DTC P1404 Exhaust Gas Recirculation (EGR) Closed Position Performance. Buick LeSabre 2000

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2000 🢒 LeSabre 🢒 DTC 🢒 DTC P1404 Exhaust Gas Recirculation (EGR) Closed Position Performance

Engine Controls Components
Secondary Air Bypass Valve, EGR Valve
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

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

•	No TP, VSS, Misfire, IAT, MAP, Idle Speed, Fuel Injector, ECT, CKP, or MAF sensor DTCs set.

•	System voltage is between 9 volts and 16 volts.

Conditions for Setting the DTC

•	EGR Feedback is 0.4 volt more than the EGR Closed Valve Pintle Position when the Desired EGR Position is commanded to 0.0 percent

•	The above condition is present twice.

Action Taken When the DTC Sets

•	The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.

•	The PCM disables the EGR for the ignition cycle

•	The PCM stores the conditions that were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC

•	The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic runs and passes.

•	The history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction.

•	The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.

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.

•	Faulty 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. Use a corresponding mating terminal to test for correct terminal tension.

•	A damaged harness--Inspect the wiring harness for damage. If the wiring appears to be OK, connect DMM 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

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 poor connection at the PCM or the EGR valve. If the connections are OK and DTC P1404 continues to set, replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement .

his vehicle is equipped with a PCM that utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.

DTC P1404 - EGR Valve Stuck Open

Step

Action

Values

Yes

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Important: If DTC P0403 is set, diagnose DTC P0403 Exhaust Gas Recirculation (EGR) Solenoid Control Circuit first.

With the engine idling, observe the Actual EGR Position display on the scan tool.

Is the Actual EGR Position at the specified value?

0 percent

Go to Step 3

Go to Step 5

Turn the ignition ON, with the engine OFF.
Select the scan tool EGR valve output control function.
Increment the EGR valve through all positions while comparing the Desired EGR Position to the Actual EGR Position.

Does the Desired EGR Position remain close to the Actual EGR Position at all of the commanded positions?

Go to Step 4

Go to Step 6

Review and record the scan tool Fail Records data.
Operate the vehicle within Fail Records conditions.
Using a scan tool, monitor the Specific DTC info for DTC P1404 until the DTC P1404 test runs.

Does the scan tool indicate DTC P1404 failed this ignition?

Go to Step 5

Go to Diagnostic Aids

Disconnect the EGR valve electrical connector.
Observe the Actual EGR Position on the scan tool.

Is the Actual EGR Position at the specified value?

0 percent

Go to Step 6

Go to Step 7

Probe the EGR pintle position sensor ground circuit at the EGR valve harness connector with a test lamp to B+.

Is the test lamp ON?

Go to Step 9

Go to Step 8

Turn the ignition OFF.
Disconnect the PCM.
Turn the ignition ON, with the engine OFF.
Measure voltage between the EGR valve pintle position signal circuit and a known good ground.

Is the measured voltage near the specified value?

0 V

Go to Step 13

Go to Step 11

Check the EGR pintle position sensor ground circuit for an open between the PCM and the EGR valve.
If a problem is found, repair as necessary. Refer to Wiring Repairs .

Was a problem found?

Go to Step 14

Go to Step 12

Check for poor terminal connections at the EGR valve.
If a problem is found, repair as necessary. Refer to the following procedures:

•	Testing for Continuity

•	Repairing Connector Terminals

•	Connector Repairs in Wiring Systems.

Was a problem found?

Go to Step 14

Go to Step 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:

•

Stuck

•	Grounded driver circuit

Check the oil for possible fuel contamination if a stuck open fuel injector is found.

Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement .

Is action complete?

Go to Step 14

Locate and repair the short to voltage in the EGR pintle position signal circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

Go to Step 14

Check the circuits related to the EGR valve for faulty terminal connections at the PCM.
If a problem is found, repair as necessary. Refer to the following procedures:

•	Testing for Continuity

•	Repairing Connector Terminals

•	Connector Repairs in Wiring Systems.

Was a problem found?

Go to Step 14

Go to Step 13

Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Replace the PCM.

Is the action complete?

Go to Step 14

Review and record the scan tool Fail Records data.
Clear the DTCs.
Operate the vehicle within the Fail Records conditions.
Using a scan tool, monitor the Specific DTC info for DTC P1404.

Does the scan tool indicate DTC P1404 failed this ignition?

Go to Step 2

System OK