P1406

DTC P1406 EXHAUST GAS RECIRCULATION (EGR) POSITION SENSOR PERFORMANCE






























Circuit Description
The VCM constantly monitors the linear EGR valve pintle position sensor in order to ensure that the valve is responding properly to the commands from the VCM. The DTC P1406 is a type A DTC.

Conditions for Setting the DTC
The following condition will set the DTC:
• Ignition voltage greater than 9 volts
• The difference between the actual EGR position and the desired EGR position is greater than 10% for 10 seconds

Action Taken When DTC Sets
If a current DTC P1406 sets during 2 consecutive test cycles, the VCM turns ON the MIL.

Conditions for Clearing the MIL/DTC
The VCM turns OFF the MIL after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle) or the scan tool clearing feature has been used.

Diagnostic Aids
A poor connection or rubbed-through wire insulation may cause an intermittent. Check for the following conditions:

• Poor connection or damaged harness - Inspect VCM harness connectors for backed out terminals at EGR Control signal circuit, 5 Volt reference circuit, EGR sensor ground circuit, or Pintle position circuit for the following items:
• Improper mating
• Broken locks
• Improperly formed or damaged terminals
• Poor terminal to wire connection
• Damaged harness

Intermittent test - If connections and harness check OK, monitor a digital voltmeter connected between affected terminals and ground while moving related connectors and wiring harness. If the failure is induced, the voltage reading will change.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. Checks for an EGR valve sticking partially open or an incorrect pintle position sensor feedback signal.
3. This step determines if this DTC was set during an intermittent condition. If the fault that set this DTC is not present, check for other stored DTCs.
5. Checks the EGR valve driver in the VCM and the EGR Control circuit.
6. This checks for EGR Valve Ignition Feed at the EGR valve.
38. Clearing the DTC Information is a very important step in this diagnostic. This allows the EGR Valve to relearn a new minimum pintle position.