Got the above mentioned car in and everything worked fine as long as you took it easy on the throttle. If you nailed it or drove it normally it would go into limp home mode (the CEL is inoperative on the car). Hooked the trusty machine to it and got HFM ctl unit, 056 - ign. output stage 1 T1/1, cyl 5 misfire, 059 - ign. output stage 2 t1/2, cyl 4 misfire, 079 - knock sensor and finally 095 transmission overload protection switch. I studied up on the transmission fault code and found that this typically means the switch is open circuit which it was. Does anyone know if the sequence that the codes are presented show which came in first, second, third, etc...?

I'm thinking that if I swap it out and clear the codes then the first three will not come back.

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Jim

Were the codes in the DM or in the HFM?

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All of them were listed under HFM. There were some body faults listed but I did not really pay any attention to them.

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Jim

I see the trans overload switch Often in diag, more often then Not really. In some cases it will cause running issues (lurching/hitching, esp when cold) it's a 50/50 if it throws a CEL.

I'd suspect the misfire is what's throwing the CEL, I'd be a bit surprised if that was connected to the trans overload switch...

That said, they're not that bad to change.

Jonathan

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Jonathan Hodgman
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Changed out the switch and that code went away but continued to miss and stay in limp home mode. This time around the only codes left were:

059 Ign output stage 2 T1/2 cyl 4 misfire
079 Knock sensor

Cleared codes, replaced plugs/connectors and everything is back to normal. It looks like someone has probably removed the bulb for the check engine light. It never comes on. The plugs were the correct type but looked like they tried to get 100k out of them.

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Jim

I suspect the transmission is on it's way out. It got to where it would not go into high gear after having driven for about 20 miles. When it was brought in it ran so badly you could not really tell much about the transmission because of it being in limp home going on. The guy that brought it in said that he had just had a transmission fluid/filter change done by a transmission shop in Warner Robins. After seeing such poor performance I drained the transmission and dropped the pan/filter. I have attached a pic of the filter. It is badly plugged and had some substantial dirt/nasty on top of it. Could a severely plugged filter cause a car to not go into high gear? I would think it could because it would be similar to running it with the transmission fluid too low. I suspect this is the result of one of those transmissions that never got the fluid changed. I'll let ya'll know the results over the next day or so.

Oh yea, there are no engine runnability issues anymore.

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Jim

It looks like a clogged transmission filter was causing the transmission problem. Installed a new filter, got the fluid level set and everything seems to be doing fine. This was my first experience with a clogged transmission filter.

Car is well sorted now.

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Jim