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. This voltage varies depending on the position of the EGR valve. The ECM interprets this voltage as the position of the EGR valve. If the ECM detects a difference between the actual EGR position and the commanded EGR position, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0404 Exhaust Gas Recirculation (EGR) Open Position Performance
Conditions for Running the DTC
| • | DTCs P0112, P0113, P0405, P0406, and P0502 are not set. |
| • | The engine is operating. |
| • | The ignition voltage is between 11.7-16 volts. |
| • | The ambient air temperature is more than 3°C (37°F). |
| • | The desired EGR position is more than 0 percent and steady within 3 percent. |
| • | DTC P0404 runs continuously when the above conditions are met. |
Conditions for Setting the DTC
| • | The ECM detects a difference between the actual EGR position and the commanded EGR position of more than 15 percent for more than 30 seconds. |
| • | The above condition occurs 3 times with 5 seconds between each test. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the third 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 4 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
| • | Due to moisture associated with exhaust systems, the EGR valve may freeze and stick in cold weather at times. After the vehicle is brought into a warm shop for repairs, the valve warms and the condition disappears. By watching the actual EGR and desired EGR positions on a cold vehicle with a scan tool, the fault can be easily verified. Check the Freeze Frame data to determine if the DTC set when the vehicle was cold by viewing the engine coolant temperature (ECT). |
| • | For an intermittent condition, refer to Intermittent Conditions . |
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |||||||
2 | Is DTC P0405 or P0406 also set? | -- | Go to Step 3 | |||||||
3 |
Is the percentage less than the specified value? | 15% | Go to Step 4 | Go to Step 5 | ||||||
4 |
Did the DTC fail this ignition? | -- | Go to Step 5 | Go to Diagnostic Aids | ||||||
5 |
Observe the EGR Position Sensor parameter with a scan tool. Is the parameter less than the specified value? | 1% | Go to Step 6 | Go to Step 13 | ||||||
6 |
Important: Use the J 35616-200 Test Lamp Kit for this test. If the J 35616-200 is not available, use a test lamp that measures between 25-30 ohms. 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 8 | Go to Step 7 | ||||||
7 | Connect a test lamp between the 5-volt reference circuit of the EGR valve position sensor and a good ground. Does the test lamp illuminate? | -- | Go to Step 15 | Go to Step 14 | ||||||
8 |
Is the parameter more than the specified value? | 99% | Go to Step 9 | Go to Step 16 | ||||||
9 | Connect a test lamp between the ignition 1 voltage circuit of the EGR valve and a good ground. Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 20 | ||||||
10 |
Does the test lamp illuminate? | -- | Go to Step 11 | Go to Step 17 | ||||||
11 |
Is the resistance less than the specified value? | 3 ohms | Go to Step 12 | Go to Step 20 | ||||||
12 |
Is the voltage less than the specified value? | 0.5 V | Go to Step 18 | Go to Step 17 | ||||||
13 | Test the signal 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 23 | Go to Step 19 | ||||||
14 | Test the 5-volt 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 23 | Go to Step 19 | ||||||
15 | 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 23 | Go to Step 19 | ||||||
16 | Test the signal circuit of the EGR valve position sensor for the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 19 | ||||||
17 | Test the 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 23 | Go to Step 19 | ||||||
18 | Test the EGR valve for the following:
Did you find and correct the condition? | -- | Go to Step 23 | Go to Step 21 | ||||||
19 | Test for an intermittent and for a poor connection at the engine control module (ECM). 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 23 | Go to Step 22 | ||||||
20 | Repair the ignition 1 voltage circuit of the EGR valve for one of the following conditions:
Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 23 | -- | ||||||
21 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | -- | Go to Step 23 | -- | ||||||
22 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 23 | -- | ||||||
23 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 24 | ||||||
24 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||
