• | 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 provide an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Ignition 1 Voltage | P0405 | P0405 | -- | P0404, P1404 |
Solenoid Control | P0402, P0404 | P0404 | P0404 | P0404, P1404 |
5-Volt Reference | P0405 | P0404, P0405 | -- | -- |
EGR Position Sensor Signal | P0405 | P0405 | P0406 | P0404, P1404 |
Low Reference | -- | P0406 | -- | -- |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: 0-3% | |||
Ignition 1 Voltage | -- | -- | -- |
Solenoid Control | 100% | -- | -- |
5-Volt Reference | 0% | 0% | 100%¹ |
EGR Position Sensor Signal | 0% | 0% | 100%¹ |
Low Reference | -- | 0% | -- |
¹ Internal ECM damage may occur if the circuit is shorted to B+. |
Voltage is provided to the exhaust gas recirculation (EGR) valve by the ignition 1 voltage circuit through a fuse. Ground is provided to the EGR valve on the control circuit by a low side driver within the engine control module (ECM). The ECM monitors the voltage on the control circuit of the EGR valve to determine if a failure is present.
The ECM monitors the position of the EGR valve through the EGR valve position sensor. The EGR valve position sensor sends a feedback voltage on the signal circuit to the ECM. The EGR position sensor voltage varies depending on the position of the EGR valve.
The EGR valve utilizes the following circuits:
• | An ignition 1 voltage circuit |
• | A control circuit |
• | A 5-volt reference circuit |
• | A signal circuit |
• | A low reference circuit |
• | DTCs P0112, P0113, P0405, P0406, and P0502 are not set. |
• | The engine is running |
• | The intake air temperature (IAT) is greater than 3°C (37°F). |
• | The DTC run continuously when the above conditions are met. |
• | The engine is running. |
• | The ignition voltage is between 11.7-16 volts. |
• | The DTC runs continuously when the above conditions are met. |
The ECM detects a difference between the actual EGR position and the commanded EGR position of more than 15 percent.
The ECM detects that the EGR position sensor percentage is less than 2 percent.
The ECM detects that the EGR position sensor percentage is greater than 98 percent.
The ECM detects the difference between the actual EGR position and the learned EGR position is greater than 10 percent.
DTC P0404, P0405, P0406, and P042E are Type B DTCs.
Exhaust Gas Recirculation (EGR) System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Important: The test lamp is used to load the circuit and may not illuminate.
⇒ | If less than B+, repair the ignition 1 voltage circuit of the EGR valve for a short to ground or an open/high resistance. |
⇒ | If test lamp illuminates, test the control circuit of the EGR valve for a short to ground. If the circuit/connections test normal, replace the ECM. |
⇒ | If greater than 0.5 volt, test the control circuit of the EGR valve for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM. |
⇒ | If greater than 1 percent, test the signal circuit of the EGR position sensor for a short to voltage. If the circuit/connections test normal, replace the ECM. |
Important: The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.
⇒ | If less than 4.8 volts, test the 5-volt reference circuit of the EGR position sensor for a short to ground or open/high resistance. If the circuit/connections test normal, replace the ECM. |
⇒ | If greater than 5.2 volts, test the 5-volt reference circuit of the EGR position sensor for a short to voltage. If the circuit/connections test normal, replace the ECM. |
⇒ | If greater than 0.2 volt, test the low reference circuit of the EGR position sensor for a short to voltage. If the circuit/connections test normal, replace the ECM. |
⇒ | If greater than 5 ohms, test the low reference circuit of the EGR position sensor for an open/high resistance. If the circuit/connections test normal, replace the ECM. |
⇒ | If less than 99 percent, test the signal circuit of the EGR position sensor for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM. |
⇒ | If the resistance is out of the specified range, replace the EGR valve. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |