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Home >> Ford >> 2003 >> Excursion 6.0 P, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 3 (ENGINE CONTROLS - SELF-DIAGNOSTICS - 7.3L (995, 996 F650/750, 99F E Series & 99F F450/550) DIESEL) >> System Tests >> Test Kb: Exhaust BACKPRESSURE Regulator >> Testing

Test Kb: Exhaust BACKPRESSURE Regulator: Testing

WARNING: This page is about a different variant/trim than selected.
FAULT CODE SETTING CONDITION

Fault Code
(All except F650-750)		 KOEO KOER Continuous Memory
P0475 (1) Test KB  , Step  1)    
P0476   Test KB  , Step  7) Test KB  , Step  7)
(1) MIL illuminates when fault is detected in second drive cycle (California, OBD-II calibration).
    NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  1. 1) KOEO DTC P0475: Check EBR PWR GND Circuit For Open
    DTC P0475 indicates exhaust pressure control valve malfunction. Possible causes are:
    • Faulty EPR Solenoid
    • EPR PWR GND Circuit Open
    • EPR Circuit Open, Or Shorted To Ground Or Power
    • Faulty PCM

    Disconnect EPR connector. EPR is located in turbocharger mounting pedestal on top left rear of engine. See Figure or Figure . Turn ignition off. Using DVOM, measure resistance between chassis ground and Black/White wire at EPR 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 Black/White wire between chassis ground and EPR. Clear DTCs and retest.

  2. 2) Check EPR Coil

    Using DVOM, measure resistance between EPR terminals. If resistance is 2.5-12.0 ohms, go to next step. If resistance is not 2.5-12.0 ohms, replace EPR. Clear DTCs and retest.

  3. 3) Check EPR Circuit For Short To Power

    Disconnect PCM connector and inspect for damaged pins, corrosion and loose wires. PCM is located in left rear of engine compartment, near brake master cylinder. Repair connector as necessary. While shaking wiring harness, measure voltage between chassis ground and Gray/Red wire at EPR harness connector. If battery voltage is not present, go to next step. If battery voltage is present, repair short to voltage in Gray/Red wire between PCM and EPR. Clear DTCs and retest.

  4. 4) Check EPR Circuit For Short To Ground

    While shaking wiring harness, measure resistance between chassis ground and Gray/Red wire at EPR harness connector. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, locate and repair short to ground in Gray/Red wire. Clear DTCs and retest.

  5. 5) Check EPR Circuit For Open

    Install Rotunda Breakout Box (014-00950), leaving PCM disconnected. While shaking wiring harness, measure resistance between Gray/Red wire at EPR harness connector and test pin No. 42 at breakout box. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, locate and repair open circuit in Gray/Red wire. Clear DTCs and retest.

  6. 6) Perform Output State Check

    Reconnect PCM connector. Attach scan tool to Data Link Connector (DLC). Turn ignition on. Using DVOM, measure between chassis ground and Gray/Red wire at EPR harness connector. Perform KOEO OUTPUT STATE SELF-TEST  under QUICK TEST. If voltage does not toggle between 12 volts and zero volt, replace PCM. Clear DTCs and retest. If voltage toggles between 12 volts and zero volt, reconnect all components. No fault is indicated at this time. Clear DTCs and retest.
    7. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: If KOEO EBP DTCs are present, repair them before continuing.

  7. 7) KOER & Continuous Memory DTC P0476: Check EPR Mechanical Operation
    DTC P0476 indicates PCM detected poor exhaust pressure control valve performance malfunction during KOER ON-DEMAND SELF-TEST. Possible causes are:
    • Stuck Or Damaged Turbocharger Wastegate Valve (Butterfly)
    • Misadjusted Or Damaged Linkage
    • Restricted Exhaust
    • Exhaust Leaks
    • Faulty EPR Valve
    • Faulty Exhaust Backpressure (EBP) Sensor
    • Faulty PCM

    Visually inspect turbocharger wastegate valve tang. See Figure. If tang is in Open position, go to next step. If tang is not in Open position, repair damaged linkage or butterfly as necessary. Clear DTCs and retest.

  8. 8) Check For Exhaust Restriction

    Unplug EOT sensor to cause EBR valve to stay open. Using scan tool, access EBP PID from PID/DATA MONITOR & RECORD menu. Start engine and allow it to idle. Briefly accelerate engine speed to Wide Open Throttle (WOT) while monitoring EBP PID. If EBP PID is more than 25 psi (172 kPa), go to next step. If EBP PID reading is 25 psi (172 kPa) or less, go to step  10).

  9. 9) EBP Operation Test

    Inspect exhaust system for damage. Observe EBR valve operation while repeating KOER ON-DEMAND SELF-TEST  under QUICK TEST. If EBR valve cycles and then opens completely (tang against stop), check EBR adjustment. If EBR valve does not cycle and then open completely, go to next step.

  10. 10) Check Electrical System

    Ensure EBP and associated wiring harness and connectors are okay. Repair as necessary. If wiring and connectors are okay, go to next step.

  11. 11) EBP Sensor Check

    Turn ignition on. Using scan tool, access EBP PID from PID/DATA MONITOR & RECORD menu. Start engine and record EBP PID value. While observing scan tool, briefly accelerate engine speed several times. If EBP PID reading increases 4 psi or more with each acceleration, go to next step. If EBP PID reading increases less than 4 psi with each acceleration, replace EBP sensor. Clear DTCs and retest. Sensor is located on top front of engine. See Figure or Figure .

  12. 12) Check For Exhaust Leaks

    Inspect turbo pipe, crossover pipe and exhaust manifolds for leaks. Repair as necessary. Clear DTCs and retest. If no exhaust leaks are found, go to next step.

  13. 13) Check EBP During KOER Self-Test

    Turn ignition off. Disconnect EBP sensor connector. Sensor is located on top front of engine. See Figure or Figure . Install ICP/EBP Adapter Cable (D94T-50-A) between EBP sensor and sensor harness connector. Start engine. Using DVOM, measure voltage between signal circuit and signal ground at ICP/EBP adapter cable. Perform KOER ON-DEMAND SELF-TEST  under QUICK TEST. If voltage increases 1.5-2.5 volts and then decreases as test ends, replace PCM. Clear DTCs and retest. If voltage does not increase 1.5-2.5 volts and then decreases as test ends, go to next step.

  14. 14) EPR Visual Inspection

    Observe EPR valve linkage while performing KOER ON-DEMAND SELF-TEST  under QUICK TEST. If linkage moves during test, check EPR linkage adjustment. See WASTEGATE CONTROL SOLENOID under MOTORS, RELAYS & SOLENOIDS in REMOVAL & INSTALLATION - 7.3L DIESEL article. Adjust as necessary and retest. If linkage does not move during test, replace EPR valve. Clear DTCs and retest.
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