Circuit Description
The powertrain control module (PCM) monitors the exhaust gas recirculation (EGR) valve pintle position input to ensure that the valve responds properly to commands from the PCM. The PCM compares the EGR position sensor parameter to the Desired EGR position parameter when the EGR valve is commanded closed. If the EGR position sensor indicates that the EGR valve is still open when the PCM is commanding the EGR valve closed, DTC P1404 will set.
Conditions for Running the DTC
| • | The ignition 1 signed parameter is between 11-18 volts. |
| • | The PCM has enabled the EGR valve. |
| • | The above conditions are met 3 times. |
Conditions for Setting the DTC
| • | The EGR position sensor parameter is 0.29 volts more than the EGR learned minimum position when the desired EGR position parameter is commanded to 0 percent for more than 2 seconds. |
| • | The EGR position sensor parameter is more than 30 percent and is steady for 2 seconds after a test failure and before the next test will be run. |
| • | The condition must be present 3 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. Refer to Exhaust Gas Recirculation Valve Replacement . |
| • | Inspect for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick. Refer to Exhaust Gas Recirculation (EGR) System Cleaning . |
| • | If the wiring condition 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 | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
Is the EGR position sensor parameter and the desired EGR position parameter within the specified value of each other? | 0.29 V | Go to Step 3 | Go to Step 4 | |
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 |
Does the test lamp turn ON at 10 percent and OFF at 0 percent when commanded with a scan tool? | -- | Go to Step 5 | Go to Step 13 |
5 | Observe the EGR position sensor parameter with a scan tool. Is the EGR position sensor parameter less than the specified value? | 1% | Go to Step 6 | Go to Step 9 |
6 | Measure the voltage from the 5-volt reference circuit of the EGR position sensor to the low reference circuit of the EGR position sensor with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage between the specified range? | 4.71-5.29 V | Go to Step 7 | Go to Step 8 |
7 | Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the EGR valve and the EGR valve position signal circuit. Is the EGR position sensor parameter more than the specified value? | 99% | Go to Step 14 | Go to Step 11 |
8 | Measure the voltage from the 5-volt reference circuit of the EGR position sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage within the specified range? | 4.71-5.29 V | Go to Step 10 | Go to Step 12 |
9 | 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 18 | Go to Step 15 |
10 | Test the low reference circuit of the EGR valve 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 18 | Go to Step 15 |
11 | Test the EGR valve position signal circuit for high resistance or 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 18 | Go to Step 15 |
12 | Test the 5-volt reference circuit of the EGR position sensor for an open, a short to ground, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 15 |
13 | Test the high control circuit of the EGR valve 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 18 | 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 Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 16 |
15 | Test for an intermittent and for a poor connection at the PCM. 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 18 | Go to Step 17 |
16 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- |
17 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- |
18 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 19 |
19 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
