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Home >> Lincoln >> 1997 >> Mark VIII Base >> Repair and Diagnosis >> Suspension >> Electronic Suspension >> Suspension - Electronic Air >> Trouble Shooting >> Quick Checks Without Scan Tool

Quick Checks Without Scan Tool

NOTE: Following measurements and tests are general system checks. These checks are provided for use if recommended tests have not resolved problem or a New Generation Star (NGS) tester or equivalent is not available.

  1. Disconnect Control Module

    Turn air suspension switch to OFF position. Disconnect control module Black and Gray connectors. Turn air suspension on.

  2. Check Inputs

    Using DVOM, check specified control module harness terminals. Ensure all readings are within specification. See INPUT/OUTPUT CIRCUIT CHECKS  table. If any voltage or resistance reading is not as specified, repair as necessary. After repair(s) are completed, go to next step.
    INPUT/OUTPUT CIRCUIT CHECKS

    Circuit Pin Numbers DVOM Reading
    Module C205 Pin No. 32 To Ground (1) Resistance, Less Than 1 Ohm
    Module Power C204 Pin No. 1 (+) To C205 Pin No. 32 Battery Voltage
    Module Power C204 Pin No. 21 (+) To C205 Pin No. 32 Battery Voltage
    Ignition Signal C204 Pin No. 4 (+) To C205 Pin No. 32 Ignition Switch OFF - Zero Voltage
    Ignition Switch ON - Battery Voltage
    Door Switch Signal C204 Pin No. 5 (+) To C205 Pin No. 32 Both Doors Closed - Zero Voltage
    Either Door Open - Battery Voltage
    Self Test Input (STI) Line C204 Pin No. 6 (+) To C205 Pin No. 32 Voltage - Zero
    Resistance, Greater Than 1000 Ohms
    Air Suspension Service Switch C205 Pin No. 11 (+) To C205 Pin No. 32 Switch OFF - Battery Voltage
    Switch ON - Zero Voltage
    Self Test Output (STO) Line C205 Pin No. 12 (+) To C205 Pin No. 32 Ignition OFF - Battery Voltage
    Ignition ON - 6 Volts
    Left Front Spring Solenoid C205 Pin No. 14 To C205 Pin No. 32 Resistance, 14-18 Ohms, Nominal 16 Ohms
    Right Front Spring Solenoid C205 Pin No. 15 To C205 Pin No. 32 Resistance, 14-18 Ohms, Nominal 16 Ohms
    Left Rear Spring Solenoid C205 Pin No. 16 To C205 Pin No. 32 Resistance, 14-18 Ohms, Nominal 16 Ohms
    Right Rear Spring Solenoid C205 Pin No. 17 To C205 Pin No. 32 Resistance, 14-18 Ohms, Nominal 16 Ohms
    Compressor Relay Control Line C205 Pin No. 18 (+) To C205 Pin No. 32 Battery Voltage
    Vent Solenoid C205 Pin No. 30 To C205 Pin No. 32 Resistance, 19-24 Ohms, Nominal 21 Ohms
    (1) Ensure ground connection is clean and tight before measurements are made.

  3. Check Solenoid & Relay Outputs

    Ensure Black and Gray control module connectors are still disconnected. Leave air suspension switch on. Make a jumper wire with an in-line fuse rated at 5 amps or less. Connect jumper wire between C204 pin No. 1 (Dark Green/Yellow wire) and following pins at control module connector C205 (Gray connector):
    • Left front air spring solenoid - pin No. 14 (Light Green/Orange wire)
    • Left rear air spring solenoid - pin No. 16 (Purple/Light Green wire)
    • Right front air spring solenoid - pin No. 15 (Orange/Red wire)
    • Right rear air spring solenoid - pin No. 17 (Light Blue/Black wire)
    • Vent solenoid - pin No. 30 (Pink wire)
    .

    As each solenoid is energized and de-energized, a click should be heard. If all solenoids function as specified, go to next step. If any solenoid does not function as specified, repair solenoid circuit as necessary. After repair is completed, go to next step.

  4. Run Compressor

    Connect jumper wire between ground C205 pin No. 32 (Gray wire) and compressor relay control circuit, C205 pin No. 18 (Dark Blue/Yellow wire). Ensure air suspension system compressor runs when ground is applied to pin No. 18, and stops when ground is removed. If compressor operates as specified, go to next step. If compressor does not operate as specified, repair compressor circuit as necessary.

  5. Check Height Sensors

    Reconnect control module connectors. Ensure air suspension switch is in ON position. Turn ignition on. Using DVOM, backprobe following pins of control module connectors:
    • To check height sensor power, backprobe C205 pin No. 28 (+) (Pink/White wire) to C204 pin No. 10 (-) (Black/Pink wire). Voltage should read 5 volts.
    • To check left front height sensor signal, backprobe C204 pin No. 7 (+) (Pink/Black wire) to C204 pin No. 10 (-) (Black/Pink wire). Record voltage and go to next step.
    • To check right front height sensor signal, backprobe C204 pin No. 8 (+) (Tan wire) to C204 pin No. 10 (-) (Black/Pink wire). Record voltage and go to next step.
    • To check left rear height sensor signal, backprobe C204 pin No. 9 (+) (Orange/Black wire) to C204 pin No. 10 (-) (Black/Pink wire). Record voltage and go to next step.
  6. Maximum voltage should be 4.5 volts, and minimum voltage should be .5 volt. When vehicle is at normal ride height, voltage should be 2.5 volts. When corners of vehicle are bounced, voltage should fluctuate. If any voltage reading is not as specified, repair as necessary.
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