Mechanics

AIR SUSPENSION PROBLEM

1997 Cadillac El Dorado • V8 FWD Automatic • 146,000 miles

Hi I recently bought a 97 eldorodo. For some reason the car sitting low. Dont no where to start by checking it. Can u help with some info on what to do by fixing the problem. Thank u
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Brown 1
December 7, 2010.




TROUBLE SHOOTING
If ELC system is not properly functioning and no codes are set, check the following.
Check rear position sensors for disconnected or damaged links.
If air compressor operates continuously, check for a short to voltage in ELC air compressor motor circuit (Dark Green wire), or for ELC compressor relay stuck closed.
If air compressor will not turn on, check for ELC compressor relay stuck open.
If air compressor does not operate at full performance, check for a weak battery.
If vehicle rear is high and no road-sensing suspension codes are set, check mechanical portion of exhaust solenoid valve.
If ride is rough, cause may be lack of residual pressure in rear shock absorbers. Perform ELC system leak/performance test. See ELC SYSTEM LEAK/PERFORMANCE TEST.
If circuit breakers are tripped, check for no head relief, a faulty air compressor motor, or short to ground in ELC air compressor motor ground circuit (Black wire). If air compressor motor is faulty, replace ELC air compressor assembly.
REMOVAL & INSTALLATION
CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

AIR COMPRESSOR
Removal
Raise and support vehicle. Remove and support exhaust system from rear hangers. Clean air compressor surrounding area to prevent dirt from entering ELC system. Disconnect air line from air drier. Disconnect air line and 2 clips from air compressor bracket.
Remove intake air filter and air line from vehicle and air compressor. Disconnect air compressor electrical connector. Remove air compressor bracket-to-suspension mounting bolts. Remove air compressor and bracket from rear of vehicle as an assembly. Remove bracket from air compressor.

ELC SYSTEM LEAK/PERFORMANCE TEST
If ELC air compressor assembly and air lines have been replaced, go to step 7). If ELC air compressor assembly and air lines have not been replaced, go to next step.
Raise and support vehicle. Check air lines from air drier to both rear shock absorbers. Check air line connection at air drier. If air lines are damaged or disconnected, go to step 13). If air lines are okay, go to next step.
Squeeze middle of left rear shock absorber sleeve. If sleeve can be slightly compressed, go to step 5). If sleeve can not be compressed, go to next step.
Turn ignition off. Connect scan tool to Data Link Connector (DLC) under left side of instrument panel. Turn ignition on, with engine off. Using scan tool, select RSS OUTPUTS, and then RS 006 (ELC COMP). Cycle air compressor. Operate air compressor for 60 seconds. Using a soap and water solution, check air line connection at air drier for leaks. If leaks are found and repaired, go to step 16). If no leaks are found, go to next step.
Turn ignition off. Disconnect air line from air drier. Connect Pressure Gauge (J 22124-B ) to air drier. Close pressure gauge toggle valve. Disconnect RSS control module connector. RSS control module is located in right front corner of trunk. Turn ignition on, with engine off. Connect a jumper between ELC compressor relay control circuit terminal (Yellow wire) of RSS control module harness connector and ground. See WIRING DIAGRAMS. Air compressor should activate. If pressure builds to 80 psi (5.6 kg/cm2 ), go to next step. If pressure does not build to 80 psi (5.6 kg/cm2 ), go to step 10).
When pressure builds to 80 psi (5.6 kg/cm2 ) remove jumper to turn air compressor off. Monitor pressure gauge for one minute. If pressure leaks down, go to step 10). If pressure does not leak down, go to next step.
Connect pressure gauge to right rear shock absorber. Pressure gauge toggle valve should be positioned on side away from shock absorber. Close pressure gauge toggle valve. Apply shop air into pressure gauge schrader valve until pressure gauge indicates 80 psi (5.6 kg/cm2 ). Monitor pressure gauge for one minute. If pressure leaks down, go to step 11). If pressure does not leak down, go to next step.
Slowly open pressure gauge toggle valve to release air pressure. Disconnect pressure gauge from right rear shock absorber. Connect pressure gauge to left rear shock absorber. Pressure gauge toggle valve should be positioned on side away from shock absorber. Close pressure gauge toggle valve. Apply shop air into pressure gauge schrader valve until pressure gauge indicates 80 psi (5.6 kg/cm2 ). Monitor pressure gauge for one minute. If pressure leaks down, go to step 12). If pressure does not leak down, go to next step.
Slowly open pressure gauge toggle valve to release air pressure. Disconnect pressure gauge from left rear shock absorber. Connect pressure gauge to left and right rear air line connections. Reconnect air line to air drier. Open pressure gauge toggle valve. Apply shop air into pressure gauge schrader valve until pressure gauge indicates 80 psi (5.6 kg/cm2 ). Monitor pressure gauge for one minute. If pressure leaks down, go to step 14). If pressure does not leak down, go tostep 19).
Replace ELC air compressor assembly. Replace air lines. After repairs, go to step 19).
Slowly open pressure gauge toggle valve to release air pressure. Replace right rear shock absorber. Reconnect all air lines. After repairs, go to step 19).
Slowly open pressure gauge toggle valve to release air pressure. Replace left rear shock absorber. Reconnect all air lines. After repairs, go to step 19).
If any air lines are damaged, go to next step. If air lines are okay, go to step 18).
Replace air line from air drier to rear shock absorbers. After repairs, go to next step.
Remove air drier from ELC air compressor assembly. With head-connection end down, shake air drier. If water/moisture comes out of air drier when shaken, go to next step. If water/moisture does not come out of air drier when shaken, go to step 17).
Replace air drier. After repairs, go to next step.
Replace air compressor head. After repairs, go to next step.
Install ELC air compressor assembly onto vehicle. Reconnect all air lines. After repairs, go to next step.
Turn ignition off. Reinstall/reconnect all components/connectors. Turn ignition on, with engine off. Clear road-sensing suspension codes. Wait 5 minutes. If rear of vehicle is level, system is okay.

TROUBLE SHOOTING
If ELC system is not properly functioning and no codes are set, check the following.
Check rear position sensors for disconnected or damaged links.
If air compressor operates continuously, check for a short to voltage in ELC air compressor motor circuit (Dark Green wire), or for ELC compressor relay stuck closed.
If air compressor will not turn on, check for ELC compressor relay stuck open.
If air compressor does not operate at full performance, check for a weak battery.
If vehicle rear is high and no road-sensing suspension codes are set, check mechanical portion of exhaust solenoid valve.
If ride is rough, cause may be lack of residual pressure in rear shock absorbers. Perform ELC system leak/performance test. See ELC SYSTEM LEAK/PERFORMANCE TEST.
If circuit breakers are tripped, check for no head relief, a faulty air compressor motor, or short to ground in ELC air compressor motor ground circuit (Black wire). If air compressor motor is faulty, replace ELC air compressor assembly.


Dr Loot
Dec 8, 2010.


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