Engine - Rough Idle/Rough RPM Increase on Acceleration

NUMBER: 02-97-05
DATE: 10/06/05

APPLICABILITY:
04MY Forester 2.5L Turbo;
04MY Baja 2.5L Turbo;
04MY Impreza STi 2.5L Turbo

SUBJECT:
Active Valve Control System (AVCS)
Union Screw Filter

INTRODUCTION

If you encounter a customer complaint of a rough idle and/or rpm does not increase smoothly there is the possibility that the union screw filter of the Active Valve Control System (AVCS) could be damaged affecting the oil control valve~ Always refer to the applicable Subaru Service Manual when performing diagnostics for a rough idle~

PRODUCTION LINE CHANGE





A countermeasure was made eliminating the filter from the union screw in April of 2005 starting with the VINs shown.

PARTS INFORMATION

The new part number for the union screw (without filter) is 15194AA270.

REPAIR PROCEDURE/INFORMATION

1) Connect the Subaru Select Monitor to the data link connector.

2) Warm up the engine until the engine oil temperature reaches 80°C / 176°F; this can be verified using the Subaru Select Monitor.

3) Turn the ignition switch to the off position.

4) Restart the engine and keep the engine speed within 2000~3000 rpm for 3 seconds.

5) Let the engine idle for 5 seconds.

6) Check the advance angle of AVCS using the Subaru Select Monitor. If the reading is 50 or more continue with the following steps. If the reading is less than 5, follow the troubleshooting diagnostics in the applicable Subaru Service Manual.





7) Remove the union screw C (oil control valve side, see figure 1 and 2).

NOTE:
Do not remove the union screw from the cylinder head side (A).

8) Inspect the union screw filter. If damaged remove the oil control valve and clean any filter debris. If debris cannot be cleaned, replace the valve.

9) Remove the filter from the union screw and discard.

10) Reinstall the original union screw without the filter.

11) Replace the engine oil and filter.





WARRANTY / CLAIM INFORMATION

For vehicle within the Basic New Car Limited Warranty period, this repair can be claimed using:

Note:
The labor time listed includes engine oil and filter change.





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