Circuit Description
The PCM monitors the EGR valve pintle position input to ensure that the valve responds properly to the PCM commands. The PCM compares the actual EGR position with the desired EGR position when the valve is commanded open. If the actual EGR Position varies more than 15 percent from the desired EGR position when the PCM commands the EGR valve open, DTC P0404 will set.
Conditions for Running the DTC
The system voltage is between 10 volts and 16 volts.
Conditions for Setting the DTC
| • | The desired EGR does not equal 0. |
| • | The actual EGR position varies more than 15 percent from the desired EGR position. |
| • | The above conditions are present for more than 20 seconds. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
Inspect for the following conditions:
| • | Excessive deposits on the EGR pintle or seat. |
| • | Remove the EGR valve and inspect for deposits that can interfere with the EGR valve pintle extending completely or for conditions that can cause the pintle to stick. |
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Test Description
The numbers below refer to the step numbers on the Diagnostic Table:
-
This step verifies that the malfunction is present.
-
If DTC P0404 will only set during certain conditions, the malfunction may be intermittent. Refer to Diagnostic Aids. If there is no intermittent wiring problem, check for a poor connection at the PCM or at the the EGR valve. If the connections are OK and DTC P0404 continues to set, replace the EGR valve.
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This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read only memory (EEPROM). When you replace the PCM, you mustg program the new PCM.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||
|
Important: : If any of the following DTCs are set, diagnose the other DTC first.
Does the desired EGR Position remain close to the actual EGR Position at all commanded positions? | -- | |||||||
Does the scan tool indicate that DTC P0404 failed this ignition? | -- | Go to Diagnostic Aids | ||||||
4 |
Is the voltage at the specified value? | 5 V | ||||||
5 | Probe the EGR pintle position signal circuit at the EGR valve harness connector with a J 35616-200 test lamp connected to battery positive voltage. Is the test lamp on? | -- | ||||||
6 |
Is the actual EGR position at the specified value? | 100% | ||||||
7 |
Did you find a problem? | -- | ||||||
8 |
Is the test lamp on? | -- | ||||||
9 |
Did you find a problem? | -- | ||||||
10 |
Did you find a problem? | -- | ||||||
11 |
Did you find a problem? | -- | ||||||
12 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Is the action complete? | -- | -- | |||||
13 | Locate and correct the short to ground in the EGR pintle position signal circuit. Refer to Wiring Repairs . Is the action complete? | -- | -- | |||||
14 |
Did you find a problem? | -- | ||||||
15 |
Did you find a problem? | -- | ||||||
|
Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .Is the action complete? | -- | -- | ||||||
17 |
Does the scan tool indicate that DTC P0404 failed this ignition? | -- | System OK |
