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1999 Chrysler Concorde Error Code P0406: EGR Position Sensor Voltage Too High - Diagnosis and Fix

Model: 99 Chrysler Concorde Fault Code: P0406 Posted: 2006-08-21 10:33

Hi everyone, I'm encountering error code P0406 on my 1999 Chrysler Concorde with a 2.7L engine. The code indicates an issue with the EGR position sensor voltage — specifically, it's reporting 'voltage too high'. According to Chilton's manual, this means the EGR position sensor input is above the acceptable voltage range. I'm trying to determine whether the problem lies with the EGR position sensor itself or the EGR valve. Is it a purely electronic component or a vacuum-actuated one? How can I diagnose which part is faulty without replacing components prematurely? Any guidance on troubleshooting steps would be greatly appreciated.

Related fault codes
P0406
Comments (3)
Anonymous 2006-08-21 13:31

The EGR system in your 1999 Chrysler Concorde is likely an electronic valve, not vacuum-actuated. An electronic EGR valve consists of a complete electrical assembly with a sensor and actuator, while a vacuum-type would use a diaphragm and switch. Based on the vehicle's age and model, it's most probable that your system uses an electronic EGR valve. Could you confirm if your engine is a 2.7L V6? This helps narrow down compatibility issues.

Anonymous 2006-08-21 13:45

Thanks for clarifying! My vehicle does have the 2.7L V6 engine. As per Chilton's manual, error code P0409 (corrected to P0406) indicates that the EGR position sensor is reading an excessively high voltage — meaning it's outside the acceptable range. The manual doesn't specify troubleshooting steps, so I'm still unsure how to proceed. Should I start by testing the sensor resistance or checking for electrical faults? Any recommended diagnostic procedures would be very helpful.

Anonymous 2006-08-22 05:38

If the EGR position sensor is reading high voltage, it's often due to a faulty sensor or a stuck open EGR valve. A common fix in this case is replacing the EGR valve — especially if the system shows signs of performance issues like rough idling or increased emissions. However, before replacement, verify with a scan tool or multimeter to check for sensor voltage and resistance values to rule out a faulty sensor first.