Suspension - Automatic Level Control Mazda MPV V

APPLICATION - PARTS IDENTIFICATION

You will need the following Special Service Tools for preparation. (Scheme 2)

Automatic Load Leveling (ALL) - Identification & Location. Scheme 1

Automatic Load Leveling (ALL) - Parts. Scheme 2

DESCRIPTION

The Automatic Load Leveling (ALL) found on towing package equipped models is installed to detect changes in height of the rear of the vehicle caused by load changes and to regulate the rear vehicle height to maintain the proper front-to-rear attitude. (Scheme 1)

VEHICLE HIGHER THAN DESIGNATED HEIGHT (ENGINE RUNNING)

1. Height sensor malfunction.
2. Improperly adjusted height sensor rod.
3. Exhaust valve stuck or damaged disconnected wiring.
4. Exhaust valve passage clogged or damaged/disconnected harness.
5. Control unit malfunction
6. Air pipe clogged.
7. Height sensor electrical circuit damaged/disconnected.

VEHICLE LOWER THAN DESIGNATED HEIGHT (ENGINE RUNNING)

1. Height sensor malfunction.
2. Improperly adjusted height sensor rod.
3. Poor contact of compressor relay of damaged/disconnected wiring.
4. Insufficient output pressure of compressor.
5. Compressor motor malfunction.
6. Control unit malfunction.
7. Air pipe clogged or leaking.
8. Air leakage from shock absorber.
9. Damaged shock absorber rolling diaphragm.
10. Height sensor electricaal circuit damaged/disconnected.

VEHICLE OCCASIONALLYCHANGES (UP OR DOWN) (ENGINE RUNNING)

1. Improperly adjusted height sensor rod.
2. Control unit malfunction.

VEHICLE HIGHER THAN DESIGNATED HEIGHT (IGNITION OFF)

1. Exhaust valve passage clogged or damaged/disconnected harness.
2. Air pipe clogged.
3. Height sensor malfunction.
4. Improperly adjusted height sensor rod.

VEHICLE LOWER THAN DESIGNATED HEIGHT (IGNITION OFF)

1. Damaged exhaust valve.
2. Air leakage at air pipes or shock absorber connection.

HCS INDICATOR REMAINS ILLUMINATED (ENGINE RUNNING)

1. Height sensor malfunction or damaged/disconnected wiring.
2. Improperly adjusted height sensor rod.
3. Alternator harness damaged or disconnected.
4. Alternator malfunction.
5. Exhaust valve stuck or damaged/ disconnected wiring.
6. Exhaust valve leakage.
7. Insufficient compressor output pressure or compressor motor malfunction.
8. Control unit malfunction.
9. Air leakage air pipes or shock absorber connection.
10. Damaged shock absorber rolling diaphragm.

ALL INDICATOR (LEVELLER) WON'T STOP FLASHING (ENGINE RUNNING)

1. Exhaust valve leakage.
2. Insufficient compressor output pressure.
3. Control unit malfunction.
4. Air pipe clogged or air leakage from valve or shock absorber.
5. Damaged shock absorber rolling diaphragm.

COMPRESSOR OPERATES TOO OFTEN (ENGINE RUNNING)

1. Exhaust valve stuck or harness short circuit.
2. Exhaust valve air leakage.
3. Air leakage at air pipes or shock absorber connection.
4. Damaged shock absorber rolling diaphragm.
5. Control unit malfunction.
6. Door switch malfunction.
7. Speed sensor malfunction.

COMPRESSOR DOESN'T STOP (ENGINE RUNNING)

1. Exhaust valve stuck or harness short circuit.
2. Compressor relay malfunction.
3. Control unit malfunction.
4. Air leakage at air pipes or shock absorber connection.
5. Damaged shock absorber rolling diaphragm.

COMPRESSOR WON'T STOP (ENGINE RUNNING)

1. Alternator malfunction.
2. Compressor malfunction.
3. Compressor motor internal wiring damaged/disconnected.
4. Control unit malfunction.
5. Compressor relay malfunction.
6. Door switch malfunction.

COMPRESSOR SPEED TOO SLOW (ENGINE RUNNING)

1. Compressor relay malfunction.
2. Compressor motor malfunction.

ELECTRICAL SYSTEM TROUBLE SHOOTING MAIN FLOW CHART

(Scheme 3)for troubleshooting main flow chart.

Troubleshooting - Main Flow Chart. Scheme 3

SELF-DIAGNOSIS

After the check terminal is grounded and the ignition switch is turned ON, the control unit will change to the self-diagnostic check mode. (Scheme 4) The diagnostic self-check mode checks the operation of the air-intake system, exhaust system, and vehicle-height sensor. If a problem is indicated, the ALL indicator begins flashing, and the system with the malfunction will be indicated by the pattern of the flashing.

Self Diagnostic Check Mode - Identification. Scheme 4

PREPARATIONS

Check that tire pressures are as specified. Adjust as necessary. The work should be done on a surface that is smooth and flat. Check that there is no cargo, luggage, or other load in the vehicle.

Scheme 5

Scheme 6

1. Ground the check connector and turn the ignition switch ON to set the ALL system to the check mode. (Scheme 5) CAUTION: DO NOT start the engine. (Scheme 5): Check Connector - Location (Scheme 6): Standard Height - Location
2. After return to the standard height, look for flashing of the ALL indicator. (Scheme 6)

Vehicle Height

Rear: 392 ± 20 mm (15.4 ± 0.8 in.)

Possible Causes

(Scheme 7)thru (Scheme 11) for possible causes.

Automatic Load Leveling Codes - 1 of 5. Scheme 7

Automatic Load Leveling Codes - 2 of 5. Scheme 8

Automatic Load Leveling Codes - 3 of 5. Scheme 9

Automatic Load Leveling Codes - 4 of 5. Scheme 10

Automatic Load Leveling Codes - 5 of 5. Scheme 11

CHECKING AIR PIPES FOR LEAKAGE

1. Apply soap and water solution to areas indicated by the arrows in (Scheme 12).
2. Apply battery voltage (12V) between terminals (a) and (d) of the compressor connector to activate the compressor and build pressure in the pipes.
3. Check for bubbles.

Note. The air pipes are damaged by battery fluid, which may result in air leakage. Be extremely careful not to permit battery fluid or similar liquids to contact the pipes.

Air Pipes - Checking For Leakage. Scheme 12

CHECKING AIRFLOW THROUGH AIR PIPES

1. Disconnect both ends of the air pipe to be checked.
2. Blow air through the pipe to verify clear passage.

Inspection

(Scheme 13)and (Scheme 14).

1. Remove the No. 1 rear seat.
2. Remove rear side trim A.
3. Connect the connector to the control unit.
4. Check the voltage of the connector terminals as described in the «CONDITIONS & TERMINAL VOLTAGE INFORMATION»(/mazda/mpv/v-1986-1991/remont/electronic-suspension/#suspension-automatic-level-control) table.

CONDITIONS & TERMINAL VOLTAGE INFORMATION

Control Unit - Checking Voltage Connector Terminals. Scheme 13

Control Unit - Wiring Diagram. Scheme 14

Scheme 15

Scheme 16

1. Using screwdriver or similar tool, remove cover from height sensor connector. (Scheme 15)
2. Check for 5V at terminal (a) of the connector. (Scheme 15): Height Sensor - 5V Terminal Location (Scheme 16): Connector Terminal Sensor Links - Location
3. Check that voltages shown in the following table are present at terminals (c), (d), and (b) when the rod is moved.

Scheme 17

1. Measure height sensor rod as shown in figure. (Scheme 17) Sensor rod length should measure 2.16" ± 0.02" (55 ± 0.5 mm). (Scheme 17): Height Sensor - Length Measurement
2. If the rod length is not as specified, adjust as described below. Also (Scheme 18) Loosen the turnbuckle tightening nuts (1). Adjust the length by turning the center bolt (2). Tighten the nuts (1) to 69-95 Inch Lbs (7.8-11 N.m). NOTE: Adjust the rod length as necessary. See below: Lengthen to increase vehicle height. Shorten to decrease vehicle height.

Height Sensor - Tightening Torque. Scheme 18

Checking Rolling Diaphram For Damage

If, no air is in the air cylinders and the vehicle is jacked up and then lowered suddenly, the rolling diaphragm may be folded double (Scheme 19)

If vehicle is driven in this condition, the diaphragm will be damaged. Check for damage visually or by feeling the diaphragm by hand. If it is folded, repair as described below.

1. Ground the check connector and turn the ignition switch ON to set the ALL system to the check mode. (Scheme 20)
2. The diaphragm will be completely stretched and returned to its normal position.
3. Disconnect the check terminal.

Note. Always strictly follow the notes below when lowering the vehicle after it has been jacked up. If the pressure of the shock absorber air cylinders is abnormally low (such as, for example, if the air pipe was removed and then reinstalled before jacking up), disconnect the air pipe before lowering the jack slowly. (Scheme 21) Check that the ALL indicator is not flashing, even if the system is normal, before lowering the jack slowly.

Rear Shock Absorbers Rolling Diaphragm - Identification. Scheme 19

Check Connector - Location. Scheme 20

Air Pipe - Location. Scheme 21

Checking For Air Leakage

If the location of an air leak cannot be found by using a soap and water solution, check as described below.

1. Remove shock absorber. Visually check diaphragm for damage. Using the SST make connections (Scheme 22)
2. Apply approximately 71 psi (5 kg/cm 2 ) air pressure. Place the shock absorber in a tank of water and check for air leakage. (Scheme 23) NOTE: Be careful not to mistake foam (already on the outer surface of the shock absorber) for leakage from inside.
3. Remove all moisture by blowing with compressed air after the check is finished. If the above check shows air leakage from the shock absorber, replace the shock absorber assembly.

SST Connection - Identification. Scheme 22

Shock Absorber - In Tank Of Water. Scheme 23

Checking Compressor And Exhaust Valve

1. Raise rear of vehicle. Support with safety stands. Remove air pipes from shock absorbers. See «CHECKING AIRFLOW THROUGH AIR PIPES»(/mazda/mpv/v-1986-1991/remont/electronic-suspension/#suspension-automatic-level-control__checking-airflow-through-air-pipes). Connect the SST as shown. (Scheme 24)
2. Apply battery voltage (12V) between terminals (a) and (b) of the compressor connector to activate the compressor. (Scheme 25) Close the valve on the pressure gauge, and check the output pressure. Standard pressure is 142-185 psi (10-13 kg/cm 2 ).
3. Turn off compressor. While maintaining the compressor pressure, apply battery voltage (12V) between terminals (c) and (b) of the compressor connector. (Scheme 26)
4. Verify that the exhaust valve operation sound is heard and that the pressure gradually decreases. Check that the correct pressure is reached and held. Preassure should read 2.8-11 psi (0.2-0.8 kg/cm 2 ).
5. Lower vehicle slowly. Connect air pipe(s) to shock absorber(s). (Scheme 27) Tighten to 113-156 Inch Lbs. (13-18 N.m).

SST Connection & Air Pipes - Location. Scheme 24

Battery Voltage & Terminals - Location. Scheme 25

Compressor Pressure & Terminals - Location. Scheme 26

Air Pipe & Shock Absorbers - Location. Scheme 27

Remove compressor relay. Connect battery voltage (12V) to terminal (b) and ground terminal (a). (Scheme 28) Verify continuity between terminal (c) and (d). (Scheme 28)

Compressor Relay, Battery Voltage & Terminals - Location. Scheme 28

AIR PIPES

(Scheme 29)for A, B and C.

Removal & Installation - (A) Type

Press at the base of the plug, and then pull the air pipe to disconnect it. To reconnect, push in until the air pipe's ridge catches on the tab on the plug.

Removal & Installation - (B) Type

Remove the boot from the joint. Firmly grasp the air pipe joint tabs and pull out. To reconnect, push in until a click is heard; then pull slightly to be sure the connection is secure. Cover the joint with the boot.

Removal & Installation - (C) Type

Remove the pipe by removing the nut. Install the pipe by tightening the nut.

Air Pipes - Checking Air Flow. Scheme 29

Removal & Installation

1. Jack up the rear of the vehicle and support it with safety stands.
2. Turn the spare tire carrier bolt counterclockwise and let the spare tire carrier down about 300 mm (11.8 in.).
3. Disconnect harness connector. Remove height sensor retaining bolts and nuts and height sensor. Install in reverse order of removal. (Scheme 30) Tighten bracket-to-body retaining bolt to 13-20 Ft. Lb. (18-26 N.m).

Height Sensor Removal & Installation. Scheme 30

Adjustment

1. Measure height sensor rod as shown in figure. (Scheme 17) Sensor rod length should measure 2.16" ± 0.02" (55 ± 0.5 mm).
2. If the rod length is not as specified, adjust as described below. Also (Scheme 18) Loosen the turnbuckle tightening nuts (1). Adjust the length by turning the center bolt (2). Tighten the nuts (1) to 69-95 Inch Lbs (7.8-11 N.m). NOTE: Adjust the rod length as necessary. See below: Lengthen to increase vehicle height. Shorten to decrease vehicle height.

Remove in order (Scheme 31) Install in the reverse order of removal. Tighten all nuts and bolts to specification.

Compressor Assembly - Identification. Scheme 31

See also:
• CONDITIONS & TERMINAL VOLTAGE INFORMATION
• CHECKING AIRFLOW THROUGH AIR PIPES