qwikrex Posted February 28, 2009 Share Posted February 28, 2009 I've got a 1992 ES300 which has the engine trouble code 71, causing the check engine light to be on. I have to smog this thing in less than two weeks, and I'm trying to troubleshoot. I've checked the EGR valve, and it moves freely when vacuum is applied. I cleaned it to be thorough but I'm certain it's not sticking. After cleaning it and reinstalling, I did a drive test, and the check engine light came back on. I'm going to run the vacuum tests from the factory service manual, but I wanted to see if there were any other common EGR problems I might get some guidance on. Does the temperature sensor in the EGR valve fail often? Any guidance would be appreciated. When/if I get it figured out, I'll be sure to post back here. Quote Link to comment Share on other sites More sharing options...
qwikrex Posted February 28, 2009 Author Share Posted February 28, 2009 Okay.. Temp sensor checks out, TVV checks fine, and the EGR valve opens under vacuum and causes the engine to stumble suggesting the presence of exhaust gasses. Just came in to peek at the service manual and check if there were any updates there. Going to check for vacuum from the "source" for the EGR system, namely the throttle body. If that checks out, the only thing I can imagine is that the wiring between the EGR temp sensor and the ECM might be toast. Any ideas folks? Quote Link to comment Share on other sites More sharing options...
qwikrex Posted March 1, 2009 Author Share Posted March 1, 2009 Okay, the vacuum source from the throttle body checked out. Turned out I had the hoses crossed between the two temperature controlled valves. There is one for the IAC and one for the EGR system, and the hoses were swapped. Fixed that up, and took the car to be smogged. It passed perfectly... Then... On the way home, the check engine light popped back on!! This time it's two codes 25 & 26. Looks like a problem with a modulator valve between the two cylinder banks. Back to work, at least it passed smog! haha! Quote Link to comment Share on other sites More sharing options...
peter12345l Posted March 13, 2009 Share Posted March 13, 2009 Okay, the vacuum source from the throttle body checked out. Turned out I had the hoses crossed between the two temperature controlled valves. There is one for the IAC and one for the EGR system, and the hoses were swapped.Fixed that up, and took the car to be smogged. It passed perfectly... Then... On the way home, the check engine light popped back on!! This time it's two codes 25 & 26. Looks like a problem with a modulator valve between the two cylinder banks. Back to work, at least it passed smog! haha! hi. my car just got the engine light on. also 92 es 300. would you like to tell how to check to get the code? step by step please. if have picture there will be perfect for me. thanks Quote Link to comment Share on other sites More sharing options...
capnfred Posted March 13, 2009 Share Posted March 13, 2009 Go to the top of the forum where it says merry xmas, factory shop manual, follow the steps and get the manual, then follow the instructions, its all there, all you need is a paperclip bent into a u-shape, or a piece of wire, good luck, and keep us informed Capn Quote Link to comment Share on other sites More sharing options...
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