Part 1 of 2

DTC P1406 Exhaust Gas Recirculation (EGR) System Pintle Position Error (Part 1 Of 2):

Exhaust Gas Recirculation (EGR):

CIRCUIT DESCRIPTION
The Vehicle Control Module-A (VCM-A) constantly monitors the linear Exhaust Gas Recirculation (EGR) valve pintle position sensor to ensure that the valve is responding properly to commands from the VCM-A. DTC P1406 is a type "B" DTC.

DTC P1406 WILL SET WHEN
^ EGR pintle position signal indicates a voltage out of the normal range of the pintle position sensor, or a signal that is 20% greater or less than the VCM-A commanded position for 10 seconds.
^ Ignition voltage greater than 9 V.

ACTION TAKEN (VCM-A WILL DEFAULT TO)
If a current DTC P1406 sets during two consecutive test cycles, the VCM-A will turn "ON" the Malfunction Indicator Lamp (MIL) (Service Engine Soon).

DTC P1406 WILL CLEAR WHEN
The VCM-A will turn the MIL "OFF" after three consecutive trips without a fault condition present. A history DTC will be cleared if no fault conditions have been detected for forty warm-up cycles [coolant temperature has risen 22°C (40°F) from start-up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle] or the Tech 1 clearing feature has been used.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks for an EGR valve sticking partially open or an incorrect pintle position sensor feedback signal.
2. Ensures that the VCM-A is capable of controlling EGR pintle position and is reading the pintle position feedback signal properly.
3. Checks the EGR valve driver in the VCM-A and CKT 435.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation.

Check for:
^ Poor connection or damaged harness - Inspect VCM-A harness connectors for backed out terminals "BL18", "GR27", "GR19", or "RE10", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and 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.