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. When the ignition switch is turned ON, the ECM records the minimum value of the EGR valve position sensor which is the learned closed position. If the ECM detects a difference between the actual closed EGR position and the learned closed position of the EGR valve, DTC P1404 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1404 Exhaust Gas Recirculation (EGR) Closed Position Performance
Conditions for Running the DTC
| • | The ignition is ON, or the engine is operating. |
| • | The ignition 1 voltage is more 10 volts. |
| • | DTC P1404 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
The ECM detects the voltage on the control circuit of the EGR valve is low while the valve is not commanded or high while the valve is being commanded.
Actions 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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for a high resistance in the 5-volt reference or low reference circuit of the EGR valve.
-
This step tests for a high resistance in the signal circuit of the EGR valve.
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 | Is DTC P0404, P0405, P0406, or P1403 also set? | Go to Step 3 | ||||||
3 |
Is the voltage within the specified range? | 0.60-0.80 Volts | Go to Step 4 | Go to Step 5 | ||||
4 |
Did the DTC fail this ignition? | -- | Go to Step 5 | Go to Intermittent Conditions | ||||
Important: Use a test lamp that measures between 25-30 ohms. Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 6 | |||||
6 | 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 9 | Go to Step 8 | ||||
Is the parameter less than the specified value? | 0.05 Volts | Go to Step 11 | Go to Step 10 | |||||
8 | 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 15 | Go to Step 12 | ||||
9 | 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 15 | Go to Step 12 | ||||
10 | Test the signal 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 15 | Go to Step 12 | ||||
11 | Test the EGR valve for the following:
Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 | ||||
12 | 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 15 | Go to Step 14 | ||||
13 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||
14 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||
15 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 16 | ||||
16 | Are there any DTCs that have not been diagnosed? | -- | System OK | |||||
