QuestionQUESTION: I am having problems with the tranny maybe. Seems to stop all of a sudden like putting on the brakes or like the power suddenly goes out. This seems to happen at slow speeds. I searched around and found out it could be my trans shift solenoid or speed sensors. Is everything located under the air box? If I can take these parts off I can get some at the junk yard replace and try. Also where is the main ground located? Could that be the problem? Got a new battery and cleaned up the terminals. Any help here. Solinoid location? Thanks
ANSWER: Hi, M. I'd like to take this a little slower, if it's okay with you. If your check engine lamp is not coming on, then there's little likelihood that the problem is related to a sensor or ground.
First, I'd like to sort out exactly what is occurring. You say, "Seems to stop all of a sudden like putting on the brakes or like the power suddenly goes out." So I'm going to press you for which scenario more accurately describes the situation. "Like putting on the brakes" describes what would happen exactly if you applied the brakes: that the car will decelerate and stop quickly. "Like the power suddenly goes out" describes a slow and gradual coast to a stop.
When the problem happens, is the engine still running? Does it rev up when you apply the gas? Does the car behave exactly like it's in neutral when you apply the gas? If not, can you describe how it does behave? Has the check engine lamp been coming on? If so, try to have the local auto parts store or someone else read the trouble codes (from the ECM *and* TCM if possible) and report them in your follow-up.
The point of the questions is that I'm attempting to determine whether the issue is potentially brake system-related, transmission-related, or engine performance-related.
To answer your location questions:
-- There are three speed sensors on the transmission. Two on top of the transmission itself and one on top of the differential.
-- The shift solenoids are inside the cover on the front of the transmission.
-- The main ground is on the transmission bolt near the top of the starter.
---------- FOLLOW-UP ----------
QUESTION: I sent a prior follow up question and now this one. I think I found the problem. There is a small wire above the starter. I had to remove the starter to get to it. The wire goes into a black plug and is held into the block by a 10 mm short bolt. I removed the 10mm bolt, but can not pop out the black plug. The wire just before going into the black plug has no coating over the wire so the wire is exposed for about 2 inches. There seems to be two wires twisted around each other in the exposed area. If this is the ground maybe this is the problem. Do you have a part number for replacement wire? How do I pop out that black plug? I tried prying with a screw driver, but it did not seem to budge. What is my next step? Thanks
ANSWER: The item you're viewing is the crankshaft position sensor. If the ECM does not receive the proper signal from this sensor, it won't run properly or it won't run at all. But this is not related to your P0750 code or the fact that the transmission is not operating correctly. You should indeed replace the sensor just because of the poor condition of the wiring, but do not expect that it'll change how the car is operating. Nothing you've related so far indicates that there has yet been a problem with actual signal from this sensor.
To remove the sensor, grab it and twist clockwise and counter-clockwise a few times, and then attempt to pull it out. Usually, the twisting is enough to break it loose without breaking the sensor.
---------- FOLLOW-UP ----------
QUESTION: Thanks for the info. I did change two of the three solenoids on top of the trany from ones I pulled from the junkyard with no change. The two I changed were on top one was the one furthest back and one that was under the throttle or trans cable. You could pull both of them up and out after taking of a 10 mm bolt. The third one on the top had a snap ring and seems like you cannot pull it out but push it inside the trany. This must be the one you have to remove the pan to get out. Correct? You refer to this solenoid as the low/reverse solenoid. Is this also called the trans shift solenoid? When I first start it and I take off there is a slight hesitation then the dash engine light comes on and I can drive it fine for a while. It seems like when the car gets hot and I shut off the car to restart the dash engine light goes off (goes away) but then I have that stumbling problem. I think it stumbles regardless of my speed, but I do not what to go fast when it cuts out suddenly because it is very hash. Do you think I should just take it to a mechanic and ask for an internal trans filter/fluid change and then have them swap in a new solenoid? Do you know what the part number is for this solenoid? I think it is a dealer only item? I also changed the crank position sensor, which did not change the problem. Could it be anything else causing this problem I did see a recall on a problem with MAF electrical signal with vibration of the MAF connector harness. Thanks
AnswerThere are several items on top of the transmission, but none of them are solenoids. You've replaced the input and output speed sensors. The one with the snap ring is the connector for the wiring harness inside the transmission.
Your transmission has several shift solenoids. If you see no other problems, you'll need to replace one of the solenoids, the low/reverse solenoid, part number 46313-39051. I cannot tell you whether this particular solenoid is sold anywhere except Hyundai and Kia dealers. I recommend you register for a free account at www.hmaservice.com so you can view the technical service bulletin relating to this code. It'll provide you illustrations showing, among other things, the locations of each of the shift solenoids so you'll know you're replacing the correct solenoid. I'd also recommend replacing the transmission harness at that time since it's only a small amount of additional work.
Expect that it'll be difficult to remove the transmission pan. There's not a lot of room, you may wish to remove the radiator hoses and fans, and the removal of all the bolts for the pan will be a little tedious.
If you take the car to a shop, you should take it to a shop qualified to do diagnostic work on this sort of issue. And you should ask them to check for the cause of the problem. Potentially, the problem could be anywhere in the wiring between the TCM and the solenoid. It won't be necessary to tell the shop to change the fluid, as it will need to be drained to replace the solenoid. Additionally, the filter in the transmission is not serviceable; the transmission needs to be removed and disassembled to replace it.
Lastly, while many problems can cause the vehicle to not accelerate properly, problems with the mass air flow sensor will not cause the diagnostic trouble code you have. Additionally, whatever is causing this trouble code (probably the low-reverse solenoid) will also cause the TCM to place the transmission in third gear, making acceleration at low speeds very slow.
