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Test DT: Power Steering Pressure Sensor: Testing

    NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  1. 1) For KOER Only DTC P1550: Verify Operator Interaction
    DTC P1550 indicates PSP sensor signal was less than minimum or was more than maximum calibrated limit during KOER self-test. Possible causes for this fault are:
    • Faulty PSP Sensor
    • Faulty Powertrain Control Module (PCM)

    Ensure steering wheel was turned at least 1/2 turn within 30 seconds of starting KOER on-demand self-test. If steering wheel was turned during self-test, repair any symptoms with power steering system that are present. If no power steering symptoms are present, go to next step. If steering wheel was not turned during self-test, repeat QUICK TEST .

    2. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  2. 2) For KOEO & KOER Only DTCs P0552 & P0553, Or For KOEO Only DTC P1550: Check Voltage Between VREF & SIG RTN At PSP Sensor
    DTC P0552 indicates PSP sensor circuit is open or shorted to ground. DTC P0553 indicates PSP sensor circuit is shorted to VPWR. DTC P1550 indicates PSP sensor signal was less than minimum or was more than maximum calibrated limit during KOEO self-test. Possible causes for these faults are:
    • Faulty PSP Sensor
    • SIG RTN Circuit Open Or Shorted
    • VREF Circuit Open Or Shorted
    • PSP Sensor Signal Circuit Open Or Shorted
    • Faulty Powertrain Control Module (PCM)

    Turn ignition switch to OFF position. Disconnect PSP sensor connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using a DVOM, measure voltage between VREF and SIG RTN circuits at PSP sensor harness connector. See Figure. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to TEST C, step  1).

  3. 3) Check PSP Sensor Operation

    Turn ignition switch to OFF position. Connect jumper wire to complete VREF circuit between PSP sensor connector and PSP sensor harness connector. See Figure and Fig 1 . Connect another jumper wire to complete SIG RTN circuit between PSP sensor connector and PSP sensor harness connector. Start engine and allow to idle. Using a DVOM, measure voltage between chassis ground and PSP circuit at PSP sensor connector. See Fig 1. Observe voltage while turning steering wheel at least 1/2 turn to the right and to the left. If voltage is .3-4.7 volts and changes when steering wheel is turned, go to next step. If voltage is not .3-4.7 volts or does not change when steering wheel is turned, replace PSP sensor.
    Fig 1: Testing PSP Sensor Operation
    G00035648Courtesy of FORD MOTOR CO.

  4. 4) Check PSP Sensor Circuit For Open In Harness

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Ensure PSP sensor is disconnected. Using a DVOM, measure resistance of PSP circuit between PSP sensor harness connector and PCM harness connector. See Figure. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in PSP circuit.

  5. 5) Check PSP Circuit For Short To Power In Harness

    Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and PSP circuit at PSP sensor harness connector. See Figure. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR in PSP circuit.

  6. 6) Check PSP Circuit For Short To VREF, SIG RTN & Ground In Harness

    Using a DVOM, measure resistance between PSP circuit, and VREF and SIG RTN circuits at PSP sensor harness connector, and chassis ground. See Figure. If all resistance measurements are more than 10 k/ohms, replace PCM. If any resistance measurement is 10 k/ohms or less, repair short in affected circuit.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 6) to step 10). No test procedures have been omitted.
    7. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  7. 10) For Continuous Memory Only DTCs P0552 & P0553: Check For Intermittent Circuits To PSP Sensor
    DTC P0552 indicates PSP sensor circuit is open or shorted to ground. DTC P0553 indicates PSP sensor circuit is shorted to VPWR. Possible causes for these faults are:
    • Faulty PSP Sensor
    • SIG RTN Circuit Open Or Shorted
    • VREF Circuit Open Or Shorted
    • PSP Sensor Signal Circuit Open Or Shorted
    • Faulty Powertrain Control Module (PCM)

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, access PSP V PID from PID/DATA MONITOR & RECORD. Observe PSP V PID voltage for indication of fault while shaking, wiggling and bending PSP, SIG RTN and VREF circuits between PSP sensor and PCM. Tap lightly on PSP sensor to simulate road shock. An indication of fault is a sudden change in PSP V PID voltage. If a fault is indicated, isolate and repair as necessary. If no fault is indicated, fault is unable to be duplicated at this time. Go to TEST Z, step 1) .

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