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Intermittent Engine Control Error warning


Posti

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My 1989 Reatta has started giving me an intermittent 'Engine Control Fault' warning combined with the Service Engine Soon'  - it dings and shows the warning screen on the CRT, then dings and goes out.  An engine diagnostic pass shows nothing wrong, and then it does it again.  There seems to be no pattern, and the car shows no signs of trouble.  It runs smooth with no hiccup, the warning pops up sometimes at highway speed, and sometimes while idling, and then sometimes doesn't show up at all for a long time.  My suspicion is that the O2 sensor is dirty or going bad.  Has anyone else run into this issue?  Suggestions?

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That sounds like it might be the oil pressure sender going bad. That is a common failure mode for it. The reason no code is set is because the warning must be displayed on the screen for a few seconds to set the code. If you will closely watch your oil pressure gauge on the CRT you will probably see the oil pressure spike for a second and then go back to normal and see the warning at the same time. The cure is to replace the oil pressure sender if that is you problem.

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Thanks! Not something I would have ever thought of! And an easy fix to try. I'll post with the results.

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Another culprit I suspect is the O2 sensor. I filled the car with high test and added a can of Seafoam cleaner. May or may not have made a difference, but i drove the Reatta to my parents' today (about 45 miles total) and never had the error come up. The oil pressure switch is due in tomorrow - I'll replace it anyway just to be safe.

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It will be interesting to see if the O2 sensor is/was the culprit. I'm still betting it is the oil sender because it is just so common of a problem.

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  • 2 weeks later...

I put the oil pressure sending unit in with no change in the intermittent engine code warning issue, though the car failed to start that night (unrelated, I am sure). So yesterday, I picked up a new O2 sensor ($19 from O'Reilly's) and installed that. Shockingly, I not only found the required special socket in my toolbox after some 15 years since the last use, but also got the job done in the specified ten minutes. The old one came out easily, and the new one threaded in by hand. No engine code warning on startup, but in truth I have not been able to run it long enough to test things out. It's been raining since and I had to use my truck for some work over at my parents'. Since the code warning was also intermittent, I'll need to run it a while to see if the O2 sensor did the trick.

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Even if the O2 sensor didn't fix the problem you didn't waste your money. I consider them a maintenance item that needs to be replaced around 50,000 miles. A dirty O2 sensor can effect you gas mileage even if there is no signs of a problem. I hope the O2 sensor fixes the problem. I really thought the oil pressure sender would. :S

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Still having the engine trouble code come up - intermittent, and seems to happen at low RPM/idle rather than cruising above 25.    So far I have replaced the oil pressure sending unit and the O2 sensor, and upgraded the ignition system to the Delco three-pack from a 1995 Buick 3800.  The Service Engine Soon light sometimes comes on with it, sometimes not.  There is no hesitation or other indication from the engine of trouble. However, while checking the diagnostic screen, I touched the cruise control 'OK' button and turned it off, and then the engine control issue came up again and the cruise control icon went back to OK.  Possibly a vacuum leak in the hoses?

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Still having the engine trouble code come up - intermittent, and seems to happen at low RPM/idle rather than cruising above 25. ...

 

What is the trouble code? Are you checking for codes using this procedure?

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Ah! No, I was just using the standard diagnostic - I'll use this. Everything I have done so far is good maintenance anyway. I drove the Reatta in to work today - it had the Engine Control Fault message pop up a lot until I got to the Interstate (.5 miles), and then it stopped completely (20 miles). Ran perfect, though. Thanks for the error code instructions.

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I ran the diagnostic and came up with EO41 and EO26 codes, both related to the camshaft sensor. I think it may be a dirty/corroded connector giving intermittent readings rather than a bad or broken sensor. The codes show up as History rather than current, but reappear as history items after I clear codes and run the car until the error shows up again. And the car sometimes goes a long time with no codes showing.

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It could be a bad connection causing it to be intermittent but most code E041 can be caused by a bad cam sensor magnet in the camshaft sprocket. There is a relatively easy fix if that is the problem. Thanks to Padgett for that.

 

The code E026 is probably caused by a different problem. A code E026 is sort of a "catch all" code that can be caused by several different things. It can be one of the hardest codes to figure out. Woody (89 Maui on this forum) wrote a good tutorial on how to trouble shoot the E026 code by a process of elimination.

Code E026 Troubleshooting

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I drove the car in to work again today and it started easily (35 degrees F) and ran perfectly for the 20+ miles. The code did not appear until I was close to office, running at 60 on the Interstate. So far the car has run perfectly. The sensor and magnet are both cheap, however. I will get them and wait for a nice weekend day to swap things out. One change - the Service Engine Soon light stopped coming on with the error code and it does not stay on a short time after I turn the car off. The light does come on at startup, though.

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The SES light should always come on when you turn the key on before the engine is started and then go out after the engine is running.

 

You should clear all the codes then drive the car until you see the error message displayed. Then go back into diagnostics and see if you have a code E041, E026 or both codes stored. If the cam sensor/magnet is the only problem you have only the code E041 will be stored in diagnostics.

 

Clearing codes in diagnostics is easy. After all codes are displayed, the screen will start asking questions. Keep pressing the NO button until it asks "ECM Clear Codes". Then press the YES button. All codes will be cleared. Don't worry, you can't damage anything in diagnostics.  You can also reset the codes by disconnecting the battery cable for a couple of minutes and then connecting it.

 

The procedure for clearing codes is explained on page 7 of the Onboard Diagnostics Instructions Booklet. You should really take the time to get to know that booklet. It is your best friend when troubleshooting your Reatta.

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  • 3 weeks later...

It has been five days and about 350 miles of driving since I replaced the plugs and wires on my Reatta - so far I have not had any trouble codes. I don't know if a damaged plug wire could cause the 041 code, or if I somehow fixed a bad connection while I was installing the plugs and wires. Or could be some temporary respite. I'll be happy whatever the cause until the code pops up again.

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The good thing about a code E041 is that it may annoy you but it won't leave you stranded. The engine should still run although maybe not hardly as good.

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Alas, the error code popped up twice early on during the drive to work this morning. I can detect no difference in the way the car runs - there is no hesitation or change in performance - I just get the warning tone and the error code appears on the screen, then goes away. I have the camshaft position sensor and interrupter in the trunk ready to install. If I get some good weather this weekend I'll probably swap them out.

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I would change the sensor first if you already have it. It's easy to change. While you're at is check and and clean all the connections.

 

Then drive it a while and see if the code E041 comes back. If it does then change the magnet using the Padgett method so you don't have to pull the timing cover.

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