CEL code P0400 on 98ES with 5 spd swap
98ES with 5 spd swap. CEL just came on. I pulled the trouble code and got P0400 ERG Flow Malfunction. Cleared the code and it was back next time I drove the car. I've read all the TGC threads that popped up after searching "P0400" but have a few questions to sort out what to do next.
1. I’ve read p0400 is a generic code for ERG problem. The MIts specific code is either 0401, EGR insufficient flow, P0402 (excessive flow) or 0403, EGR solenoid malfunction. Anyway to determine if it is really a 0401, 0402 or 0403 code without having to buy a Mits specific code reader? Anyone know if the code reader Autozone uses will provide more information beyond P0400?
2. Some say to change out the gas cap others say a bad gas cap will cause a different code and has nothing to do with P0400. Thoughts?
3. One thread stated the likely cause for P0400 is the EGR solenoid valve, the vacuum hoses going to it or the differential pressure sensor (this may not be applicable to 7g). How do I check this out?
4. What do you use and how do you clean the ERG valve? I ask because another thread stated P0401 is insufficient flow and P0402 is excessive flow. Insufficient flow could mean either a partially blocked EGR tube, blocked EGR pathway in the intake, sticking EGR valve (stuck closed), or a malfunctioning EGR solenoid. Excessive flow could mean that your EGR valve is stuck open and needs to be cleaned. Might also mean the solenoid is stuck open. Start with inspecting and cleaning the EGR valve