2001 Chevrolet/Geo Camaro  

DTC P0404

Circuit Description

The powertrain control module (PCM) monitors the exhaust gas recirculation (EGR) valve pintle position input in order to ensure that the valve responds properly to commands from the PCM. The PCM compares the EGR position sensor with desired EGR position when the valve is commanded open. If the difference between the EGR position sensor and desired EGR position is more than 15 percent this diagnostic trouble code (DTC) will set.

Conditions for Running the DTC

The system voltage is greater than 10 volts.

The EGR valve is enabled.

Conditions for Setting the DTC
Action Taken When the DTC Sets
Conditions for Clearing the MIL/DTC
Diagnostic Aids

Inspect for the following conditions:

Excessive deposits on the EGR pintle or seat--Remove the EGR valve, and inspect for deposits that may interfere with the EGR valve pintle extending completely or may cause the pintle to stick.

If the condition is intermittent, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table:

  1. This step verifies that the malfunction is present.

  2. If DTC P0404 will only set during certain conditions, the malfunction may be intermittent. Refer to Diagnostic Aids. If an intermittent wiring condition is not present, test for a faulty connection at the PCM or the EGR valve. If the connections are OK and if DTC P0404 continues to set, replace the EGR valve.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Important

If any of the following DTCs are set, diagnose the other DTC first:

  1. Install a scan tool.
  2. Turn ON the ignition.
  3. Use a scan tool in order to command the EGR valve from 0 percent to 100 percent.

Does the EGR position sensor remain within 15 percent of the Desired EGR Position at all commanded positions?

--

Go to Step 3

Go to Step 4

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, or within the parameters observed in the Freeze Frame/Failure Records .

Does the DTC fail this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4
  1. Turn OFF the ignition.
  2. Disconnect the EGR valve.
  3. Turn ON the ignition, with the engine OFF.
  4. Use a scan tool in order to observe the EGR position sensor parameter.

Does the scan tool indicate that the EGR Position Sensor is at the specified value?

0%

Go to Step 5

Go to Step 8

5

Measure the voltage from the 5-volt reference circuit of the EGR position sensor to the ground circuit of the EGR position sensor.

Does the DMM display voltage near the specified value?

5 V

Go to Step 6

Go to Step 7

6

Important

If the fuse blows, locate and repair a short to ground in the signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Connect a fused jumper between the 5-volt reference circuit of the EGR position sensor and the EGR pintle position signal circuit of the EGR position sensor.

Does the scan tool indicate that the EGR Position Sensor is near the specified value?

100%

Go to Step 12

Go to Step 10

7

Measure the voltage from the 5-volt reference circuit of the EGR position sensor to a good ground.

Does the DMM display voltage near the specified value?

5 V

Go to Step 9

Go to Step 11

8

Test the EGR pintle position signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

9

Test the EGR position sensor ground circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

10

Test the signal circuit for high resistance or a high resistance short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

11

Test the 5-volt reference circuit of the EGR position sensor for an open, for a short to ground, or for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

12

Inspect for poor connections at the harness connector of the EGR valve. Refer to Testing for Intermittent and Poor Connections and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

13

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent and Poor Connections and Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 15

14

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

Did you complete the replacement?

--

Go to Step 16

--

15

Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .

Did you complete the replacement?

--

Go to Step 16

--

16
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run, and pass?

--

Go to Step 17

Go to Step 2

17

Use a scan tool, in order to observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK