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 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
| • | No TP, VSS, misfire, IAT, MAP, idle speed, fuel injector, ECT, CKP, or MAF sensor DTCs set. |
| - | Throttle position (TP) sensor DTCs |
| - | Vehicle speed sensor (VSS) DTCs |
| - | Intake air temperature (IAT) sensor DTCs |
| - | Manifold absolute pressure (MAP) sensor DTCs |
| - | Engine coolant temperature (ECT) sensor DTCs |
| - | Crankshaft position (CKP) sensor DTCs |
| - | Mass air flow (MAF) sensor DTCs |
| - | Fuel injector DTCs |
| - | Idle speed DTCs |
| - | Misfire DTCs |
| • | The IAT is more than -10°C (14°F). |
| • | The proper engine run time is achieved. The length of time ranges from 20 seconds to 6 minutes depending upon engine coolant temperature at startup. |
| • | The throttle position is more than 2 percent. |
| • | The vehicle speed is more than 2 mph. |
| • | The system voltage is between 10 and 16 volts. |
Conditions for Setting the DTC
| • | The EGR feedback is 0.2 volts more than the EGR closed valve pintle position when the desired EGR position is commanded to 0 percent. |
| • | The above condition is present for longer than 20 seconds. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the first 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 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:
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.
-
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, inspect 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 powertrain control module (PCM) which utilizes an electrically erasable programmable read-only memory (EEPROM). When the PCM is 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? | -- | ||||||
|
Important: : If DTC P0403 is set, diagnose that DTC first. Refer to DTC P0403 Exhaust Gas Recirculation (EGR) Solenoid Control Circuit . With the engine idling, observe the actual EGR position display on the scan tool. Does the actual EGR position equal the specified value? | 0 % | |||||||
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 ignition? | -- | Go to Diagnostic Aids | ||||||
5 |
Does the Actual EGR Position equal the specified value? | 0% | ||||||
6 | Probe the EGR pintle position sensor ground circuit at the EGR valve harness connector with a test lamp connected to battery positive voltage. Does the test lamp illuminate? | -- | ||||||
7 |
Is the voltage near the specified value? | 0.0 V | ||||||
8 | Test the EGR pintle position sensor ground circuit for an open between the PCM and the EGR valve. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | ||||||
9 | If a problem is found, repair as necessary. Inspect for faulty terminal connections at the EGR valve. Refer to Testing for Continuity or Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you complete the repair? | -- | ||||||
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 replacement? | -- | -- | |||||
11 | Locate and repair short to voltage in the EGR pintle position signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||
12 |
Did you complete the repair? | -- | ||||||
13 |
Did you complete the repair? | -- | ||||||
|
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 scan tool indicate DTC P1404 Failed this ignition? | -- | System OK |
