Circuit Description
The PCM controls the movement of the valve using the EGR control circuit. The control circuit consists of a high side driver and feed circuit, the EGR solenoid, and a ground circuit. The PCM turns ON the high side driver to supply ignition voltage to the EGR control circuit. The PCM monitors the high side driver for improper voltage levels in the EGR control circuit. If the PCM detects an improper voltage in the EGR control circuit, DTC P0403 will set.
Conditions for Running the DTC
| • | The engine is running. |
| • | System voltage is between 8-16 volts. |
Conditions for Setting the DTC
The PCM detects an improper voltage in the EGR ignition feed, EGR solenoid, or EGR ground circuit for at least 10 seconds.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails. |
| • | The PCM stores the conditions present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool Clear DTC Information function. |
Diagnostic Aids
Check the harnesses and connectors for the following conditions:
| • | Poor connections at the PCM and the EGR valve. |
| • | Backed out terminals |
| • | Improperly mated connectors |
| • | Broken locks |
| • | Improperly formed or damaged terminals |
| • | Poor terminal to wire connections |
| • | A damaged harness. |
Refer to Wiring Repairs in Wiring Systems.
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may assist in diagnosing the condition. The information may help in determining how often the condition occurs that caused the DTC to set.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if the EGR valve can be commanded open.
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Excessive resistance in the EGR control circuit or the EGR ground circuit will result in the EGR not responding correctly to the commanded EGR position.
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This step tests the EGR Valve control circuit.
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This step tests the EGR Valve ground circuit.
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Excessive resistance in the control circuit or the ground circuit will cause this DTC to set. With the EGR commanded to 100 percent the test lamp should light with full intensity. Connect the test lamp across the battery terminals and compare the test lamp intensity to the EGR control circuit intensity.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the engine run rough or stall? | -- | |||
Is the Actual EGR Position within the specified range? | 48-52% | Go to Diagnostic Aids | ||
Is the resistance within the specified range? | 0-2 ohms | |||
Test the continuity of the EGR valve ground circuit with the DMM. Is the resistance within the specified range? | 0-2 ohms | |||
Is the test lamp illuminated? | 100% | |||
7 | Probe the EGR ground circuit with a test lamp connected to B+. Refer to Probing Electrical Connectors in Wiring Systems. Is the test lamp illuminated? | -- | ||
8 |
Does the DMM display continuity? | -- | ||
9 | Test the continuity of the EGR valve control circuit with the DMM connected to ground. Refer to Testing for Continuity in Wiring Systems. Does the DMM display continuity? | -- | ||
10 | Test for continuity from the EGR control circuit to all other circuits in the PCM harness connector. Refer to Testing for Continuity in Wiring Systems. Does the DMM display continuity to any other circuit in the PCM harness connector? | -- | ||
11 |
Does the DMM display continuity? | -- | ||
12 | Repair the EGR valve control circuit for an open, short to ground or short to another circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
13 | Repair the open in the EGR valve ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
14 | Repair the high resistance in the EGR valve control circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
15 | Repair the high resistance in the EGR valve ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
16 | Inspect for poor connections at the EGR valve electrical connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | -- | ||
17 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Is the replacement complete? | -- | -- | |
18 | Inspect for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did find and correct the condition? | -- | ||
19 |
Important:: Program the replacement PCM. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | |
20 |
Does the scan tool indicate that this test passed? | -- | ||
21 | Select the Capture Info option and the Review Info option with the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
