Where is the a.i.r. pump located - 1998 Cadillac Catera

The air pump for the secondary air system (emission control device) is located under the battery. If you do replace it, replace the check valve too, it is on top of the exhaust manifold and connected to the pump with a hose. The check valve fails and ruins the pump. Source(s): http://repairpal.com/volvo-850-1997/comm…
http://repairpal.com/air-pump-check-valv…
http://repairpal.com/air-pump

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I think they are talking about the pump to provide vacuum to the climate control when the turbo is putting boost in the intake manifold. The vacuum can come from an electric pump or from an engine driven pump, something like an old engine driven fuel pump. I needed an electric pump for my 765T, and all the wrecking yards wanted to sell me the engine driven form. (A new one was $500, and it wasn't that important to me.)

An engine that takes the engine driven pump will have a hole in it while the others will not have a hole. Source(s): 35 years maintaining my own cars, including 17 years with a 1985 765T


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Rear Suspension Leveling Air Compressor
RH front of vehicle, attached beneath the fascia

Rear Suspension Leveling Air Compressor Relay K19
Lower I/P, to the RH side of the steering column, on the relay box


Automatic Level Control System Operation Check
Support the rear wheels or support the rear lower control arms when certain tests require raising the vehicle on a hoist. Use two additional jack stands in order to support the rear lower control arms in the normal curb weight position when a frame type hoist is used. Refer to Trim Height Specifications in Suspension General Diagnosis.

Refer to ALC Suspension System Check for electrical troubleshooting of the Automatic Level Control (ALC) system, or if DTC's are present.

Diagnosing Leveling Complaints Without DTCs Present Procedure
Perform the following preliminary inspections before performing the system performance test:

Inspect the ignition (pin A & pin H) at the ALC sensor connector.
Ensure that the ignition (pin A & pin H) at the ALC sensor connector connection is secure.
Inspect the ground (pin E) at the ALC sensor connector.
Ensure that the ground (pin E) at the ALC sensor connector connection is secure.
Inspect the ALC sensor link.
Ensure that the ALC sensor link is properly secured to the actuator arm.
Inspect the ALC sensor actuator arm for damage.
ALC Diagnosis Table Step
Action
Value(s)
Yes
No

1
Has the ALC compressor assembly and the air tube been replaced?
--
Go to Step 7
Go to Step 2

2
Raise and support the vehicle. Lifting and Jacking the Vehicle in General Information.
Inspect the air tubes running from the ALC compressor to both rear shock absorbers.
Inspect the air tube connection at the ALC air dryer.
Are the air tubes damaged and/or disconnected?
--
Go to Step 13
Go to Step 3

3
Squeeze the left rear shock absorber in the middle of the air sleeve.

Did the air sleeve slightly compress?
--
Go to Step 5
Go to Step 4

4
Operate the ALC system for 60 seconds.
Test the air tube-to-air dryer connection for leaks using a soap bubble solution.
Is a leak evident?
--
Go to Step 20
Go to Step 5

5
Disconnect the air tube from the ALC dryer.
Connect the Pressure Gauge to the ALC dryer.
Close the toggle valve on the Pressure Gauge .
Operate the ALC compressor.
Did the pressure build to the specified value?
80 psi
Go to Step 6
Go to Step 10

6
Shut off the compressor when the pressure reaches 80 psi.
Monitor the gauge for 1 minute.
Did the pressure leak down?
--
Go to Step 10
Go to Step 7

7
Connect the Pressure Gauge to the right rear shock absorber. Ensure that the toggle valve on the Pressure Gauge is away from the shock absorber.
Close the toggle valve.
Pressurize the shock absorber at the toggle valve on the Pressure Gauge to 80 psi.
Monitor the gauge for 1 minute.
Did the system leak down?
--
Go to Step 11
Go to Step 8

8
Use the toggle valve on the Pressure Gauge in order to slowly release the air pressure.
Disconnect the Pressure Gauge from the right rear shock absorber.
Connect the Pressure Gauge to the left rear shock absorber.
Pressurize the Pressure Gauge to 80 psi.
Monitor the gauge for 1 minute.
Did the pressure leak down?
--
Go to Step 12
Go to Step 9

9
Use the toggle valve on the Pressure Gauge in order to slowly release the air pressure.
Disconnect the Pressure Gauge from the left rear shock absorber.
Connect the Pressure Gauge , inline, at the tee near the rear of the vehicle.
Reconnect the air tube to the ALC dryer.
Open the toggle valve on thePressure Gauge .
Using shop air, pressurize the system to 80 psi at the service connection of the Pressure Gauge .
Monitor the pressure gauge for 1 minute.
Did the pressure leak down?
--
Go to Step 14
Go to Step 20

10
Replace the following components:

• Replace the ALC compressor. Refer to Air Compressor Replacement .

• Replace the air tube. Refer to Air Tube Replacement .

Are the replacements complete?
--
Go to Step 20
--

11
Slowly open the toggle valve on the Pressure Gauge in order to relieve the air pressure.
Replace the right rear shock absorber. Refer to Shock Absorber Replacement in Rear Suspension.
Reconnect all of the air tube connections.
Is the shock absorber replaced, and are all of the air tube connections reconnected?
--
Go to Step 20
--

12
Slowly open the toggle valve on the Pressure Gauge in order to relieve the air pressure.
Replace the left rear shock absorber. Refer to Shock Absorber Replacement in Rear Suspension.
Reconnect all of the air tube connections.
Is the shock absorber replaced, and are all of the air tube connections reconnected?
--
Go to Step 20
--

13
Are any of the air tubes damaged?
--
Go to Step 14
Go to Step 18

14
Replace the air tube that runs from the air dryer to the two rear shock absorbers.

Is the replacement complete?
--
Go to Step 15
--

15
Remove the ALC air dryer from the compressor assembly.
Shake the ALC air dryer with the head connection down.
Did water/moisture come out of the ALC air dryer when the dryer was shaken?
--
Go to Step 16
Go to Step 17

16
Replace the ALC air dryer. Refer to Automatic Level Control Air Dryer Replacement .

Is the replacement complete?
--
Go to Step 17
--

17
Replace the air compressor head. Refer to Automatic Level Control Air Compressor Head Replacement .

Is the replacement complete?
--
Go to Step 18
--

18
Install the ALC compressor on the vehicle.
Reconnect all of the air tube connections.
Is the ALC compressor reinstalled, and are all of the air tube connections reconnected?
--
Go to Step 20
--

19
Repair the air tube-to-air dryer connection leak.

Is the repair complete?
--
Go to Step 20
--

20
Reconnect all of the connectors that were disconnected.
Reconnect all of the components that were removed.
Clear all of the codes with the ignition ON and with the engine OFF.
Wait at least 5 minutes.
Is the rear of the vehicle trim level?
--
System OK
--