Circuit Description
The exhaust gas recirculation (EGR) valve is controlled by the engine control module (ECM) through the EGR motor high control and the EGR motor low control circuits. The ECM supplies voltage that is near ignition voltage to the high and low control circuits at all times. The ECM will pulse width modulation (PWM) the low control circuit to ground when EGR is desired. The lower the pulse width, the more the valve will open. The ECM will PWM the high control circuit to ground when the EGR valve is desired closed. If the ECM detects an electrical malfunction on the control circuits, DTC P0403 will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0403 Exhaust Gas Recirculation (EGR) Solenoid Control Circuit
Conditions for Running the DTC
| • | The engine is running for more than 0.5 seconds. |
| • | The ignition voltage is between 11-18 volts. |
| • | The intake air temperature (IAT) is between 0-150.75°C (32-303.35°F). |
| • | The engine coolant temperature (ECT) is between 57-99.75°C (134.6-211.6°F). |
| • | The barometric pressure (BARO) is more than 72 kPa. |
| • | The EGR valve is commanded open. |
| • | DTC P0403 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
| • | The ECM detects an electrical malfunction on an EGR motor control circuit. |
| • | The above condition is present for more than 10 seconds. |
Action Taken When the DTC Sets - California
| • | 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. |
Action Taken When the DTC Sets - Federal
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The MIL will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center (DIC), if equipped, may display a message. |
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 Control Module Connector End Views and Engine Controls Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Did the DTC fail this ignition cycle? | Go to Step 3 | Go to Intermittent Conditions |
3 |
Did DTC P0403 fail this ignition? | Go to Step 4 | Go to Step 6 |
4 |
Important: The low control circuit of the EGR valve normally has near ignition voltage present. Test the low control circuit for a short to all other voltage circuits from the engine control module (ECM). Test the low control circuit of the EGR valve 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 10 | Go to Step 5 |
5 | Test the EGR motor high control circuit and low control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 7 |
6 | Test for shorted terminals and poor connections 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 10 | Go to Step 8 |
7 | Test for shorted terminals and poor connections at the 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 10 | Go to Step 9 |
8 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | Go to Step 10 | -- |
9 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | -- |
10 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 11 |
11 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
