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Trans_ Service
Trans_ Service, ..................
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Pavlin, I was just reading this exchange as I have the exact

Customer Question

Hi Pavlin, I was just reading this exchange as I have the exact same issue with my 2009 Pontiav Vibe 2.4l, 5 speed transmission with 150k miles. I have replaced the input speed sensor and the problem returns after driving for 15 miles or 20 minutes at highway speed or 5th gear driving, seems to clear check engine light on it's own and may not return during short duration and in town slower speeds, but will return with 5 gear and possibly temperature. While car is warm and driven at highway speeds, it will not shift to 5th gear. Let it sit for 1.5 hours and ok again until warms up due to highway driving. The Trans fluid was replaced at 100k miles. Would it possibly help changing fluid again? Thank you
Submitted: 1 year ago.
Category: Transmissions
Expert:  ebrock63 replied 1 year ago.

HI,

I am sorry that you have not been helped yet. I just came online and saw your question

Is the check engine light on, and if so, have you had it scanned for fault codes? If so, what are they?

Have you checked the fluid to see if it is black or burnt smelling, or low? Or if there is metal shavings in the fluid

Please remember that I am not there to, therefore I rely on you to provide as much detail as possible. On occasion I may need to ask for more information or clarification

Customer: replied 1 year ago.
Good morning Eric, yes the check engine light is still on, it does go off on it's own, but will return after driving for a while at highway speeds. Every time I have had the ODBII gode read, the only code has been PO717. The trans fluid was changed at 100k miles, and is no longer bright red, a little discolored, but doesn't smell burnt. Would new fluid help this intermittent problem? Thanks, ***** *****
Expert:  ebrock63 replied 1 year ago.

HI,

Thanks for the added information. Ok, with P0717 fault code and the symptoms, it wont be the fluid and wont be internal. It is strictly in the electronic transmission control system on the input speed sensor circuit.

Since you have replaced the sensor, it is either a short or open in the wiring harness or a failure of the input sensor circuit in the PCM(powertrain control module)

If you have a digital voltmeter and feel comfortable doing some testing, I can upload directions for testing the wiring to determine if it the wiring or the PCM at this point

Customer: replied 1 year ago.
I can perform these test. Please send, thank you
Expert:  ebrock63 replied 1 year ago.

HI,

Ok, I have uploaded the testing procedure and pcm connector pinout needed. Make sure to do the resistance test for the sensor as it could be defective out of the box

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Customer: replied 1 year ago.
Hi Eric, I performed the ohm testing of sensor and ecm wiring harness. The only problem is with step three, instructing to remove connector and take ohm reading on c26, pin 1 and 2, this doesn't appear correct, as I read 22k ohms on the connector back towards the ecm. If I read the speed sensor pins 1 and 2 I receive a reading of 634 ohms. If I follow step 4, read c24 pins 124 and 125 back toward the speed sensor I read 641 ohms, and no continuity to grounds from either pin. Please realize the problem is intermittent and vehicle is cold, hasn't yet been driven today. Thank you, ***** *****
Expert:  ebrock63 replied 1 year ago.

HI,

Ok, drive it around today for a while and when you get home and is still warmed up from the driving, repeat the tests and let me know the results

Customer: replied 1 year ago.
Ok Eric. I'll drive until problem resurfaces, sometimes takes 20 miles or so. Obtw, step 3 of the wiring and sensor test was to read the sensor and not connector right? Thanks, ***** *****
Customer: replied 1 year ago.
Also is there some specific voltage reading from ECM pins 124 and 125 I should be looking for?
Expert:  ebrock63 replied 1 year ago.

HI,

Both are input signal wires from the sensor - one is low signal and one is high signal - so there is no voltage output from the ecm on them.

Customer: replied 1 year ago.
Eric, sorry, still confused about step 3, which states disconnect connector from sensor and measure the c26 connector, pins 1 and 2, if you don't have 560-680 ohms replace the speed sensor?
Since I have driven the car here are the results. I started the car, no check engine light, all was sifting fine for 18 miles, then light came on, after I came to stop and started driving againg, the shifting problem was back, 1st to second or third was rough and no shift to 5th. Now that I have retaken measurements, I'm doubting my initial results. I came back home to remeasure ohms. No ohms across pin 1 and 2 of speed sensor where I thought I had seen 634 prior when cold, When c26 connector is back in place on speed sensor, no ohms across 124 and 125 on c24 at ecm where I thought I had measured 641 ohms when cold.
After closer look at wiring harness, I now realize c24, pins 1 and 2, white and red wires, are not the same wires as c24, 124 and 125, black and yellow?
Maybe I should wait til car is cold and take measurements again. Please advise
Thank you, ***** *****
Expert:  ebrock63 replied 1 year ago.

HI,

Should be the same colors. I rechecked my schematics. The wiring colors dont show a change on the actual wiring diagram, but for some reason my ecm connector pinout doesnt match. I will need to opt out and see if another expert has the correct ecm pinout

Customer: replied 1 year ago.
Hi Eric, I was able to determined that c26 1 and 2 is actually c24 101 and 102, not 124 and 125. I read 22k ohms across c26 1 and 2 when c24 is plugged into ecm. I see no problem with continuity in wiring harness. I read .7k ohms from across the pins of the speed sensor. Thanks, ***** *****
Customer: replied 1 year ago.
when I took my initial ohm readings across the speed sensor pins at the beginning of this process my reading most likely was .634k, not 634 ohms. Thanks, ***** *****
Expert:  cloe0626 replied 1 year ago.

seems like a failure in the pcm

Customer: replied 1 year ago.
what is your suggestion to resolve?
Expert:  cloe0626 replied 1 year ago.

the only thing to do to solve the problem is to replace the pcm

Customer: replied 1 year ago.
This recommendation is based on what findings, as we did not have a correct ecm wiring diagram and trouble isolation. testing and inspection process?
Customer: replied 1 year ago.
Could I have someone contact me regarding my mechanical issue and support. As you can see, the last note indicates my unresolved issue has been reassigned to a new expert on 10/10, with no contact. Thank you
Expert:  Trans_ Service replied 1 year ago.

Hello. Different expert here. Please allow me to assist you. The P0717 code relates to a "turbine speed sensor no signal condition". Toyota is aware of this issue and have issued a replacement wire harness that addresses this problem. You need to go to your local Toyota dealership's parts department and order part number 82126-02050 and install this wire harness. This should rectify the problem.

Customer: replied 1 year ago.
OK, I have called to check with local dealership, part is being ordered, $31, should be in tomorrow morning, I'll get back just as soon as I have installed. Thank you.
Expert:  Trans_ Service replied 1 year ago.

You are very welcome.

Customer: replied 1 year ago.
Good morning, I now have the new c26 connectorized pigtail and ready to install, no wiring instructions were included. Noticed that the wire colors are not the same. My existing c26, pin 1 and 2, are white and red. New connector wires are black and yellow. Also, the wiring diagram I was sent by Eric, on Oct 10, "b4c23fd7-b7a6-4b05-b7c8-2d31aa42feec_2015-10-10_083305.png" indicated c24, pins 124 and 125 were the wires to test ohms back towards c24. Those wires, pins 124, 125, are black and yellow, but not connected to c26, 1 and 2. The white and red wires terminate on c24, 101 and 102? Please advise how to wire. Thanks, ***** *****
Expert:  Trans_ Service replied 1 year ago.

The replacement harness connects at the speed sensor, not at the computer. Black is NT+ Yellow is NT-

Customer: replied 1 year ago.
Thank you for your reply, I realize where it connects, was asking what wire splices to what wire, considering they do not match in color. ie: Blk to Wh, Y to R? Thank you
Expert:  Trans_ Service replied 1 year ago.

Black to red yellow to white

Customer: replied 1 year ago.
Thanks
Expert:  Trans_ Service replied 1 year ago.

you are welcome.

Customer: replied 1 year ago.
I installed new connector and just returned from a 22 mile test drive, highway speeds and in town traffic speeds. All seemed good until check engine light returned along with hard shift issues. I'm a bit disappointed and feel this has been a process of elimination without tangible proof of fault cause. ***** *****
Customer: replied 1 year ago.
What do you suggest now.
Expert:  Trans_ Service replied 1 year ago.

Assuming that your speed sensor is good, and properly positioned, the only other possibility is a flaw on the the drum that has the high and low cut outs that the speed sensor measures. A cracked tooth, a void, a missing tooth, or some other type of issue that does not allow the sensor to read each and every one of the teeht on the drum is the only other possibility that I can think of, other than an possible ECM failure (which is extremely rare). A good tech with an oscilloscope can measure the NT signal and tell you if it is compromised. That is what I would be doing next if this vehicle was in my shop. You may have good continunity form the senso tot the ECM, but, if the signal is distorted, weak, or resetting due to a mission or cracked drum tooth, that is what needs to happen next. If it is determined that the NT signal is bad at the sensor, your best recourse is to replace the transaxle. Replacement of this unit is NOT recommended because no one has the proper tools in their shop to properly reset the clearances. Not even a goo transmission shop has these tools. That is why Toyota does not allow us to rebuild the units in the shop. The clearances are super critical. If one cannot set the clearances properly, he will not have a proper rebuild and it will have problems.

Customer: replied 1 year ago.
Thank you for your detailed explanation. I just rechecked the Odbii codes and in addition to the same po717, I now have po102 and po113, haven't seen these before, but may not even be relevant. All along, this vehicle has performed flawless for 150k miles, and even now, when driven cold for first 20 - 25 miles, not a problem noticed. Probably would also be unlikely that the old speed sensor and new Toyota OEM sensor would have identical problems. Also very unlikely that the ECM would have no other fault codes or indications of trouble other that the speed sensor circuit. I'm assuming it is also very rare to have a flaw in the drum high and low cut outs, for no apparent reason or cause like being in an accident or some type of abuse to transmission? Do you think Toyota Dealership Service has the ability to perform the oscilloscope testing you mentioned?
Thank you, ***** *****
Customer: replied 1 year ago.
Just a question re: oscilloscope reading testing of speed sensor drum, is it possible to perform this testing while vehicle is sitting stationary and not during driving, shifting conditions?
Thanks, ***** *****
Expert:  Trans_ Service replied 1 year ago.

To get the best result, you do the test twice. One driving, the other stationary (wheels off of the ground). If you want to do it stationary, that is OK. Run the RPM slow to start, then gradually increase. What you are lookign for is a drop in the waveform. That would equate to no NT signal. (ie an internal issue or faulty sensor)

Customer: replied 1 year ago.
Sorry for delayed response, I have unexpectedly been out of town for the last week. Therefore have not made any further progress on the car problem. I certainly appreciate your help and consideration. Although, I have been given more thought to the specifics of the problem since our last exchange. While the problem is intermittent, it is very consistent and predictable. When driven cold, or not driven for a couple of hours, all is fine with or without the check engine light being active, the problem resurfaces after being driven for 22-26 miles. Even at highway speeds in 5th gear, all is good, then all of a sudden you can feel a slight pause, or if slowing down to a stop, the downshift is hard shifting and upshifting seems to only include 1st, 3rd and 4th and will remain this way until allowed to sit for a period of time.
My reason for re-outlining some of these observations is I'm trying to realize how the faulty "drum" theory involving some deformation, having tooth missing or flat spot, would not be a consistent, all of the time condition, for the ecm not reading the speed sensor correctly?I realize this problem that I have is apparently not a common problem, clear cut and dry issue to diagnose. Was just hoping the additional details may allow help to figure out.Thank you. ***** *****
Expert:  Trans_ Service replied 1 year ago.

Thanks for the reply. Assuming the speed sensor is good (a new genuine part, not aftermarket), and the wiring is all good, thsi leads us to ECM issues, or that what the sensor reads issues. For all we know, we are chasing the wrong problem. Since this is obviously a heat related issue (OK cold, starts up when hot) , perhaps we have sticking valve or valve actuators (solenoids) in the valve body. FOr the money it takes, and with the thinking of avoiding speculation on an replacement ECM, why don't you go and have the transaxle flushed? It should only cost about a hundred dollars or so (versus 800 for an ECM). The flush and fluid conditioner might clean off the valves and rectify the condition. You might be getting the code because the solenoids are sticking. If this car was in my shop I would be doing a complete flush before anything else at this point.

Customer: replied 1 year ago.
Thank you for your recommendation. I like the plan, I will get this done and get back with you.***** *****
Expert:  Trans_ Service replied 1 year ago.

ok please let us know

Customer: replied 1 year ago.
I had a Toyota dealership perform a complete transmission flush service. Test drove vehicle for 58 miles combined highway and in town driving, then and only then, same problem reoccurred, check engine light and limp mode and shifting issues. What to do next?
Expert:  Trans_ Service replied 1 year ago.

You need to take the car to the dealer service dept and leave it overnight. The need to hook up the test box and drive it, monitoring the real time data stream. When the problem occurs, there should be some evidence resulted in the data read outs. Something is dropping out, sticking, or some other internal issue. A total lack of data would indicate a problem in the electronic control unit. A scanner will not do real time data. You need to hand this off to the professionals with the right test equipment.

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