• | 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 | 1 | P0403 | -- | P0404 |
Solenoid Control | P0489 | P0403 | P0490 | P0404 |
5-Volt Reference | P0107, P0405 | P0405 | -- | -- |
EGR Position Sensor Signal | P0405 | P0405 | P0406 | P0404 |
Low Reference | -- | P0406 | -- | -- |
1. Engine cranks but does not run and the fuse for the ignition 1 circuit opens. |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: 0-4% | |||
Ignition 1 Voltage | -- | -- | -- |
Solenoid Control | 99% | -- | -- |
5-Volt Reference | 0% | 0% | 99%¹ |
EGR Position Sensor Signal | 0% | 0% | 99%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 |
• | The engine is running. |
• | The ignition voltage is between 10-16 volts. |
• | The engine fuel-cutoff is disabled - P0404 only. |
• | The DTCs run continuously once the above conditions are met. |
The ECM detects a difference between the actual EGR position and the commanded EGR position of more than 20 percent.
The ECM detects that the EGR position sensor voltage is less than 1 volt.
The ECM detects that the EGR position sensor voltage is greater than 4.7 volts.
DTC P0404, P0405, and P0406 are Type B DTCs.
DTC P0404, P0405, and P0406 are Type B DTCs.
Exhaust Gas Recirculation (EGR) System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests 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 the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |