For 1990-2009 cars
Engine Controls Components
Power, Ground, MAF, EVAP, and EGR
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The powertrain control module (PCM) monitors the EGR valve pintle position input in order to ensure that the valve responds properly to the commands from the PCM. The Linear EGR valve is controlled by using an ignition positive driver and ground circuit within the PCM. The driver has the ability to detect an electrical malfunction in the ignition positive or ground circuit. If an electrical malfunction occurs, the driver signals the PCM to set DTC P0403.

### Conditions for Running the DTC

• | The engine is cranking or running.

• | The system voltage between 9.0-18.0 volts.

### Conditions for Setting the DTC

• | The PCM detects an electrical malfunction in the control circuit for the EGR valve.

• | The condition is present for more than 20 seconds.

### Action Taken When the DTC Sets

• | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive 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/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:

• | An open, a short to ground, and a short to voltage on the EGR Control circuit

• | An open on the EGR control ground circuit

• | If P0403 is determined to be intermittent, reviewing the Freeze Frame Failure Records may be helpful in determining the mileage since this code was last set.

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:

1. Listen for a click when the solenoid operates. Command the EGR between 0 percent to 10 percent. Repeat the commands as necessary.

2. This step verifies that the PCM is providing voltage to the solenoid.

3. This step tests for an open in the ground circuit to the solenoid.

4. This step tests if voltage is constantly being applied to the solenoid.

5. The PCM utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the On Board (OBD) Diagnostic System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Turn ON the ignition, with the engine OFF.
2. With a scan tool, command the EGR from 0-10 percent.

Does the solenoid turn ON and OFF with each command?

--

Go to Diagnostic Aids

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Disconnect the EGR.
3. Turn ON the ignition, with the engine OFF.
4. Probe the control circuit of the solenoid using a test lamp connected to a good ground.
5. With a scan tool, command the EGR between 0-10 percent.

Does the test lamp turn ON and OFF with each command?

--

Go to Step 4

Go to Step 5

4 |

1. Connect a test lamp between the control circuit of the solenoid and the ground circuit of the solenoid.
2. With a scan tool, command the EGR between 0-10 percent.

Does the test lamp turn ON and OFF with each command?

--

Go to Step 8

Go to Step 10

5 | Does the test lamp remain illuminated with each command? | -- | Go to Step 7 | Go to Step 6
6 | Test the control circuit of the solenoid for a short to ground or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9
7 | Test the control circuit of the solenoid for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9
8 | Inspect for faulty connections at the EGR. 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 13 | Go to Step 11
9 | Inspect for faulty connections at the PCM. 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 13 | Go to Step 12
10 | Test the ground circuit of the solenoid and connections at the PCM. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to step 12
11 | Replace the EGR. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | -- | Go to Step 13 | --
12 | Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Step 13 | --
13 |

1. Use the scan tool in order to record Fail Records and clear the DTCs.
2. Operate the vehicle within the Fail Records conditions.

Does the DTC reset?

--

Go to Step 2

System OK