GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2003 🢒 L300/LW300 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 DTC P0403

Object Number: 896244 Size: MF

Circuit Description

The engine control module (ECM) controls the exhaust gas recirculation (EGR) valve with a solid state device called a driver. The driver supplies the EGR solenoid with a ground that is pulse width modulated (PWM) through the EGR solenoid control circuit. 12 volts are provided by the Engine CNTL 1 fuse through the ignition positive voltage circuit. The ECM uses a pull-up voltage of 2.6-4.6 volts to determine if a circuit is open, shorted to ground or shorted to voltage. If the ECM detects a pull-up voltage between 2.6-4.6 volts with the EGR not commanded, indicating an open circuit, DTC P0403 sets.

Conditions for Running the DTC
    • The engine speed is more than 40 RPM
    • The ignition voltage is between 7.5-15 volts.
    • The EGR valve is not commanded to open.

Conditions for Setting the DTC
    • The ECM detects an open in the control circuit of the EGR solenoid or the battery positive voltage circuit of the EGR solenoid.
    • The above condition is met for more than 0.5 seconds.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Important: The exhaust gas recirculation (EGR) valve pintle may not move until more than 40 percent duty cycle is applied.

  1. Turn ON the ignition, with the engine OFF.
  2. Command the EGR duty cycle to 100 percent while observing the EGR Sensor parameter with a scan tool.
  3. Exit the EGR output control function.

Did the EGR Sensor parameter read more than 4 volts when commanded with a scan tool?

Go to Step 3

Go to Step 4

3
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 90 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 4

Go to Intermittent Conditions

4

Notice: Refer to Test Probe Notice in the Preface section.

  1. Turn OFF the ignition.
  2. Disconnect the EGR valve.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the ignition positive voltage circuit of the EGR valve, at the harness connector, and a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 6

5
  1. Connect a test lamp between the battery positive voltage circuit of the EGR solenoid, at the harness connector, and the control circuit of the EGR solenoid, at the harness connector.
  2. Command the EGR duty cycle to 50 percent with a scan tool.

Does the test lamp illuminate when commanded with a scan tool?

Go to Step 8

Go to Step 7

6

Test the ignition positive voltage circuit of the EGR solenoid for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

--

7

Test the control circuit of the EGR solenoid for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 9

8

Test for an intermittent and for a poor connection at the EGR valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

9

Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 11

10

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

Did you complete the replacement?

Go to Step 12

--

11

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 12

--

12
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 90 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 13

13

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK