Demand Self-Test


Verify that the following conditions are met before performing the On-Demand Self-Test.

All doors, liftgate and liftgate glass must be closed.
The transmission is in PARK.
The brake pedal position (BPP) switch is not pressed during the test and the parking brake is not set.
The accelerator pedal is not pressed during this test.
Fulfill the conditions before starting self-test.
Install a battery charger for the On-Demand Self-Test to prevent battery drain.
Run the air suspension On-Demand Self-Test.
Record all listed DTCs.
Retrieve stored DTCs.
Diagnose any On-Demand Self-Test DTCs first.
Retest and clear DTCs after repair.
Air Suspension Control Module Diagnostic Trouble Code (DTC) Index

Air Suspension Control Module Diagnostic Trouble Code (DTC) Index DTCs Description Source Action
B1318 Battery Voltage Low Air Suspension Control Module GO to Pinpoint Test C .
B1342 Air Suspension Control Module Air Suspension Control Module INSTALL a new air suspension control module; REFER to Module—Air Suspension Control . SET the front ride height; REFER to Air Suspension Initialization (Clear DTC B2140). CLEAR the DTCs. REPEAT the self-test.
B1485 Brake Pedal Input Circuit Battery Short Air Suspension Control Module RERUN On-Demand Self-Test. MAKE SURE that the brake pedal is not pressed. If DTC is returned again, REPAIR brake pedal position (BPP) circuitry.
B1566 Door Ajar Circuit Short to Ground Air Suspension Control Module GO to Pinpoint Test D .
B2140 Initialization Failure (Vehicle Ride Height Not Programmed) Air Suspension Control Module REFER to Air Suspension Initialization (Clear DTC B2140).
C1439 Vehicle Acceleration EEC-V Circuit Failure Air Suspension Control Module GO to Pinpoint Test E .
C1724 Air Suspension Height Sensor Power Circuit Failure Air Suspension Control Module GO to Pinpoint Test F .
C1726 Air Suspension Rear Pneumatic Failure Air Suspension Control Module GO to Pinpoint Test G .
C1760 Air Suspension Rear Height Sensor High Signal Circuit Failure Air Suspension Control Module GO to Pinpoint Test H .
C1770 Air Suspension Vent Solenoid Output Circuit Failure Air Suspension Control Module GO to Pinpoint Test I .
C1790 Air Suspension LR Air Spring Solenoid Output Circuit Failure Air Suspension Control Module GO to Pinpoint Test J .
C1795 Air Suspension RR Air Spring Solenoid Output Circuit Failure Air Suspension Control Module GO to Pinpoint Test K .
C1830 Air Suspension Compressor Relay Circuit Failure Air Suspension Control Module GO to Pinpoint Test L .
C1917 Steering Electronic Variable Orifice (EVO) Out-of-Range Fault Air Suspension Control Module REPAIR EVO steering system. REFER to Section 211-00 .



Air Suspension Control Module Parameter Identification (PID) Index

Air Suspension Control Module Parameter Identification (PID) Index PID Description Expected Values
4WDLOW Generic Electronic Module 4WD Low Signal to Air Suspension Control Module ON, OFF
4WDSYS Signal From Electronic Shift Relay & Diode Module to Air Suspension Control Module YES, NO
ACC_SIG Acceleration Signal to the Air Suspension Control Module notPRE, PRESNT
AS_COMP Air Suspension Compressor Status ON, OFF
AS_GATE Air Suspension Front Solenoid Gate Valve Status (4WAS Only) ON, OFF
AS_VENT Air Suspension Vent Solenoid Valve Status ON, OFF
ASLRSOL or LR_SOL Air Suspension LR Spring Solenoid Valve Status ON, OFF
ASRRSOL or RR_SOL Air Suspension RR Spring Solenoid Valve Status ON, OFF
BOO_AS Brake Pedal Position (BPP) Switch Input to the Air Suspension Control Module ON, OFF
DOOR_AS Door Ajar Input to the Air Suspension Control Module CLOSED, AJAR
F_FILL Air Suspension Front Fill Solenoid Valve Status (4WAS Only) ON, OFF
FHGTSEN Value of Front Air Suspension Height Sensor (4WAS Only) DC voltage value
IGN_AS Ignition RUN/START Input to the Air Suspension Control Module notRUN, RUN
PK/N_SW Park/Neutral Switch Input to the Air Suspension Control Module notP/N, P/N
R_FILL Air Suspension Rear Fill Solenoid Valve Status (4WAS Only) ON, OFF
RHGTSEN Value of Rear Air Suspension Height Sensor DC voltage value
STEER_A Electronic Steering Sensor A Signal to the Air Suspension Control Module HIGH, LOW
STEER_B Electronic Steering Sensor B Signal to the Air Suspension Control Module HIGH, LOW
VBAT_AS Battery Voltage Value to the Air Suspension Control Module DC voltage value
VSS_AS or VSS_ARC Display Vehicle Speed Sensor Input to the Air Suspension Control Module VSS signal in kph or mph
LC_4WDL Latch Seeing 4WD Low Signal to the Air Suspension Control Module CHANGD/NOCHAG
LC_ACC Latch Seeing Acceleration Signal to the Air Suspension Control Module CHANGD/NOCHAG
LC_BOO Latch Seeing Brake Pedal Position (BPP) Switch Signal to the Air Suspension Control Module CHANGD/NOCHAG
LC_DOOR Latch Seeing Door Ajar Signal to the Air Suspension Control Module CHANGD/NOCHAG
LC_IGN Latch Seeing Ignition RUN/START Signal to the Air Suspension Control Module CHANGD/NOCHAG
LC_PK/N Latch Seeing Park/Neutral Switch Input to the Air Suspension Control Module CHANGD/NOCHAG
LC_VSS Latch Seeing Vehicle Speed Sensor (VSS) Signal Input to the Air Suspension Control Module (If Greater Than 56 kph [35 mph]) CHANGD/NOCHAG
LCSTR_A Latch Seeing Electronic Steering Sensor A Signal to the Air Suspension Control Module CHANGD/NOCHAG
LCSTR_B Latch Seeing Electronic Steering Sensor B Signal to the Air Suspension Control Module CHANGD/NOCHAG
OPSTRAT Status of the Air Suspension Operational Strategy (4 Corner or Rear Only System) 4WAS/2WAS


Air Suspension Control Module Active Command Index

Air Suspension Control Module Active Command Index Active Command Display Action
AIR SUSPENSION CONTROL LIFT FRNT ON, OFF (4WAS Only)
VENT FRNT ON, OFF (4WAS Only)
LIFT REAR ON, OFF
VENT REAR ON, OFF (4WAS Only)
COMPRESSR ON, OFF
VENT ON, OFF
FRNT FILL ON, OFF (4WAS Only)
GATEVALVE ON, OFF (4WAS Only)
REAR FILL ON, OFF (4WAS Only)
LR AIRSP ON, OFF
RR AIRSP ON, OFF
LAMP NORM ON, OFF



Symptom Chart

NOTE: Refer to Wiring Diagrams for connector numbers stated in the Pinpoint Tests.

Symptom Chart Condition Possible Sources Action
No communication with the air suspension control module
CJB Fuse 4 (15A), 6 (5A) and 20 (5A).
Circuitry.
Air suspension control module.
Air suspension switch.
GO to Pinpoint Test A .

Unable to enter self-test
Air suspension control module
GO to Pinpoint Test B .

4x2 vehicle returns front air suspension component DTC
Circuitry.
REPAIR Circuit 900 (BK) for possible intermittent short to ground.

Vehicle changes height with the door open
Circuitry.
Air suspension control module.
GO to Pinpoint Test D .

Vehicle raises and/or lowers too slowly
Circuitry.
Rear pneumatic fault.
Air compressor assembly.
Air suspension control module.
GO to Pinpoint Test I .

Uneven vehicle height
Circuitry.
Rear pneumatic fault.
Air compressor assembly.
Air suspension control module.
GO to Pinpoint Test I .

The air compressor continuously cycles with the ignition switch in the Off position and no DTC is set
Circuitry.
Air suspension control module.
Air suspension relay.
GO to Pinpoint Test M .

The air suspension system is inoperative
Circuitry.
GO to Pinpoint Test N .

Excessive air compressor operation
Circuitry.
GO to Pinpoint Test N .

Harsh or bouncy ride
Circuitry.
GO to Pinpoint Test N .

Ride height changes unexpectedly
Circuitry.
GO to Pinpoint Test N .

The air suspension system operates with the air suspension switch in the OFF position
Circuitry.
Switch.
Air suspension control module.
GO to Pinpoint Test O .

Excessive air compressor noise
Silencer.
Wire harness.
Mounting bracket.
GO to Pinpoint Test P .

The compressor is inoperative
BJB Fuse 109 (50A).
Air compressor assembly.
Circuitry.
Air suspension relay.
GO to Pinpoint Test Q .

[sleeper]

Beautiful info, JP. Mine is the 4WAS - I'd love to convert to rear only, because the front suspension design is hacked together crap - still has torsion bars, just like the RAS models, but it adds an air spring to the crappy OEM underdamped shock. They suck. I think one is leaking, but it's not throwing a light. OEM is the only replacement, and I want bilstiens.

So it sounds like I need to buy bilstiens for a RAS Navi, pick up some torsion bars off of a RAS Navi (should have higher rate than the 4WAS suspension), and figure out which wires to cut.

Soo... I need wiring diagrams. Pinouts of the connectors, at least, just like we have on the site for the "Kale" mod.

"NOTE: The 4WAS air suspension control module is used for the RAS system. The internal processor recognizes external circuitry to determine if it is installed in a 4WAS or a RAS equipped vehicle. " - good stuff! Looks like I can just cut some wires and my computer will still work. I still want to be able to do manual control like I can with my Mark, though. It'll be handy when hooking up my trailer.