Circuit Description
In order to control the exhaust gas recirculation (EGR), the control module operates the linear EGR valve. The linear EGR valve is a small motor with a pintle that is normally closed. By providing a ground path, the control module will open the pintle and allow the exhaust gasses to pass through the valve. The control module of the EGR is based on the following inputs:
| • | The engine coolant temperature - above 25°C. |
| • | The TP OFF idle |
| • | MAP |
| • | BARO |
| • | Park/Neutral position |
| • | The pintle position sensor. |
If DTC P0401 or P1406 is stored, refer to the applicable DTC table. This chart is used for a malfunctioning valve, plugged EGR passages, or improper wiring connections.
An intermittent may be caused by any of the following conditions:
| • | A poor connection |
| • | Rubbed through wire insulation |
| • | A broken wire inside the insulation |
Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Test Description
The numbers below refer to the step numbers in the diagnostic table.
-
At idle, the EGR valve should not be open more than 0 percent.
-
This step checks the ability of the pintle to be manually commanded to the desired positions.
-
This step checks the electrical circuit for a short to voltage.
-
This step checks the electrical control circuits from the VCM to the EGR valve.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
Does the scan tool indicate more than the specified value? | 0% | |||||||||
Does the actual EGR position follow the commanded EGR position? | 100% | |||||||||
4 | Disconnect the EGR valve harness connector. Does the scan tool indicate the actual EGR position above the specified value? | 0% | ||||||||
Is the test lamp ON? | -- | |||||||||
Is the test lamp ON? | 100% | |||||||||
7 |
Is the test lamp ON? | -- | ||||||||
8 | Check the EGR valve feed control circuit for an open. Did you find a problem? | -- | ||||||||
9 | Check the EGR valve ground circuit for the following conditions:
Did you find a problem? | -- | ||||||||
10 |
Is the voltage above the specified value? | 5.2 V | ||||||||
11 |
Is the test lamp ON? | -- | ||||||||
12 |
Did you find a problem? | -- | ||||||||
13 |
Is the voltage near the specified value? | 5.2 V | ||||||||
14 |
Is the actual EGR position near the specified value? | 100% | ||||||||
15 |
Did you find a problem? | -- | ||||||||
16 |
Did you find a problem? | -- | ||||||||
17 |
Does the MAP sensor reading go higher? | 30% | ||||||||
18 | Repair the blockage in the EGR valve passages. Is the action complete? | -- | -- | |||||||
19 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Is the action complete? | -- | -- | |||||||
20 | Check the EGR pintle position circuit for an open or short to ground. Did you find a problem? | -- | ||||||||
21 | Check for a poor connection at the VCM connectors. Did you find a problem? | -- | ||||||||
22 | Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||
23 |
Program the new VCM. Refer to VCM Replacement/Programming . Is the action complete? | -- | -- | |||||||
24 |
Does the actual EGR position follow the commanded EGR position? | -- | System OK |
