More 99 Sonata trouble codes

1. I can't think of any way this would be related to the crank sensor.

1. There's nothing that indicates that these problems are related in any way. Since they're all unrelated, there's no way to predict from these failures how many future failures will occur or when they'll happen.

If you have the capability of reading the freeze frame data, check the coolant temperature in the freeze frame data. A very high temperature would indicate overheating. In this case, you should do a thorough check of the cooling system. A very low temperature (often -40) typically indicates a faulty sensor. A seemingly normal to a little low temperature often indicates a thermostat problem.

If you have no way to check freeze frame data, start with the cooling system audit. If okay, then your chances are good with replacing the sensor. If the thermostat isn't fairly new, I'd recommend replacing that as well. It doesn't cost much, is fairly easy to do, and it's better than having it fail later.

1. Sounds like the correct sensor. I believe it has three wires going to it-- two for the PCM and one for the gauge.

1. It'll depend on the construction of the socket. Many deep sockets only have the hex on the bottom 1" or so, leaving a circular portion toward the top. This circular portion typically won't fit over the connector. A box wrench would be preferable to open-end. With open-end, you'll need to be *very* cautious about rounding the corners of the sensor.

As a last tip, if you're replacing only the sensor, unpackage the new one and have it ready in a place you can easily reach while working on the car. Remove the radiator cap to release any pressure-- use extreme caution if hot-- and reinstall. Then remove the old sensor and quickly screw the new one into place. You'll lose only a very small amount of coolant if you can get the new one started quickly.

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Thanks Hyundaitech for you comments. I replaced the ECT sensor and drove it enough so that I'm pretty sure that it went into closed loop and no CEL came back on. Hope that's the end of them for a while. I was not able to use your suggestion on saving coolant. The old sensor was a real bear to get out. I had to remove the hoses in order to get better leverage and wrench angle/movement. I had a half gallon of AF laying around to use. The sensor only had two wires, on this engine there is a separate sender for the gauge. The guy at the parts store tried to sell me the wrong part. He asked me if the car had a gauge or a lite, that made me suspicious so I looked at the part when he brought it out and it was the sender. He wasn't paying attention and had clicked on sender rather than sensor. Computers just let you make mistakes a lot faster. One last question on this car The engine hesitates when starting off cold (if 90 degrees outside can be considered cold). Just doesn't seem to be getting/taking the gas quickly enough. Makes me want to pull out the choke like in the old days. It seems to be OK after a couple of miles. It just had new plugs, coils and wires installed when the initial problem was miss-diagnosed. It also had a "fuel system cleaning" done a couple of months back. I think someone talked my son into that when he first starting having problems with the car. Anyway, what would you suggest as to where I should start looking. Thanks

"hyundaitech" wrote in message news: snipped-for-privacy@localhost.talkaboutautos.com...

Wish there was a way to edit a post afterwards. When I said it hesitates, what I meant was the engine seems to sputter and even act as if it wants to stop but doesn't, but moves slowly. Finally it picks up and moves on out normally.

There's a TSB regarding a reprogramming for something similar to what you describe. According to the TSB 03-36-019,

"The SONATA I4 reprogramming affects the following:

Infrequent minor engine hesitation after an initial cold start (typically the first start in the morning). DTC P0139 (O2 Sensor Circuit Slow Response (Bank 1, Sensor 2)) check engine light illumination diagnosis revised. If this code is set and the rear O2 sensor is diagnosed to be functioning normally, perform this ECM reprogramming procedure."

Expect this to be available at the dealer only.

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Couldn't find that TSB anywhere on Hmaservice.com Not sure that it totally applies since there is no DTC P0139 as stated in the TSB. There are no codes set now (finally), nor pending. In any case would Hyundai do the TSB on a car 9 years old with 91000 miles? I did have the battery disconnected for a while, do you think that maybe after the computer relearns some of its smarts that it may get better? Do the parameters that it uses in open loop mode get modified as it relearns?

It's under the TSB section of Service Information --> Sonata(EF) 1999-->

FL - Fuel System.

The TSB was issued in 2003 for 1999-2002 Sonatas, so it's not that old. I'm certain any Hyundai dealer would be willing and able to update the programming in your ECM for their standard 1 hr diagnostic or labor charge. TSB's are not recalls, they are just service bulletins for the benefit of the service techs in diagnosing and solving problems not covered in the usual service manuals. So your reprogramming is probably a chargeable item, unless somehow it's covered under the 10yr/100K warranty.

Bob

Dealer could get away with doing this under the 8/80 federal emissions warranty. Since you're at 91k, you'd have to pay for it.

It's doubtful that things would change with the relearns, but it probably can't hurt to wait a little bit and see.

The reprogramming was intended to address both a P0139 and the hesitation, but not all vehicles display both. The few vehicles I can recall needing this displayed one or the other of the conditions.

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You're right Bob, its right there. I looked all over that section last nite, they must have just added it today. ;-)

The reason I asked about the computer relearning is because I don't recall this car having the problem before. I gave it to my son 5 years ago so I haven't driven it much since. But I drove it for 4 years before that without any problems. Maybe some part/sensor slowly failing over time, but which one .. No codes set. Do I just have to wait for a solid fail? Its not terribly bad in this hot weather, but I'm concerned that it will be much worse when it gets cold. thanks

Many hesitation issues are due to carboning of the valves. I'd suspect that the reprogram alters the startup fuel mixture slightly to compensate for this.

As for being worse when cold, if it's the hesitation referred to in the bulletin, it should go away. The bulletin specifically referred to a cold start in warm ambient temperatures.

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