Circuit Description
The PCM monitors the EGR valve pintle position input to ensure that the valve responds properly to commands from the PCM. When the ignition switch is turned ON, the PCM learns the EGR closed valve pintle position. The PCM compares the learned EGR closed valve pintle position to the Actual EGR position when the EGR valve is commanded closed. If the Actual EGR position 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
System voltage is above or equal to 10 volts.
Conditions for Setting the DTC
| • | EGR Feedback is 0.2 volt greater than the EGR Closed Valve Pintle Position when the Desired EGR Position is commanded to 0% |
| • | The above condition is present for around 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 and Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been 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 the scan tool. |
Diagnostic Aids
Check for the following condition(s):
| • | Excessive deposits on the EGR valve pintle or seat. |
| Remove the EGR valve and check for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick. |
| • | Poor connections at PCM or EGR valve. |
| Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the wiring appears to be OK, connect a J 39200 Digital Multimeter and check circuit continuity while moving connectors and wiring harnesses related to the EGR valve. A change in the DMM display will indicate the location of the malfunction. |
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table:
-
Verifies that the malfunction is present.
-
If DTC P1404 will only set under certain conditions, the malfunction may be intermittent; refer to DTC P1404 Diagnostic Aids. If an intermittent wiring problem is not present, check for a poor connection at the PCM or the EGR valve. If the connections are OK and DTC P1404 continues to set, replace the EGR valve.
-
This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
|
Important: If DTC P0403 is set, diagnose that other DTC first. With a scan tool and the engine idling, observe Actual EGR Position parameter. Does the scan tool indicate Actual EGR Position at the specified value? | 0% | |||||||||
Does the Desired EGR Position remain close to Actual EGR Position at all commanded positions? | -- | |||||||||
Does the scan tool indicate DTC P1404 failed this ignition? | -- | Go to Diagnostic Aids | ||||||||
5 |
Does the scan tool indicate Actual EGR Position at the specified value? | 0% | ||||||||
6 | Probe the EGR pintle position sensor ground circuit using a J 35616-200 Test Lamp that is connected to B+. Does the test lamp illuminate? | -- | ||||||||
7 |
Does the voltage measure at or near the specified value? | 0V | ||||||||
8 | Test the EGR pintle position sensor ground circuit for an open. Refer to Wiring Repairs . Did you find and correct the condition? | -- | ||||||||
9 | Inspect for faulty connections at the EGR valve. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs . Did you find and correct the condition? | -- | ||||||||
10 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Notice: If the EGR valve shows signs of excessive heat, inspect the exhaust
system for blockage--possibly a plugged converter--using the procedure
found on the Restricted Exhaust System Check. If the exhaust system is restricted,
repair the cause. Inspect for an open injector caused by one or more of the
following conditions:
Did you find and correct the condition? | -- | -- | |||||||
11 | Repair short to voltage in the EGR pintle position signal circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | -- | |||||||
12 |
Did you find and correct the condition? | -- | ||||||||
13 | Inspect the circuits related to the EGR valve for faulty connections at the PCM. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs . Did you find and correct the condition? | -- | ||||||||
|
Important: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Did you complete the replacement? | -- | -- | ||||||||
15 |
Does the DTC reset? | -- | System OK |
