DTC P0404-A: EGR Position Sensor Rationality Failure

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.

Using scan tool, read Diagnostic Trouble Codes (DTCs). If another EGR DTC is present, perform other DTC procedure before performing this procedure. If another EGR DTC is not present, go to next step.
Start engine. Using scan tool, read EGR position sensor voltage. If voltage is more than 4.27 volts, go to next step. If voltage is 4.27 volts or less, replace EGR valve assembly. Perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES .
While driving vehicle at 20 MPH, using a DVOM, measure voltage drop by backprobing on EGR solenoid sensor ground circuit at PCM connector terminal No. 43. If voltage drop is .3 volts or less, go to next step. If voltage drop is more than .3 volts, repair high resistance on sensor ground circuit. Perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES .
Turn engine off. Disconnect EGR solenoid connector. Using a DVOM, check resistance of EGR solenoid connector sensor ground circuit. See EGR SOLENOID CONNECTOR WIRE IDENTIFICATION table. If resistance is more than 5 ohms, go to next step. If resistance is 5 ohms or less, replace PCM. Perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES .
Disconnect PCM connector. Using a DVOM, check resistance of EGR solenoid sensor ground circuit between EGR solenoid connector and PCM connector terminal No. 43. See EGR SOLENOID CONNECTOR WIRE IDENTIFICATION table and PCM CONNECTOR WIRE IDENTIFICATION table. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES . If resistance is 5 ohms or more, repair sensor ground circuit. Perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES .

EGR SOLENOID CONNECTOR WIRE IDENTIFICATION

Application		Wire Color
EGR Solenoid Sensor Ground Circuit		Black/Light Blue

PCM CONNECTOR WIRE IDENTIFICATION

Application		Wire Color
PCM Terminal No. 43
EGR Solenoid Sensor Ground Circuit		Black/Light Blue