obd1 dtc 412 and dtc538 codes

rawmacias

Registered User
Can anybody give me direction on how to remedy these codes ? My SC HAS 80 grand miles and engine bay has not been messed with besides replacing a water hose/pipe that connects to the temp sensor riser. Antifreeze did squirt out over the passenger side area. The check engine light does not blink off and on, but does come on for a short while (a few minutes ) then goes off . Sometimes I can drive for miles without it coming on. I did put another elect fan on the front side.
 
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Can anybody give me direction on how to remedy these codes ? My SC HAS 80 grand miles and engine bay has not been messed with. I did put another elect fan on the front side.

  • 412 R Unable to control RPM during high RPM self-test
    [*]538 R Insufficient change in RPM

....did you bury your foot during the goose test?

What's the issue that prompted you to check codes?
 
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I added more info on my thread. Yes, I did what the obd1 reader told me to do. I turned the steering wheel a half turn for 4 sec. then pressed the brake pedal and then pushed the throttle to the floor and let go. I was getting a check engine light once in a while. Not blinking off and on , but just once in a while. A coolant leak was found while I was setting up the reader. It leaked coolant on the passenger side just above the back and center spark plugs. I repaired the hose/pipe combo. But still getting a check engine light and the codes. And thanks for your reply !
 
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What is your idle speed?

When you did the cooling system repair, did you make sure to bleed all the air out of the system? What procedure did you follow?
 
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I probably didn't bleed out the air correctly but this is what I did. I raised the front of the car quit a bit, then opened the cap and then squeezed the top hose to get the air out as much as i could. I was topping off the coolant as i did this til i could not get any more air out and did not here any bubbling when i squeezed the hose. Would air cause these codes ?
 
Did you use the air bleed screw on the stem on the thermostat housing at all when filling? I would use that and leave the cap in place. Then drive it around for couple days before testing/troubleshooting. Might do that, then clear codes and then see what happens after a day or so.

Air can get trapped at the ECT sensor and cause issues before it finally bleeds out.

What is your idle speed?
 
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I did not write down the idle speed. I will use the bleed to see if i can get more air out then drive it around for awhile , at least til tomorrow. Then i will post what happened. I did find a website that directed me to replace the tps sensor, but i want to make sure what i am doing is the best . I don't want to start replacing parts until the check engine light doesn't come on anymore. Also, I thought the check engine light was only related to smog issues like air /O2 , maf and such. Hey , thanks for your help for today. And I will post again tomorrow.
 
Don't drive the car at all until you get the air bled out of the top fitting. I popped a head gasket on a 3.8 N/A from an air bubble like that.
 
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Well, I used the bleed . Removed the threaded top. Filled the radiator til the coolant was at the top of the tube. Put the threaded top back on the bleed. Made sure the radiator was topped off and put cap back on. Filled the reservoir to cold level. Checked connectors and hoses again. Took the car for a ride til the temp gauge needle was in about the mid point, then drove some more to be sure it did not move. The check engine light still comes on for a while then goes off for a while when i was driving it. Nothing changed.
 
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I have both Ford manuals for the car and tried to find the bleed procedure . I found illustrations of the bleed tube/cap , but no procedure on how to bleed. The only info I found was when the radiator or coolant was drained. It just said to fill the radiator and add to the reservoir . It did mention that any air would dissipate through the overflow tube and into the reservoir. These are the factory manuals which i have two sets.
 
The (simple) procedure should be on the cap/skirt on the bleed-bolt. Be sure the center hole in the bolt isn't blocked.

The detailed procedure from cold engine when the system has been opened, is to loosen the bolt, fill the radiator until coolant flows out around the bolt (pump the top hose to be sure no large air pockets are present), install the radiator cap, tighten the bolt, be sure the overflow tube to the coolant expansion tank isn't blocked, add coolant to the HOT line and drive. If the system is operating properly, the next time the engine cools down overnite, the level should be close to COLD. Be sure to use s straight !6# cap, not one that works over a range, say 13 ~ 16. Drive it around for a couple days and pay attention to the level in the tank. Only add if below COLD overnite. Resist the urge to remove the cap and peek into the radiator.

After a few days and once you're confident the cooling system has stabilized, if you still see an intermittent light you can move to other checks, etc.

What you can do now is to check the connector at the ECT to be sure it's clean and fully seated - do the same for the ground connection for the harness to the header panel in front of the battery.
 
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ect connector and all other connectors were checked and seemed to be fine. So now , after driving around this morning , I will not drive it the rest of the day to allow it possibly loose any more air and refill from the reservoir . I will drive it tomorrow and post again tomorrow. And thanks for following up on my posts.
 
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