Circuit Description
The exhaust gas recirculation (EGR) valve position sensor is monitored by the powertrain control module (PCM). The 5-volt reference circuit, low reference circuit and the EGR valve position signal circuit are used by the PCM to determine the EGR valve position. When the ignition switch is turned ON, the PCM records the EGR Learned Minimum Position. The PCM compares the EGR Learned Minimum Position parameter to the EGR Position Sensor parameter. If the PCM detects that the EGR valve is still open when the PCM is commanding the EGR valve closed, DTC P1404 sets.
Conditions for Running the DTC
| • | The engine is running. |
| • | The Ignition 1 Signal voltage parameter is more than 11 volts. |
| • | The EGR command will be disabled if the start-up ECT is less than 5°C (41°F) and will not enable until the ECT is more than 75°C (167°F). |
| • | The EGR valve is commanded to 0 percent for 20 seconds after the EGR valve has been commanded to open more than 40 percent for 0.5 seconds. |
| • | The EGR flow test is not running. |
Conditions for Setting the DTC
| • | The EGR Position Sensor parameter is 0.23 volt more than the EGR Learned Minimum Position parameter when the Desired EGR Position parameter is commanded to 0 percent for 20 seconds. |
| • | The EGR Position Sensor parameter is more than 40 percent and is steady for 0.5 seconds after a test failure and before the next test will be run. |
| • | The above conditions are met 4 times. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | Inspect for excessive deposits on the EGR valve pintle or seat. Remove the EGR valve and check for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick. |
| • | If the problem is intermittent, refer to Intermittent Conditions . |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Is DTC P0641 also set? | -- | Go to DTC P0641 | Go to Step 3 |
Is the EGR Position Sensor parameter less than the specified value? | 1% | Go to Step 4 | Go to Step 6 | |
4 |
Is the EGR Position Variance parameter less than the specified value? | 15% | Go to Step 5 | Go to Step 7 |
5 |
Did the DTC fail this ignition? | -- | Go to Step 6 | Go to Diagnostic Aids |
6 |
Is the EGR Position Sensor parameter less than the specified value? | 1% | Go to Step 7 | Go to Step 10 |
7 | Connect a test lamp between the 5-volt reference circuit of the EGR valve and the low reference circuit of the EGR valve. Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 9 |
8 | Connect a 3-amp fused jumper wire from the 5-volt reference circuit of the EGR valve to the EGR valve position signal circuit. Is the EGR Position Sensor parameter on the scan tool more than the specified value? | 99% | Go to Step 14 | Go to Step 12 |
9 | Connect a test lamp between the 5-volt reference circuit of the EGR valve and a good ground. Does the test lamp illuminate? | -- | Go to Step 11 | Go to Step 13 |
10 | Test the EGR valve position signal circuit 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 19 | Go to Step 16 |
11 | Test the low reference circuit of the EGR valve for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 16 |
12 | Test the EGR valve position signal circuit for high resistance or for a high resistance short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 16 |
13 | Test the 5-volt reference circuit of the EGR valve for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 15 |
14 | Test for an intermittent and for a poor connection at the EGR valve. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 17 |
15 | Test all 5-volt reference circuits 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 19 | Go to Step 16 |
16 | Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 18 |
17 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- |
18 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- |
19 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 20 |
20 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
