Knock Sensor Inoperative - DTC 22 or 28
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It has been determined that a small percentage of the applicable vehicles may experience improper operation of the Knock Sensor assembly due to breakage of an internal lead wire. Should this occur, the driver will experience illumination of the Malfunction Indicator Light (MIL or "Check Engine" light) and a slight reduction in engine power due to retarded ignition timing ("fail safe" mode.) Should the above condition occur, the technician will find diagnostic trouble codes as follows:
Legacy 2.2L 1990-1994 MY
Legacy/Impreza 2.2L 1995 MY
SVX 3.3L 1992-1995 MY
If you encounter a complaint with the codes listed above, it will be necessary to replace the affected Knock Sensor with a new one - part number 22060AA031. The color of the connector on the replacement knock sensor has changed from gray to white for positive identification. When servicing SVX models, replace both knock sensors even if the second diagnostic trouble code has not illuminated. After the repair, clear the diagnostic trouble code(s). In the unlikely event that the Malfunction Indicator Light remains on or the above specified diagnostic trouble code(s) reappear, refer to the applicable service manual for proper diagnostics. Installation of the Knock Sensor can be claimed under the terms of the Subaru Emission Control Systems warranty.
Applicability: 1990-1995 Legacy/1995 Impreza 2.2L
Note: Refer to the applicable service manual for 1990-1995 Legacy and 1995 Impreza 2.2L knock sensor replacement procedure.
Applicability: 1992-1995 SVX 3.3L
Note: Refer to revised 1992-1995 SVX 3.3L knock sensor replacement information on the reverse side.
Revised SVX Service Manual Removal And Replacement Procedures For Knock Sensors Number 1 (RH) and Number 2 (LH). This information supersedes the Removal And Replacement Procedures listed in the SVX Service Manuals.
Left Sensor Replacement
Note: When removing the knock sensor, the wire connector is tight but will pass between the coolant crossover manifold and the engine block.
Right Sensor Replacement
Note: Torque the knock sensor mounting bolt(s) for all applicable models to 17.4 +/- 2.1 ft-lb.
Note: Refer to the applicable service manual for proper knock sensor mounting bolt torque.