P1406

This article has been updated with bulletin No. 71-65-36

DTC 1406 EGR VALVE PINTLE POSITION CIRCUIT















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 conditions will set the DTC:
^ EGR pintle position signal indicates a voltage out of the normal range of the pintle position sensor
^ Or signal that is 10% greater or less than the VCM commanded position
^ Ignition voltage greater than 9 volts

ACTION TAKEN WHEN DTC SETS
The VCM turns ON the MIL when P1406 is reported and 1 failure has occurred.

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 V 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.