P0490

P0490-EGR CONTROL CIRCUIT HIGH





For a complete wiring diagram refer to Diagrams/Electrical

- When Monitored:

With the ignition on and the EGR Solenoid command on.

- Set Condition:

The Engine Control Module (ECM) detects that the (K34) EGR Solenoid Control circuit is shorted to voltage for 2.0 seconds.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.


Diagnostic Test

1. DTC IS ACTIVE

Ignition on, engine not running.

With the scan tool, Clear DTCs in the Engine Control Module (ECM).

With the scan tool, actuate the EGR Solenoid.

Monitor the scan tool for at least two minutes.

Start the engine.

With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

- Go To 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Checking for an Intermittent DTC


2. (K34) EGR SOLENOID CONTROL CIRCUIT SHORTED TO VOLTAGE





Turn the ignition off.

Disconnect the EGR Solenoid harness connector.

Disconnect the Engine Control Module harness connector.

Remove the ASD Relay from the PDC.

Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay Connector.

Turn the ignition on.

Measure the voltage of the (K34) EGR Solenoid Control circuit in the EGR Solenoid harness connector.

Is there any voltage present?

Yes

- Repair the (K34) EGR Solenoid Control circuit for a short to voltage.
- Perform the ECM Verification Test Ver. 1. ECM Verification Test

No

- Go to 3


3. (K34) EGR SOLENOID CONTROL CIRCUIT SHORTED TO THE (A15) FUSED ASD RELAY OUTPUT CIRCUIT





Turn the ignition off.

Remove the jumper wire and install the ASD relay.

Measure the resistance between the (K34) EGR Solenoid Control circuit and the (A15) Fused ASD Relay Output circuit in the EGR Solenoid harness connector.

Is the resistance above 1000 ohms?

Yes

- Go to 4

No

- Repair the (K34) EGR Solenoid Control circuit for a short to the (A15) Fused ASD Relay Output circuit.
- Perform the ECM Verification Test Ver. 1. ECM Verification Test


4. (K34) EGR SOLENOID CONTROL CIRCUIT OPEN OR HIGH RESISTANCE





Measure the resistance of the (K34) EGR Solenoid Control circuit between the EGR Solenoid harness connector and the Engine Control Module (ECM) harness connector.

Is the resistance below 10.0 ohms?

Yes

- Go to 5

No

- Repair the (K34) EGR Solenoid Control circuit for an open circuit or high resistance.
- Perform the ECM Verification Test Ver. 1. ECM Verification Test


5. EGR VALVE

Connect the Engine Control Module (ECM) connector.

Replace the EGR Valve.

Turn the ignition on.

With the scan tool, Clear DTCs.

With the scan tool, actuate the EGR Solenoid.

Monitor the scan tool for at least two minutes.

With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

- Go to 6

No

- Test Complete.
- Perform the ECM Verification Test Ver. 1. ECM Verification Test


6. ENGINE CONTROL MODULE (ECM)

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the EGR Solenoid and the Engine Control Module (ECM).

Look for any chafed, pierced, pinched, or partially broken wires.

Look for broken, bent, pushed out or corroded terminals.

Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. ECM Verification Test

No

- Replace the Engine Control Module (ECM).
- Perform the ECM Verification Test Ver. 1. ECM Verification Test