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P0420 Diagnostic Trouble Code Discussion for May 2012

Catalyst Efficiency Below Normal (Bank 1)

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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2002 Subaru Impreza WRX 2.0L MIL Lamp on VIN: JF1GD29692
P0420: Catalyst Efficiency Below Normal (Bank 1). Originally came November 2011 with p0420. customer got dealer to warranty front cat. Vehicle has front and rear cats between the a/f sensor & rear O2 sensor.vehicle came back in april with a a/f ratio sensor code. Sensor tested bad & we replaced it &am...
May 18, 2012
2002 Saturn L200 2.2L Hesitation, 1st gear sluggish VIN: 1G8JT54F52
P0420: Catalyst System Low Efficiency (Bank 1). ... into the shop for a no-start issue and we found that the fuel pump needed to be replaced so the fuel pump was installed and the vehicle started up just fine; however, after initially road testing the vehicle the technician noted that the vehicle felt slugg...
May 31, 2012