I had my check engine light come on and a guy at a discount auto said it was insufficient flow on EGR. I‘m not a mechanic or know much about cars. Can anyone help me?
Vehicle: 1996 - 2001 Toyota Rav4 2.0L Symptom: The check engine light is on with a stored code P0401. System: Emissions/PCM/Fuel Codes: P0401 Problem: The Exhaust Gas Recirculation (EGR) Vacuum Switching Valve (VSV) is bleeding off the vacuum for the EGR valve causing low EGR flow. Test Fix: Apply vacuum to the EGR valve at idle to see if the engine will stall. If it does not stall the engine, this Repair-Trac does not apply. Check the back pressure transducer by blocking the ports that are side by side with a pair of pliers. With the vehicle at idle, blow into the port on the back pressure transducer that normally goes to the EGR valve. Raise the engine RPM's to 3000. It should be harder to blow into the port at 3000 RPM's than it was at idle. Testing vacuum to the EGR valve has had mixed results that have led to a lot of unnecessary testing and replacement of parts. Due to the high failure rate of the EGR VSV, it is best to start by replacing it first and then doing more in depth testing if the code comes back. Known good vehicles have been tested with a vacuum gauge tee'd in to the hose at the EGR valve and readings of 5-7 inches of vacuum were recorded while driving under normal loads.
the computer directs a specific amount of exhaust gas back through the engine to reduce emissions. (Exhaust Gas Recirculation). Insufficant flow means that what the computer expects to see is not actually happening. The EGR port maybe clogged or the valve is stuck closed or an electrical problem has occured.Repair cost about $400.
