P0406

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
A EGR Control Pressure/Baro sensor is used to monitor the amount of vacuum in the EGR circuit. It senses the actual vacuum in the EGR vacuum line and sends a signal back to the Powertrain Control Module (PCM). This signal is used to control EGR duty cycle calculated by the PCM. This is a type B DTC.

CONDITIONS FOR SETTING THE DTC
- Actual EGR greater than or equal to 3.96 volts (85 kPa).
- Desired EGR is less than or equal to 60 kPa.
- EGR vent is closed.
- Conditions met for 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
PCM will shut off EGR system.

CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM will turn the MIL off after three consecutive trips without a fault condition.
- A History DTC will clear when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (16O°F) that same ignition cycle.

DIAGNOSTIC AIDS
With the ignition ON and the engine stopped, the manifold pressure is equal to atmospheric pressure with the signal voltage being high. This information is used by the PCM as an indicator of vehicle altitude. Comparison of the reading with a known good vehicle with the same sensor is a good way to check accuracy of a "suspect" sensor. Readings should be the same + 0.4 volt. A DTC P0406 will result if the ground circuit is open. If DTC P0406 is intermittent, refer to Symptoms. Testing and Inspection

TEST DESCRIPTION
Number(s) below refer to the Step number(s) on the Diagnostic Table.

2. This Step will check for EGR Vent Solenoid DTC.
3. This Step determines if DTC P0406 is a hard failure or an intermittent condition.
4. This Step simulates conditions for a DTC P0405. If the PCM recognizes the change, the PCM and the signal circuit are OK.