Circuit Description
The engine control module (ECM) monitors the position of the exhaust gas recirculation (EGR) valve through the EGR valve position sensor. The EGR valve position sensor sends a feedback voltage on the signal circuit to the ECM. The EGR position sensor voltage varies depending on the position of the EGR valve. If the voltage on the signal circuit of the EGR valve position sensor is pulled higher than a calibrated value, DTC P0406 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0406 Exhaust Gas Recirculation (EGR) Position Sensor Circuit High Voltage
Conditions for Running the DTC
| • | The ignition is ON or the engine is operating. |
| • | DTC P0406 runs continuously once the above condition is met. |
Conditions for Setting the DTC
The ECM detects that the EGR position voltage is more than 4.99 volts for more than 1 second.
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate after 3 consecutive trips with a fail. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||||||||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |||||||||
2 |
Did DTC P0406 fail this ignition? | -- | Go to Step 4 | Go to Step 3 | ||||||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions | ||||||||
4 |
Is the voltage less than the specified value? | 5.2 V | Go to Step 5 | Go to Step 8 | ||||||||
5 |
Important: Use a test lamp that measures between 25-30 ohms for this test. Connect a test lamp between the 5-volt reference circuit and the low reference circuit of the EGR valve position sensor. Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 11 | ||||||||
6 | Measure the voltage between the signal circuit of the EGR valve position sensor and a good ground. Is the voltage less than the specified value? | 5 V | Go to Step 7 | Go to Step 10 | ||||||||
7 |
Is the parameter less than the specified value? | 0.05 V | Go to Step 12 | Go to Step 10 | ||||||||
8 | Test the 5-volt reference circuit of the following sensors for a short to voltage:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 9 | ||||||||
9 | Test the 5-volt reference circuit of the EGR valve position sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 | ||||||||
10 | Test the signal circuit of the EGR valve position sensor for one of the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 | ||||||||
11 | Test the low reference circuit of the EGR valve position sensor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 | ||||||||
12 | Test for an intermittent and poor connection at the EGR valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 | ||||||||
13 | Test for an intermittent and poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 | ||||||||
14 | Replace the EGR valve. Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||||
15 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||||
16 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 17 | ||||||||
17 | Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||
