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Home >> Ford >> 2006 >> Focus ZX5 SE, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 218 (Engine Controls - Pinpoint Tests - 6.0L (99P F450/550) Diesel) >> Pinpoint Test X: Exhaust Pressure (EP) Sensor >> Test Procedure

Test Procedure

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  1. X1 PRELIMINARY DIAGNOSIS FOR DTCS P0470, P0471, P0472, OR P0473 
    NOTE: Diagnose and repair EP sensor circuit fault DTCs before addressing range/performance concerns.
    • Carry out a visual inspection.
    • Retrieve and record all DTCs.
    • Record the freeze frame data.
    • Clear the DTCs.
    • Carry out the KOEO self-test.
    • Carry out the KOER self-test.

    Are DTCs P0470, P0471, P0472, or P0473 present? 

    Yes No
    For KOEO DTC P0470, GO to  X2.
    For continuous memory DTC P0470, GO to  X7.
    For DTC P0471, GO to  X9.
    For DTC P0472, GO to  X13.
    For DTC P0473, GO to  X17.    		 GO to  X20.
  2. X2 DIAGNOSTIC TROUBLE CODE (DTC) P0470 
    • Possible causes:
      • EP sensor
      • SIGRTN circuit open or shorted to ground
      • PCM
    • Key ON, engine OFF.
    • Access the PCM and monitor the EP PID.

    Is the EP PID less than 127 kPa (18.5 psi)? 

    Yes No
    GO to  X3. GO to  X4.
  3. X3 CHECK FOR KOEO DTC P0470 
    • Clear the DTCs.
    • Repeat the KOEO on-demand self-test.

    Is DTC P0470 present? 

    Yes No
    GO to  X13. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary. REFER to SYMPTOM CHARTS , if a driveability concern exists.
  4. X4 CHECK THE EP SENSOR PRESSURE 
    • Access the PCM and monitor the EP, MAP and BARO PIDs.
    • Refer to REFERENCE VALUES for normal operating values.

    Is the EP PID value within 10.34 kPa (1.5 psi) of the MAP and BARO PID values? 

    Yes No
    GO to  X6. GO to  X5.
  5. X5 CHECK THE SIGNAL RETURN CIRCUIT 
    • Key in OFF position.
    • EP Sensor connector disconnected.
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) EP Sensor Connector, Harness Side ( - ) PCM Connector, Harness Side
      SIGRTN - Pin 1 SIGRTN - Pin B20, B33, E25

    Are the resistances less than 5 ohms? 

    Yes No
    INSTALL a new EP sensor. REPAIR the circuit.
    CLEAR the DTCs. REPEAT the self-test. CLEAR the DTCs. REPEAT the self-test.
  6. X6 CHECK THE EP SENSOR 
    CAUTION: Using air pressure greater than 69 kPa (10 psi) may damage the EP sensor.
    • Remove the EP sensor.
    • Check for contamination, restrictions or carbon build-up in the EP sensor port, mounting bracket or tube. Repair as necessary.
    • Check for moisture in the EP sensor port. If moisture is present, use 69 kPa (10 psi) regulated air pressure to remove the moisture.
    • EP Sensor connector connected.
    • PCM connector connected.
    • Key ON, engine OFF.
    • Access the PCM and monitor the EP, MAP and BARO PIDs.

    Is the EP PID value within 10.34 kPa (1.5 psi) of the MAP and BARO PID values? 

    Yes No
    UNABLE to duplicate the condition. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary. REFER to SYMPTOM CHARTS , if a driveability concern exists. INSTALL a new EP sensor.
    CLEAR the DTCs. REPEAT the self-test.
  7. X7 CONTINUOUS DIAGNOSTIC TROUBLE CODE (DTC) P0470 
    • Possible causes:
      • EP sensor
      • PCM
    • Key ON, engine OFF.
    • Access the PCM and monitor the EP PID.
    • Observe the PID while carrying out the following:
      • Grasp the vehicle harness close to the EP sensor connector.
      • Wiggle and shake the vehicle harness while working toward the PCM

    Does the EP PID value fluctuate? 

    Yes No
    ISOLATE the intermittent connection. REPAIR as necessary.
    CLEAR the DTCs. REPEAT the self-test.    		 GO to  X8.
  8. X8 INSPECT THE EP SENSOR AND PCM CONNECTORS 
    • Key in OFF position.
    • EP Sensor connector disconnected.
    • Inspect the EP sensor connector and terminals.
    • Inspect the PCM connectors.

    Are all the connections OK? 

    Yes No
    UNABLE to duplicate the condition. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary. REFER to SYMPTOM CHARTS , if a driveability concern exists. REPAIR as necessary.
    CLEAR the DTCs. REPEAT the self-test.
  9. X9 DIAGNOSTIC TROUBLE CODE (DTC) P0471 
    NOTE: Visually inspect the vehicle for aftermarket accessories and performance modifications (exhaust system, turbocharger, performance chip). Refer to DIESEL ELECTRONIC ENGINE CONTROL (EEC) SYSTEM , Modifications to OBD Vehicles.
    • Possible causes:
      • EP sensor
      • EP sensor supply tube plugged or restricted
      • PCM
    • Carry out the KOEO self-test. If other DTCs are present, repair before continuing. Refer to DIAGNOSTIC TROUBLE CODE (DTC) DESCRIPTIONS .
    • Access the PCM and monitor the EP PID.
    • Road test the vehicle under hard acceleration while monitoring the EP PID.

    Is the EP increase greater than 25 psi? 

    Yes No
    UNABLE to duplicate the condition. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary. REFER to SYMPTOM CHARTS , if a driveability concern exists. GO to  X10.
  10. X10 INSPECT FOR EXHAUST LEAKS 
    • Inspect the turbo pipe and exhaust manifolds for leaks.

    Are any exhaust leaks present? 

    Yes No
    REPAIR the exhaust leak.
    CLEAR the DTCs. REPEAT the self-test.    		 GO to  X11.
  11. X11 CHECK THE EP SENSOR SUPPLY TUBE 
    • Inspect the EP sensor supply tube.

    Is the EP sensor tube restricted or plugged? 

    Yes No
    INSTALL a new EP sensor tube.
    CLEAR the DTCs. REPEAT the self-test.    		 GO to  X12.
  12. X12 EP SENSOR CHECK 
    • EP Sensor connector disconnected.
    • Install the ICP/EBC Adapter Cable D94T-50-A or equivalent between the EP sensor and the vehicle harness.
    • Key ON, engine running.
    • Measure the voltage between the EP signal circuit and ground on the ICP/EBC Adapter Cable D94T- 50-A.
    • Accelerate the engine to wide open throttle (WOT) several times.

    Is the voltage greater than 1.35 volts during acceleration? 

    Yes No
    CLEAR the DTCs. REPEAT the self-test. If DTC P0471 is present again, INSTALL a new EP sensor.
    GO to  X21. CLEAR the DTCs. REPEAT the self-test.
  13. X13 DIAGNOSTIC TROUBLE CODE (DTC) P0472 
    • Possible causes:
      • EP sensor signal circuit open
      • biased sensor
      • EP sensor signal circuit shorted to ground
      • VREF circuit open
      • EP sensor
      • PCM
    • Key in OFF position.
    • EP Sensor connector disconnected.
    • Key ON, engine OFF.
    • Measure the voltage between:
      ( + ) EP Sensor Connector, Harness Side ( - )
      VREF - Pin 2 Ground

    Is the voltage between 4.5 - 5.5 V? 

    Yes No
    GO to  X14. REPAIR the circuit.
    CLEAR the DTCs. REPEAT the self-test.
  14. X14 CHECK THE EP SENSOR SIGNAL 
    • Access the PCM and monitor the EP PID.
    • Connect a 5 amp fused jumper wire between the following:
      Point A EP Sensor Connector, Harness Side Point B EP Sensor Connector, Harness Side
      VREF - Pin 2 EP - Pin 3

    Is the EP PID voltage approximately 4.5 to 5.5 volts? 

    Yes No
    INSTALL a new EP sensor.
    CLEAR the DTCs. REPEAT the self-test.    		 GO to  X15.
  15. X15 CHECK THE SIGNAL CIRCUIT FOR AN OPEN 
    • Key in OFF position.
    • PCM connector disconnected.
    • Measure the resistance between:
      ( + ) EP Sensor Connector, Harness Side ( - ) PCM Connector, Harness Side
      EP - Pin 3 EP - Pin E27

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  X16. REPAIR the circuit.
    CLEAR the DTCs. REPEAT the self-test.
  16. X16 CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
      ( + ) EP Sensor Connector, Harness Side ( - )
      EP - Pin 3 Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  X21. REPAIR the circuit.
    CLEAR the DTCs. REPEAT the self-test.
  17. X17 DIAGNOSTIC TROUBLE CODE (DTC) P0473 
    • Possible causes:
      • EP signal shorted to voltage
      • SIGRTN circuit open
      • EP sensor
      • PCM
    • Key in OFF position.
    • EP Sensor connector disconnected.
    • The EP sensor is disconnected to simulate the opposite DTC.
    • Key ON, engine OFF.
    • Carry out the KOEO on-demand self-test.

    Is DTC P0472 present? 

    Yes No
    INSTALL a new EP sensor.
    CLEAR the DTCs. REPEAT the self-test.    		 GO to  X18.
  18. X18 CHECK THE EP SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • PCM connector disconnected.
    • Key ON, engine OFF.
    • Measure the voltage between:
      ( + ) EP Sensor Connector, Harness Side ( - )
      EP - Pin 3 Ground

    Is any voltage indicated? 

    Yes No
    REPAIR the circuit.
    CLEAR the DTCs. REPEAT the self-test.    		 GO to  X19.
  19. X19 CHECK THE EP SENSOR SIGNAL RETURN CIRCUIT FOR AN OPEN 
    • Key in OFF position.
    • Measure the resistance between:
      ( + ) EP Sensor Connector, Harness Side ( - ) PCM Connector, Harness Side
      SIGRTN - Pin 1 SIGRTN - Pin E25

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  X21. REPAIR the circuit.
    CLEAR the DTCs. REPEAT the self-test.
  20. X20 CHECK THE EP SENSOR FOR BIAS 
    • Key ON, engine OFF.
    • Access the PCM and monitor the EP, MAP and BARO PIDs.
    • Refer to REFERENCE VALUES for normal operating values.

    Is the EP PID value within 10.34 kPa (1.5 psi) of the MAP and BARO PID values? 

    Yes No
    CHECK the EP sensor and tube for blockage or restrictions. REPAIR as necessary. REFER to SYMPTOM CHARTS , if a driveability concern exists. INSTALL a new EP sensor.
    CLEAR the DTCs. REPEAT the self-test.
  21. X21 CHECK FOR CORRECT PCM OPERATION 
    • Disconnect all the PCM connectors.
    • Visually inspect for:
      • pushed out pins
      • corrosion
    • Connect all the PCM connectors and make sure they seat correctly.
    • Carry out the PCM self-test and verify the concern is still present.

    Is the concern still present? 

    Yes No
    INSTALL a new PCM.
    REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .    		 The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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