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Home >> Ford >> 2003 >> Excursion 6.0 P, 4WD >> 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 De: Exhaust BACKPRESSURE Sensor >> Testing

Test De: Exhaust BACKPRESSURE Sensor: 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
P0470 Test DE  , Step  1)   Test DE  , Step  3)
P0471 (1)     Test DE  , Step  5)
P0472 Test DE  , Step  9)   Test DE  , Step  9)
P0473 (1) Test DE  , Step  15)   Test DE  , Step  15)
P0478     Test DE  , Step  17)
(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 P0470: Monitor EBP PID
    DTC P0470 is set when PCM detects an EBP sensor malfunction during KOEO ON-DEMAND SELF-TEST. The following are possible causes for this fault:
    • Faulty EBP Sensor
    • Open EBP Signal Circuit
    • Faulty PCM

    Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, access EBP PID from PID/DATA MONITOR & RECORD menu. If EBP reading is 18.5 psi (127 kPa) or more, go to next step. If EBP reading is less than 18.5 psi (127 kPa), clear DTCs and repeat KOEO ON-DEMAND SELF-TEST  under QUICK TEST. If DTC is still present, replace PCM. Clear DTCs and retest.

  2. 2) Signal Ground Circuit Check

    Turn ignition off. Disconnect EBP sensor connector. Sensor is located on top front of engine. See Figure or Figure . Inspect connector for damaged pins, corrosion and loose wires. Repair connector as necessary. Using DVOM, measure resistance between chassis ground and EBP sensor harness connector terminal "A" (Gray/Red wire). See Figure. If resistance is less than 5 ohms, replace EBP sensor. Clear DTCs and retest. If resistance is 5 ohms or more, repair open in SIG RTN circuit (Gray/Red wire) between PCM and EBP sensor. Clear DTCs and retest.
    3. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  3. 3) Continuous Memory DTC P0470: Monitor EBP PID
    DTC P0470 is set when PCM detects an EBP sensor malfunction during normal driving conditions. The following are possible causes for this fault:
    • Faulty EBP Sensor
    • Faulty Connection
    • Faulty Powertrain Control Module (PCM)

    Ensure scan tool is connected to Data Link Connector (DLC). Using scan tool, access EBP PID from PID/DATA MONITOR & RECORD menu. While observing EBP PID, wiggle and bend small sections of wiring harness starting at EBP sensor connector and working toward PCM. If EBP reading fluctuates, isolate fault and repair as necessary. Clear DTCs and retest. If reading does not fluctuate, go to next step.

  4. 4) Check Connector

    Disconnect EBP sensor connector. Sensor is located on top front of engine. See Figure or Figure . Disconnect 42-pin in-line connector on left side of engine compartment and PCM connector. Inspect connectors for damaged pins, corrosion and loose wires. PCM is located in left rear of engine compartment, near brake master cylinder. Repair connectors as necessary. Clear DTCs and retest. If all connectors are okay, no concern is indicted at this time. Clear DTCs and retest.
    5. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  5. 5) Continuous Memory DTC P0471: Monitor EBP PID
    DTC P0471 is set when PCM detects an EBP sensor malfunction during normal driving conditions and with EBP sensor enabled. The following are possible causes for this fault:
    • Faulty EBP Sensor.
    • Plugged Or Restricted Sensor Supply Tube
    • Damaged Exhaust Pressure Regulator (EPR) Linkage Or Butterfly
    • Faulty PCM

    Perform KOER ON-DEMAND SELF-TEST  under QUICK TEST. If any KOEO DTCs are present, repair fault(s) before continuing with this test. Using scan tool, access EBP PID from PID/DATA MONITOR & RECORD menu. Road test vehicle performing hard accelerations while monitoring EBP PID. If EBP PID reading increases to more than 25 psi with EBP device on, no concern is indicated at this time. Clear DTCs and retest. If EBP reading does not increase to more than 25 psi, go to next step.

  6. 6) Check For Exhaust Leaks

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

  7. 7) Check Sensor Supply Tube

    Inspect EBP sensor supply tube from exhaust manifold to sensor bracket. Sensor is located on top front of engine. See Figure or Figure . Ensure tube is not restricted or plugged. Replace tube as necessary. Clear DTCs and retest. If tube is okay, go to next step.

  8. 8) EBP Sensor Check

    Disconnect EBP sensor connector. Install ICP/EBP Adapter Cable (D94T-50-A) between EBP sensor and sensor harness connector. Start engine and allow it to idle. Using DVOM, measure voltage between signal circuit and signal ground at ICP/EBP adapter cable. Briefly accelerate engine to Wide Open Throttle (WOT) several times. If voltage reading during acceleration is 1.35 volt or more, clear DTCs and retest. If DTC is still present, replace PCM. If voltage reading during acceleration is 1.35 volt or less, replace EBP sensor. Clear DTCs and retest.
    9. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  9. 9) KOEO & Continuous Memory DTC P0472: Check For Open In VREF Circuit
    DTC P0472 is set when PCM detects EBP sensor circuit input low during KOEO ON-DEMAND SELF-TEST or during continuous diagnostic monitoring. The following are possible causes for this fault:
    • Open EBP Signal, SIG RTN Or VREF Circuit
    • Biased Sensor
    • EBP Circuit Shorted To SIG RTN Or PWR GND
    • Faulty PCM

    Turn ignition off. Disconnect EBP sensor connector. Sensor is located on top front of engine. See Figure or Figure . Turn ignition on. Using DVOM, measure voltage between chassis ground and EBP sensor harness connector VREF terminal "B" (Brown/White wire). See Figure. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, repair open in Brown/White wire between PCM and EBP sensor. Clear DTCs and retest.

  10. 10) SIG RTN Circuit Check

    Using DVOM, measure resistance between chassis ground and EBP sensor harness connector SIG RTN circuit terminal "A" (Gray/Red wire). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Gray/Red wire between PCM and EBP sensor. Clear DTCs and retest.

  11. 11) EBP Signal Circuit Check

    Turn ignition off. 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. Install Rotunda Breakout Box (014-00950), leaving PCM disconnected. Using DVOM, measure resistance of Purple/Light Blue wire between EBP sensor harness connector terminal "C" and test pin No. 30 at breakout box. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Purple/Light Blue wire between PCM and EBP sensor. Clear DTCs and retest.

  12. 12) VREF Circuit Check

    Using DVOM, measure resistance of Brown/White wire between at EBP sensor harness connector terminal "B" and test pin No. 90 at breakout box. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/White wire between PCM and EBP sensor. Clear DTCs and retest.

  13. 13) Check For Grounded EBP Signal Circuit

    Using DVOM, measure resistance between test pin No. 30 and test pins No. 25, 51, 76 (Econoline), 77, 91 and 103 at breakout box. If all resistances are more than 10 k/ohms, go to next step. If any resistance is less than 10 k/ohms, locate and repair short to ground in Purple/Light Blue wire between PCM and EBP sensor. Clear DTCs and retest.

  14. 14) Check For Internal PCM Short

    Connect PCM connector to breakout box. Using DVOM, measure resistance between test pin No. 30 and test pins No. 25, 51, 76 (Econoline), 77, 91 and 103 at breakout box. If all resistances are more than 10 k/ohms, replace EBP sensor. Clear DTCs and retest. If any resistance is 10 k/ohms or less, replace PCM. Clear DTCs and retest.
    15. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  15. 15) KOEO & Continuous Memory DTC P0473: Induce Opposite Failure
    DTC P0473 is set when PCM detects EBP sensor circuit input high during KOEO ON-DEMAND SELF-TEST or during continuous diagnostic monitoring. The following are possible causes for this fault:
    • Biased Sensor/PCM
    • EBP Circuit Shorted To VREF

    Disconnect EBP sensor connector. Turn ignition on. Sensor is located on top front of engine. See Figure or Figure . Perform KOEO ON-DEMAND SELF-TEST  under QUICK TEST. If KOEO DTC P0472 is now present, replace EBP sensor. Clear DTCs and retest. If KOEO DTC P0472 is not present, go to next step.

  16. 16) Check EBP Circuit For Short To PWR

    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. Install Rotunda Breakout Box (014-00950), leaving PCM disconnected. Using DVOM, measure resistance between test pin No. 30 and test pins No. 55, 71, 90 and 97 at breakout box. If all resistances are more than 10 k/ohms, replace PCM. Clear DTCs and retest. If any resistance is 10 k/ohms or less, locate and repair short to PWR in EBP signal circuit (Violet/Light Blue wire) between PCM and EBP sensor. Clear DTCs and retest.
    17. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: This procedure is best accomplished either driving vehicle uphill or fully loaded.

  17. 17) Continuous Memory DTC P0478: Check MGP & RPM PIDs
    DTC P0478 is set when PCM detects excessive backpressure existing during normal driving. The following are possible causes for this fault:
    • Stuck EBP Butterfly Valve
    • Restricted Exhaust
    • Plugged EBP Sensor Tube
    • Misadjusted EPR Linkage
    • Wastegate Turbo Possible Overboost (F250-550 Only)

    Connect scan tool to Data Link Connector. Turn ignition on. Using scan tool, access MGP and RPM PIDs from PID/DATA MONITOR & RECORD menu. Road test vehicle in best gear to accelerate at 2500-3000 RPM. Note highest boost pressure. If MGP PID reading is not more than 18 psi (124 kPa) for more than 5 seconds, go to next step. If MGP PID reading is 18 psi (124 kPa) or more for more than 5 seconds, go to TEST KH, step  5).

  18. 18) Inspect Butterfly Tang

    Visually inspect EBP butterfly valve (note tang position). See Fig 1. If valve is in open position, go to next step. If valve is not in open position, repair damaged linkage or butterfly as necessary. Clear DTCs and retest.
    Fig 1: Identifying EBP Butterfly Valve In Open Position
    G95I35277Courtesy of FORD MOTOR CO.

  19. 19) Check For Exhaust Restriction

    Using scan tool, access EBP PID from PID/DATA MONITOR & RECORD menu. Start engine. Briefly accelerate engine speed to Wide Open Throttle (WOT) while monitoring EBP PID. If EBP PID reading is less than 28 psi (193 kPa), go to next step. If EBP PID reading is 28 psi (193 kPa) or more, repair restricted exhaust system. Clear DTCs and retest.

  20. 20) Check EBP System

    Ensure engine is cold and Engine Oil Temperature (EOT) is less than 70°F (21°C). Road test vehicle while monitoring EBP PID reading on scan tool. With EBP sensor on, if EBP reading stays at less than 50 psi, replace PCM. Clear DTCs and retest. With EBP sensor on, if EBP reading does not stay at less than 50 psi, check and adjust turbocharger control rod as necessary. Spring scale reading should be 10 lbs. (4.5 kg). See Fig 2. Clear DTCs and retest.
    Fig 2: Adjusting Control Rod Tension
    G97G03799Courtesy of FORD MOTOR CO.
    21. NOTE: Perform test step 21)  when directed here from RUNS ROUGH, MISSES, BUCKS OR JERKS, HESITATION, STUMBLES, SURGES (ON ACCELERATION OR CRUISE), LACK OR LOSS OF POWER, OR POOR FUEL ECONOMY symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - 7.3L DIESEL article.
    NOTE: F650-750 models are not equipped with EBP.

  21. 21) Check For Biased EBP Sensor
    Turn ignition on. Using scan tool, monitor EBP, MAP and BARO PIDs. If EBP PID value does not deviate from atmospheric pressure (dependent on altitude) by more than 1.5 psi (10 kPa), return to RUNS ROUGH, MISSES, BUCKS OR JERKS, HESITATION, STUMBLES, SURGES (ON ACCELERATION OR CRUISE), LACK OR LOSS OF POWER, OR POOR FUEL ECONOMY , step 21)  under SYMPTOMS in TROUBLE SHOOTING - NO CODES - 7.3L DIESEL article. If EBP PID value deviates from atmospheric pressure (dependent on altitude) by more than 1.5 psi (10 kPa), check wiring and Powertrain Control Module (PCM). If wiring and PCM are okay, replace EBP sensor.
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