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Home >> Ford >> 1996 >> Aerostar Van Window >> Repair and Diagnosis >> External Pages >> Different car >> Section 199 (Engine Controls - Tests W/Codes - 7.3L Diesel - EEC-IV) >> Pinpoint Tests >> Pinpoint Test AP: Auxiliary Powertrain Control System >> Diagnostic Aids

Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 1996 Ford RV Cutaway, 1996 Ford Pickup, 1996 Ford F-Super Duty, 1996 Ford Econoline, and 1996 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
    NOTE: On 1995 non-speed control equipped vehicles, PCM may be incorrect. On M/T models, processor catch-word must be SOD4 or later. On F250 and F350 A/T models, catch-word must be TEE5 or later. On all models, catch-word tag is located on vehicle "A" pillar or PCM.

  1. 1) Verify Operation Procedure
    Verify vehicle has a 1995 or later calibration. Refer to auxiliary powertrain control manual provided with system to verify correct operation procedures and entry conditions. If entry conditions are met and correct calibration installed, go to next step. If entry conditions are not met or correct calibration is not installed, correct operation procedure or calibration level as necessary. Retest system. If system still does not operate. Go to next step.

  2. 2) Check For DTCs

    If vehicle is equipped with pre-1995 calibration, New Generation Star (NGS) tester cannot be used to perform self-test. Update calibration and retest. If still unable to perform self-test, go to TEST AF, step  1). Ensure auxiliary powertrain control system is off. Using NGS tester, perform KOEO and KOER SELF-TEST . If any DTCs are present, service DTCs as necessary. If no DTCs are present, go to next step.

  3. 3) Check KEY PWR Voltage

    Disconnect APCM connector. Connector is located center of instrument panel. Turn ignition on. Measure voltage between ground and terminal No. 2 at APCM wiring harness connector. If battery voltage is present, go to next step. If battery voltage is not present, locate and repair open in KEY PWR circuit.

  4. 4) Check Ground Circuit

    Turn ignition off. Measure resistance between ground and terminal No. 1 (Black wire) at APCM wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, locate and repair open circuit in Black wire.

  5. 5) Check For Open In BUS (-) Circuit

    Measure resistance of Pink/Light Blue wire between terminal No. 2 at APCM wiring harness connector and Data Link Connector (DLC). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in BUS (-) circuit.

  6. 6) Check For Open In BUS (+) Circuit

    Measure resistance of Tan/Orange wire between terminal No. 4 at APCM wiring harness connector and Data Link Connector (DLC). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, locate and repair open in BUS (+) circuit.

  7. 7) APCM Inoperative With Hazard Flashers

    Turn ignition off. Depress brake pedal. If hi-mount brakelight is illuminated, go to TEST K, step  1). If hi-mount brakelight is off, go to next step.

  8. 8) Check Hi-Mount Brakelight

    Remove and inspect hi-mount brakelight bulb. Replace bulb as necessary and retest system operation. If bulb is okay, go to next step.

  9. 9) Check Ground Circuit

    Measure resistance of Black wire between ground and hi-mount brakelight bulb socket. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, locate and open in ground circuit.

  10. 10) Check For Power To Bulb

    Turn ignition off. Depress brake pedal. Measure voltage between ground and Dark Green wire at hi-mount brakelight bulb socket. If battery voltage is present, check for loose connection in bulb socket. Repair as necessary. If battery voltage is not present, repair open circuit.

  11. 11) Econoline Cutaway Only: APCM Inoperative With Hazard Flashers

    Turn ignition off. Disconnect brake resistor, located on left "B" pillar. Measure resistance of Black wire between resistor harness connector and chassis ground. If resistance is less than 5.0 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black wire.

  12. 12) Check Power To Resistor

    Apply brake pedal. Connect a test light between ground and Light Green wire at resistor harness connector. If test light is illuminated, go to next step. If test light is off, locate and repair open circuit in Light Green wire.

  13. 13) Check Resistor

    Measure resistance between resistor terminals. If resistance is 260-280 ohms, reconnect resistor and go to TEST K, step  1). If resistance is not 260-280 ohms, replace resistor. Recheck system operation.
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