Circuit Description
The powertrain control module (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 monitors 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
| • | None of the following DTCs are set: |
| - | Throttle position (TP) sensor |
| - | Vehicle speed sensor (VSS) |
| - | Misfire |
| - | Intake air temperature (IAT) sensor |
| - | Manifold absolute pressure (MAP) sensor |
| - | Idle speed |
| - | Fuel injector |
| - | Engine coolant temperature (ECT) sensor |
| - | Crankshaft position (CKP) sensor |
| - | Mass air flow (MAF) sensor |
| • | The system voltage is between 9 and 16 volts. |
Conditions for Setting the DTC
| • | The EGR feedback is 0.4 volt more than the EGR closed valve pintle position when the Desired EGR Position is commanded to 0 percent. |
| • | The above conditions have to be present twice for VIN K and 4 times for VIN 1. |
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
Check for the following conditions:
| • | 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. |
| • | A faulty connection at the PCM or the EGR valve--Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. |
| • | Inspect the wiring harness for damage. If the wiring appears to be OK, connect a digital multimeter (DMM) and check the circuit continuity while moving the connectors and wiring harnesses related to the EGR valve. A change in the DMM display will indicate the location of the malfunction. |
Test Description
The numbers below refer to the step numbers 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 faulty 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 replaced, the new PCM must be programmed.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On Board Diagnostic (OBD) System Check performed? | -- | ||||||
|
Important: If DTC P1635 5 Volt Reference Circuit is set, perform that diagnostic first. Then if DTC P0403 Exhaust Gas Recirculation (EGR) Solenoid Control Circuit is set, perform that diagnostic. With the engine idling, observe the Actual EGR Position display on the scan tool. Is the Actual EGR Position equal to the specified value? | 0 percent | |||||||
Does the Desired EGR Position remain close to the Actual EGR Position at all commanded positions? | -- | |||||||
Does the scan tool indicate DTC P1404 failed this ign? | -- | Go to Diagnostic Aids | ||||||
5 |
Is the Actual EGR Position equal to the specified value? | 0 percent | ||||||
6 | Probe the EGR pintle position sensor ground circuit at the EGR valve harness connector with a test lamp connected to B+. Does the test lamp illuminate? | -- | ||||||
7 |
Is the voltage approximately equal to the specified value? | 0 V | ||||||
8 |
Was a problem found? | -- | ||||||
9 |
Was a problem found? | -- | ||||||
10 |
Notice: In order to prevent further damage if the EGR valve shows signs of excessive
heat, check 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; one of which might be an injector
which is open due to one of the following reasons:
Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the repair? | -- | -- | |||||
11 | Locate and repair a short to voltage in the EGR pintle position signal circuit. Refer to Wiring Repairs in Wiring Systems . Did you complete the repair? | -- | -- | |||||
12 |
Was a problem found? | -- | ||||||
|
Important:: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the repair? | -- | -- | ||||||
14 |
Does the scan tool indicate DTC P1404 failed this ignition? | -- | System OK |
