Hey guys, im getting the cel 71, EGR, checked the hoses, they seem ok. Opened up the EGR vaccum modulator and cleaned filter, blew in the port and it checked good. Put a vacuum to check the valve, that checked good. I did a hard reset ( disconnected neg battery cable) went away for a week. then came back again, did another hard reset, cel went out but i know that i still have a problem. any other ideas?

 

Apply vacuum to the EGR valve with the engine idling, use a hand vacuum pump. The engine should run rough and almost stall. If it doesn't, then either the valve is bad or the ports are plugged up. If it does run rough or stall then the problem must be in the vacuum supply to the egr valve i.e egr solenoid, circuit or vacuum hose.

 

This is quite a useful post because I think that one of my friends mention that he is experiencing the same issue with the egr. I'm gonna share this to my friend, it might come in handy for him. Thanks for this tip.

 

How are you figuring you still have a problem?

you only need to disconnect the ECU for a few seconds to clear the code. if it's still there, it cam BACK.

IIRC these trucks don't have much in the way of diagnosis system. most codes are a result of short- or open circuits. the 93 FSM online doesn't list code 71 but my cressida's manual lists it with an EGR gas temp sensor...IE if the sensor doesn't read hot enough (IE exhaust passing by) it sets the code. Every one of my old toyotas has had the EGR passages so caked up in carbon i was digging it out for an hour, I wouldn't be surprised if that's your problem.