pfeener Posted February 11, 2006 Report Share Posted February 11, 2006 98 S70 GLT with 186,000 miles. The check engine light has been on for a few years, but I knew the air pump was siezed (again) so I ignored it. I just got around to replacing the air pump and check valve (used a procedure I found on Matthew's Volvo site for converting a VW pump; real easy, works great; scored the pump on ebay for $45 including shipping; highly recommended route to go) After I replaced the pump, the ECU wouldn't turn on and run the pump when the engine was cold. (runs fine when I jump the relay). I pulled the codes and got a PO300, 301, 302, 304 and a PO130. The 300 series codes are all for cylinder misfires and the 130 code is a front O2 sensor circuit malfunction. In addition the Catalyst monitor, Evaporative System Monitor, Secondary Air System Monitor and Oxygen Sensor Monitor are blinking on the reader, meaning they have not run to completion. My assumption is that the ECU won't turn on the air pump until I get the other things fixed and the Secondary Air Monitor runs to completion. I'm also assuming the 300 codes are erroneous since I recently changed out the plugs, wires, cap and rotor with genuine Volvo parts. I'm thinking the front O2 sensor may be the root problem since it has about 145K miles on it. Am I thinking of this right or am I on a dusty road, headed for a cliff?When I clear the codes, the check engine light is back on everytime within 10 miles of driving. The 300 series codes are not always the same cylinders but the PO130 code is always consistant. Link to comment Share on other sites More sharing options...
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