P0490

DTC P0490 EXHAUST GAS RECIRCULATION CONTROL CIRCUIT HIGH VOLTAGE

Component Location:

COMPONENT LOCATION

GENERAL DESCRIPTION
The Exhaust Gas Recirculation (EGR) system is designed to introduce exhaust gas into the combustion cycle. This lowers combustion temperatures and reduces the formation of oxides of nitrogen. The amount and timing of exhaust gas introduced into the combustion cycle varies by such factors as engine speed, engine vacuum, exhaust system back pressure, coolant temperature and throttle position.

DTC DESCRIPTION
If the output voltage is satisfied with threshold value, the PCM determines that a fault exists and a DTC is stored.

DTC Detecting Condition:

Schematic Diagram:

TERMINAL & CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals.
Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?

YES: Repair as necessary and go to "Verification of Vehicle Repair" procedure.

NO: Go to " Control Circuit Inspection " procedure.

CONTROL CIRCUIT INSPECTION
1. Check for short to battery in harness
1. Ignition "OFF"
2. Disconnect EGR Sol.Valve connector.




3. Measure resistance between terminals "1" and "2" of EGR Sol.Valve harness connector.
Specification: Infinite

4. Is the measured resistance within specifications?

YES: Go to" Component Inspection " procedure.

NO:
- Check for short to battery in harness between EGR Sol.Valve connector and PCM connector.
- Repair or replace as necessary and then, go to " Verification of Vehicle Repair" procedure.

COMPONENT INSPECTION
1. Check EGR Control Valve
1. Ignition "ON" & Engine "OFF"




2. Connect Scantool and perform Actuation Test for EGR control valve with scantool.
3. Is the EGR control valve working properly?

YES:
- Substitute with a known - good PCM and check for proper operation.
- If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.

NO:
- Substitute with a known - good EGR control valve and check for proper operation.
- If the problem is corrected, replace EGR control valve and go to "Verification of Vehicle Repair" procedure.

VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs.
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Monitor that all readiness tests have been verified as " Complete"
5. Are any DTCs present?

YES: Go to the applicable troubleshooting procedure.

NO: System is performing to specification at this time.