Section 97.1 SPN 2631/FMI 1

Section 97.1
SPN 2631/FMI 1

This diagnosis is typically Low Air Flow.‪

Section 97.1.1
Low Air Flow

Check as follows:‪

  1. Inspect air filter and air inlet piping to turbocharger for blockage or leaks.
    1. If blockage or leakage is found, repair as necessary.
    2. If no blockage or leakage is found, go to next step.
  2. Check VPOD for the correct part number and proper air line supply installation and configuration (PWM 10 in MCM Group PGR001_Prop Valve must be configured to “Turbo control”). Is the VPOD installed and configured correctly?
    1. Yes, go to next step.
    2. No, correct the VPOD installation and/or configuration.

      Note: Be sure to also inspect turbo inlet seal, intake manifold and EGR hoses and clamps.

  3. Perform CAC inspection and leak test. Refer to OEM literature for procedure.
    1. If inspection and/or leak test fails, repair as necessary.
    2. If CAC inspection passes, go to next step.
  4. Using the AMA service routine, select “Set fault” and perform an air mass adaptation.
  5. Turn the ignition ON, (key ON, engine OFF).
  6. Check EGR valve operation. Using Activate Outputs Service Routine, command PWM1 to 50% while monitoring EGR actual position. Does EGR actual position read between 47-54%?
    1. Yes, go to next step.
    2. No, go to step 8 .
  7. Command PWM1 to 90% while monitoring EGR actual position. Does the EGR actual position read between 87-94%?
    1. Yes, go to step 12 .
    2. No, go to next step.
  8. Turn the ignition OFF.
  9. Disconnect the EGR valve harness connector.
  10. Inspect connector for damaged, corroded or spread pins.
    1. If damage is found, repair as necessary.
    2. If no damaged pins are found, go to next step.
  11. Remove the EGR valve, inspect valve for heavy soot or coolant contamination or leakage.
    1. If contamination is found, repair root cause as necessary, and replace the EGR Valve.
    2. If no contamination is found, replace the EGR Valve.
  12. With Ignition ON, engine OFF, compare the intake manifold pressure to the compressor inlet pressure. Are the pressures within 0.6 psi of each other?
    1. Yes, go to next step.
    2. No, replace suspect sensor.
  13. Check the inlet air Delta P Sensor, with the ignition ON (key ON engine OFF). Does the inlet air Delta P pressure read 0?
    1. Yes, go to next step.
    2. No, remove and inspect the inlet air Delta P sensor including the systek sensor; look for damaged O-rings or plugged orifices. If no damage is found, replace the inlet air Delta P sensor.
  14. Start the engine.
  15. Check the VPOD (wastegate) operation.
    1. Using Activate Outputs Service Routine, command PWM 10 to 30%; no movement of wastegate actuator rod should be seen.
    2. Command the PWM 10 to 70%; wastegate actuator rod should begin to move.
    3. Command the PWM 10 to 90%; wastegate actuator rod should be fully open. Go to next step.
    4. If the actuator fails to move, verify air supply pressure equals truck air pressure. If pressure is OK, replace the VPOD.
  16. Check the brakegate actuator.
    1. Using the Activate Outputs Service Routine, command SW 4 to ON then OFF.
    2. The brakegate actuator should be fully extended when ON and fully retracted when OFF. Go to next step.
    3. If the actuator does not operate, verify air supply. If OK, inspect the brakegate and actuator arm.
  17. Perform a parked regeneration.
  18. After the parked regen completes, monitor the DPF Inlet Pressure with the engine running at 1500 rpm with no load. Is the DPF Inlet Pressure greater than 2 psi?
    1. Yes, remove and inspect DOC and DPF for blockage/obstruction. If blockage/obstruction is found, replace the suspect component as necessary.
    2. No, obtain a DDDL log file showing the active code and contact the Detroit Diesel Customer Support Center (313–592–5800).


EPA07 MBE 4000 DDEC VI Troubleshooting Guide - 6SE568
Generated on 10-13-2008

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