• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
EGR 5-Volt Reference Voltage | P0107, P0401, P0698, P2564 | P0102, P046C, P0401 | P0405 | P0106, P0401, P0699, P2227, P2565 | -- |
EGR Sensor Signal | P0405 | P0101, P0405 | P0405 | P0699, P0106, P2565, P0401 | -- |
EGR Low Reference | -- | P0401, P046C | P0406 | -- | -- |
EGR MTR High Control | P0403, P046C | P0401, P046C | P0401, P046C | P0403, P2510 | -- |
EGR MTR Low Control | P0401, P0403, P046C | P0401, P046C | P0401, P046C | P0401, P046C, P0403, P2510 | -- |
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
---|---|---|---|---|
Operating Conditions: Engine Running, ECT sensor is less than 60°C (140°F) | ||||
EGR 5-Volt Reference Voltage | 0.98 Volts | 0 Volts | 0 Volts | 1.29 Volts |
EGR Sensor Signal | 0.98 Volts | 0 Volts | 0 Volts | 4.98 Volts |
EGR Low Reference | 0.98 Volts | -- | 4.8 Volts | -- |
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.
• | The engine is running for more than 0.5 second. |
• | The EGR duty cycle is more than 10 percent. |
• | DTC P0403 runs continuously when the above conditions are met. |
• | The ECM detects an electrical malfunction on an EGR motor control circuit. |
• | The above condition is present for more than 30 seconds. |
• | 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. |
• | The control module turns OFF the 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. |
EN-48565 EGR Test Harness
Important: If you cannot duplicate the condition, 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.
⇒ | If DTC P046C is also set, diagnose DTC P046C first. |
Important: Perform the Circuit/System Verification before proceeding with Circuit/System Testing.
⇒ | If the lamp does not turn ON and OFF, test both motor control circuits for an open/high resistance, short to voltage, or short to ground. If the circuits test normal, replace the control module. |
⇒ | If the lamp turns ON and OFF, replace the EGR valve motor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |