Circuit Description
The powertrain control module (PCM) monitors the EGR position sensor parameter of the exhaust gas recirculation (EGR) valve to ensure that the valve responds properly to commands from the PCM. The PCM compares the EGR position sensor parameter with the desired EGR position parameter when the valve is commanded open. If the PCM detects a difference of 12 percent between the EGR position sensor parameter and desired EGR position parameter for a calibrated amount of time, DTC P0404 will set.
Conditions for Running the DTC
| • | The ignition 1 signal parameter is between 11-18 volts. |
| • | The EGR valve is commanded open. |
Conditions for Setting the DTC
| • | The difference between the desired EGR position parameter and the EGR position sensor parameter is more than 12 percent. |
| • | The condition is present for more than 10 seconds. |
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 pintle or seat. Remove the EGR valve. Refer to Exhaust Gas Recirculation Pipe Replacement . |
| • | Inspect for deposits that may interfere with the EGR valve pintle extending completely or may cause the pintle to stick. Refer to Exhaust Gas Recirculation (EGR) System Cleaning . |
| • | If the condition is intermittent, refer to Intermittent Conditions . |
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-Engine Controls? | -- | Go to Step 2 | |||||||
2 |
Does the EGR position sensor parameter remain within 12 percent of the desired EGR position parameter when commanded with a scan tool? | -- | Go to Step 3 | Go to Step 4 | ||||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids | ||||||
4 | 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 7 | Go to Step 5 | ||||||
5 |
Is the EGR position sensor parameter less than the specified value? | 1% | Go to Step 6 | Go to Step 16 | ||||||
6 |
Does the test lamp turn ON at 10 percent and OFF at 0 percent when commanded with a scan tool? | -- | Go to Step 10 | Go to Step 9 | ||||||
7 |
Does the test lamp turn ON at 10 percent and OFF at 0 percent when commanded with a scan tool? | Go to Step 8 | Go to Step 9 | |||||||
8 |
Does the test lamp turn ON at 10 percent and OFF at 0 percent when commanded with a scan tool? | -- | Go to Step 20 | Go to Step 15 | ||||||
9 | Does the test lamp remain illuminated when commanded to 0 percent with a scan tool? | -- | Go to Step 14 | Go to Step 13 | ||||||
10 | 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 11 | Go to Step 12 | ||||||
11 | 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 20 | Go to Step 18 | ||||||
12 | 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 17 | Go to Step 19 | ||||||
13 | Test the high control circuit of the EGR valve for the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 24 | Go to Step 21 | ||||||
14 | 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 24 | Go to Step 21 | ||||||
15 | Test the low control 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 24 | Go to Step 21 | ||||||
16 | 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 24 | Go to Step 21 | ||||||
17 | 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 24 | Go to Step 21 | ||||||
18 | 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 24 | Go to Step 21 | ||||||
19 | Test the 5-volt reference circuit of the EGR valve for the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 24 | Go to Step 21 | ||||||
20 | 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 24 | Go to Step 22 | ||||||
21 | Test for an intermittent and for a poor connection at the 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 24 | Go to Step 23 | ||||||
22 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | -- | Go to Step 24 | -- | ||||||
23 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 24 | -- | ||||||
24 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 25 | ||||||
25 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||
