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 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 (160°F) that same ignition cycle. |
| • | Use of a Scan Tool |
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 ± .4 volt. A DTC P0406 will result if the ground circuit is open. If DTC P0406 is intermittent.
Test Description
Number(s) below refer to the Step number(s) on the Diagnostic Table.
-
This Step will check for EGR Vent Solenoid DTC.
-
This Step determines if DTC P0406 is a hard failure or an intermittent condition.
-
This Step simulates conditions for a DTC P0405. If the PCM recognizes the change, the PCM and the signal circuit are OK.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing DTCs use the scan tool Capture Info to record freeze frame and failure records for reference, as data will be lost when Clear Info function is used. Was the On-Board Diagnostic (OBD) System Check performed? | -- | ||
Is DTC P1653 set? | -- | Go to the Applicable DTC Table | ||
Does the scan tool display EGR Sensor voltage greater than the specified value? | 4.0 V | |||
Does the scan tool display a EGR Sensor voltage less than the specified value? | 1.0 V | |||
5 | DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs are stored refer to those chart(s) first. Are additional DTCs stored? | -- | Go to the Applicable DTC Table | Go to Diagnostic Aids |
6 |
Is voltage greater than the specified value? | 5.2V | ||
7 | Probe the EGR Control Pressure/Baro sensor ground circuit with a test light to B+. Is the test light ON? | -- | ||
8 | Check the EGR vacuum source for a restriction. Was a problem found? | -- | ||
9 | Replace the faulty EGR Control Pressure/Baro sensor. Refer to Exhaust Gas Recirculation Control Pressure Sensor Replacement . Is the action complete? | -- | -- | |
10 | Check for a short to voltage in the sensor signal circuit. Was a problem found? | -- | ||
11 |
Was a repair performed? | -- | ||
12 | Repair the open in the sensor ground circuit. Is the action complete? | -- | -- | |
13 | Repair as necessary. Is the action complete? | -- | -- | |
14 | Replace the faulty PCM. Important: If the PCM is faulty, the new PCM must be programmed. Go to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |
15 |
Does the Scan Tool indicate that this diagnostic Ran and Passed? | -- | ||
16 | Using the Scan Tool, select Capture Info, Review Info. Are any DTCs displayed that have not been diagnosed? | -- | Go to the Applicable DTC Table | System OK |
