• | 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, P0698, P2564 | P0102, P046C, P0401 | P0405 | P0106, 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 | P0401, P046C | P0403 | P0403, P2510 | -- |
EGR MTR Low Control | P0403, P046C | P0401, P046C | P0403 | P0403 | -- |
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 engine control module (ECM) uses the exhaust gas recirculation (EGR) position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference circuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position , is sent from the sensor to the ECM through the EGR position sensor signal circuit. The ECM compares the actual EGR position with the desired EGR position when the EGR valve is commanded open or closed.
The EGR valve is controlled by the 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.
• | The engine is running. |
• | The EGR is not actively being controlled. |
• | DTC P0403 runs continuously. |
OR
• | The engine is running. |
• | The EGR valve is actively being controlled. |
• | The ECT is greater than 60°C (140°F). |
• | DTC P0403 runs continuously. |
• | DTCs P0401, P0402, P0403, P0642, or P0643 are not set. |
• | The ECT sensor is greater than 60°C (140°F). |
• | DTC P046C runs continuously when the above conditions have been met. |
• | The ECM detects an electrical malfunction on an EGR motor control circuit. |
• | The above condition is present for more than 4 seconds. |
• | The difference between the actual EGR position and the desired EGR position is more than 3 percent. |
• | The above condition is present for more than 10 seconds. |
• | DTCs P0403 and P046C are Type B DTCs. |
• | Diesel particulate filter (DPF) regeneration is inhibited. |
DTCs P0403 and P046C are Type B DTCs.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
EN-48565 EGR Test Harness
Important:
• You must perform the Circuit/System Verification before proceeding with Circuit/System Testing. • Always replace the EGR valve gaskets when removal or replacement of the component is necessary.
⇒ | 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 and EGR gaskets. |
⇒ | If DTC P0403 was set replace the EGR valve motor. |
⇒ | If DTC P046C was set replace the EGR valve assembly and gaskets. |
• | Control Module References for ECM replacement, setup, and programming |