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Home >> Suzuki >> 2007 >> Reno Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> Engine Control Systems >> Engine - Diagnostic Codes (2 Of 4) >> DTC P0404: Exhaust Gas Recirculation (EGR) Open Position Performance >> Test Description

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

  1. The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and to store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
  2. Commanding the EGR valve open determines whether the EGR system can control the EGR valve accurately and if the fault is present. The difference between the current and commanded position is greater than 15%.
  3. When the EGR valve electrical connector is disconnected, the scan tool should display the Actual EGR Position as 0%. If it does not, the fault lies either in the EGR signal circuit or the ECM.
  4. There may be a slight delay for the voltage displayed on the DVM to change after the scan tool commands the EGR valve to operate.
  5. An open or poor connection condition may have caused this DTC to set. Be sure to check the terminals for being backed out, improperly formed or damaged, and for poor tension.
  6. The test light will have glowed brightly in the previous step if the EGR control circuit was shorted to B (+) and the Actual EGR Position on the scan tool will display 100%. A test light that did not illuminate, indicates that the circuit may be open or shorted to ground.
  7. If the EGR valve 5 volt reference is shorted to voltage, the digital voltmeter (DVM) will read battery voltage and additional DTCs may be set and the engine performance will be poor.
  8. The replacement ECM must be reprogrammed.
  9. Although the circuitry acted correctly when checked, a problem may still lie within the terminals which would not show up in probe type testing. Be sure to check the terminals for being backed out, improperly formed or damaged, and for poor tension.
  10. All circuits to the EGR valve are OK at this point. The fault lies internally in the EGR valve and, there fore, must be replaced. Be sure all gasket material is removed from the EGR mounting surface. Even a small amount of material may cause a DTC P0401 to set.
  11. Check the terminals for being backed out, improperly formed or damaged, and for poor tension.
  12. Clearing DTCs is a very important step for this diagnostic. The clearing function allows the EGR valve to relearn a new pintle position as the old pintle position was inaccurate due to the failure that caused the DTC. The DTC must be cleared with the ignition ON, engine OFF or when the engine is idling. If the ECM sees a EGR command, the new pintle will not be learned.
  13. If no malfunctions have been found at this point and no additional DTCs were set, refer to Diagnostic Aids for additional checks and information.
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