GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Optra 🢒 Engine 🢒 Engine Controls - 2.0L (L34 GMDAT) 🢒 DTC P0405

Circuit Description

The engine control module (ECM) monitors the position of the exhaust gas recirculation (EGR) valve through the EGR valve position sensor. The EGR valve position sensor sends a feedback voltage on the signal circuit to the ECM. The EGR position sensor voltage varies depending on the position of the EGR valve. If the voltage on the signal circuit of the EGR valve position sensor is less than a calibrated value, DTC P0405 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0405 Exhaust Gas Recirculation (EGR) Position Sensor Circuit Low Voltage

Conditions for Running the DTC
    • The ignition voltage is between 11.7-16 volts.
    • DTC P0405 runs continuously when the above condition is met.

Conditions for Setting the DTC

The ECM detects that the EGR position voltage is less than 0.2 volts for more than 10 seconds.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls 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
  1. Start the engine.
  2. Allow the engine to idle for 30 seconds.
  3. Observe the DTC Information with a scan tool.

Did DTC P0405 fail this ignition?

--

Go to Step 4

Go to Step 3

3

  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. 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
  1. Turn OFF the ignition.
  2. Disconnect the harness connector of the exhaust gas recirculation (EGR) valve.
  3. Turn ON the ignition, with the engine OFF.

    4. Important: Use the J 35616-200 Test Lamp Kit for this test. If the J 35616-200 is not available, use a test lamp that measures between 25-30 ohms.

  4. Connect a test lamp between the 5-volt reference circuit of the EGR valve position sensor and a good ground.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 5

5

While the test lamp is connected to the 5-volt reference circuit, disconnect the harness connector of the manifold absolute pressure (MAP) sensor.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 7

6
  1. Connect a 3-ampere fused jumper wire between the 5-volt reference circuit and the signal circuit of the EGR valve position sensor.
  2. Observe the EGR Position Sensor parameter with a scan tool.

Is the voltage more than the specified value?

4.9 V

Go to Step 9

Go to Step 8

7

Test the 5-volt reference circuit of the EGR valve position sensor for one of the following conditions:

    • An open
    • High resistance
    • A short to ground

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

8

Test the signal circuit of the EGR valve position sensor for the following conditions:

    • A short to ground
    • An open
    • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

9

Test for an intermittent and 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 14

Go to Step 12

10

Test for an intermittent and 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 14

Go to Step 13

11

Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 14

--

12

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

Did you complete the replacement?

--

Go to Step 14

--

13

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 14

--

14
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 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 15

15

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