[Resolved] - Toyota Passo 2008 - Transmission Problem - Lahore

[pwuser162265417286]

Hello Pakwheels,

I am having problem diagnosing a transmission problem. I am from Lahore.

Issue Description: When driving I hear engine rev (like someone pushed down on gas pedal) just for 1-2 seconds and right at that time car transmission would shift. Right now it happens exactly at 40km/h (I hear slight engine rev for a second and along side that rev car changes the gear) and same thing happens at 60 Km/h.
Depending on how hard I push down on the gas pedal gear changing time varies.

Car Details:
Toyota Passo 2008

More Details:
-Last week I decided to go ahead and swap out my car head assembly and gear box, because both car engine and transmission were not in good condition and burning their respective oils.

-After installing kabli head-assembly and gearbox I am encountering above specified problem.

-The mechanic that installed both things and the guy I bought it from both recommended to keep driving it for at least 1000 km and insisted that this would go away with little time.

I knew the issue is not going to go away automatically still kept the car with over the weekend. Today I went back to him and demanded a different gear box. After some argument he agreed and provided with a different gearbox.

Alas after I got the gearbox swapped out the problem persists. The engine revs exactly at 40km/h and again at 60 Km/h just like before. Now I am under impression that this is not a gearbox problem.

I have been researching internet for this and erratic shifting can be caused by faulty solenoid or bad speed sensor.

I can go again and demand another gearbox, but the process of swapping out gearbox with new gear oil every time is costly and I am worried now that even third time might cause the same problem.

Can someone please recommend a transmission expert or electrician that can verify for me if this is a sensor/solenoid issue or indeed transmission issue and I should opt for replacing gearbox.

Thank you

[aziz.rehan]

Is car giving check engine light?

[pwuser162265417286]

No Car is not showing Check Engine Light or any other check indicator.

[zakiuddin]

Are you sure the check engine light is working? Get it scanned regardless and post the codes if any. Even if there is no confirmed code there must be something under pending codes.
and go for a high end scanner. The cheap OBD scanners ability is usually limited to Engine only or sometimes complete Powertrain.

[pwuser162265417286]

Do you know any good Car Electrician in Lahore?
Mostly electrician here says that how can we check if engine is not showing any code.

[zakiuddin]

sorry i don't know any Electricians in Lahore but the point is, that there has to be a code if there is a problem with your car. That being said, not all parameters in the car are monitored by ECU
Mechanics are right if they say that they can't fix a car without any error code but either there has to be one or you are missing a piece of the puzzle.
Does your Speedometer and RPM meter works fine when this happens?
so let me understand your original gearbox did not have this gear change issue right?
and You got it after the 1st transmission swap?
and 2nd transmission swap did not fix the problem?
If that's the case, then chances are:
1. The 2nd transmission swap was never done. Are you sure the gearbox was changed in 2nd swap?
2. The mechanic forgot to plug a connector back in both 1st and 2nd swaps. Not sure why it's not registering on the ECU.
BTW, did you get a computer scan on your transmission? no errors?

[rajaatta]

Ok this problem does occur when Speed NT sensor is mismatched on new transmission your TCM is not recognizing the Torque converter speed sensor input properly and thus doing this behavior.
The simple fix for this solution is to get back the original speed sensors from your old transmission and get them installed and your problem would be solved.

If you have access to scan tools then observe speed NT reading at idle and during driving.
And post the values here then we will be able to figure out what's actually happening to your vehicle.

[pwuser162265417286]

Thank you for your reply.

-Passo 08 and does not have rpm meter.
Speedometer is working fine when the problem occurs.

-Yes, the old transmission had a completely different problem not this one that why opted to change it.

-Transmission was indeed swapped, I was there in person.

-I am on my way to electrician to get it scanned perhaps it will show some fault code that is not triggering check engine light for some reason.

[pwuser162265417286]

Thank you for the reply.

I am going to electrician right now to get car scanned.
If they find anything out of the ordinary I will mention here.
I do have access to old transmission in case nothing comes up in scanner check, I will try to get old speed sensor installed.

[pwuser162265417286]

Update.

The scanner didnt show any error.
They connect the scanner and took a drive as well but still didnt show any code on scanner.

Electrician said that there is no electrical or sensor issue.

Now I am taking it back to person who installed the transmission to see what he will say.

[SpeedDemon]

If this is a conventional automatic, you are facing a delay or extended interruption in power delivery when the tranny shifts gears. This could be due to low oil pressure, improper solenoid operation or just worn out parts inside the transmission like clutches (not the main clutch as there is none and a torque converter is there).

[pwuser162265417286]

I am going to different electrician now to get second opinion.
@SpeedDemon It could be solenoid, ECU, speed sensor or transmission itself, real issue is finding someone capable and willing to diagnose this.

According to electrician its gear fault and according to mechanic gear is in fine condition and after 2nd swap same problem indicates that issue is somewhere else but is willing to change the transmission again if I want and I am ready to bear the cost.

Can you recommend any expert in Lahore that can pin point this issue for me?

[SpeedDemon]

Suntech Automobiles and Engineering.
Auto repair shop in Lahore
Address: Opposite، Maulana Shaukat Ali Rd, Kot Lakhpat, Lahore, Punjab
Closes 6PM
Phone: 0300 8441213

I have heard good things about them. Seem to be very good with Vitz issues.

[pwuser162265417286]

@SpeedDemon Thank you.

I took the Car to Iqbal Autos (Chuburji). They didn't drive the car or anything and said that You can try changing the TCM Kit. If it works then great otherwise you will have to try with Mechanic again.

The Kit replacement is around 10k to 15k.
I think I will visit Suntech Autos first.

[rajaatta]

Good job now this proves that here on pakwheels no matter how much you advise the people on accurate diagnosis they will not read the advises properly and keep banging their heads with local technicians.

[pwuser162265417286]

Thank you for advice but there is no need for Sarcasm.

As for your advise I did mention speed sensor compatibility to every electrician and mechanic I made a stop at, most of them are not interested in this solution taken from internet and have the attitude of "we know what we are doing", short of going under the hood and replacing speed sensor myself I can only ask them.

Regardless I did get it swapped today with original gear sensor but the problem still persists.

[zakiuddin]

Does this gearbox have internal TCM? If so use the TCM from your old gearbox.

[pwuser162265417286]

No it does not have Internal TCM.

I have been looking for replacement TCM/ECU Kit and so far no luck finding it.

[rajaatta]

You have missed a key component and that was to get the reading of SPD NT in transmission section by hooking up the scan tool and get the live readings. Sorry mate but you are a fast reader.

[pwuser162265417286]

Sir I don't have equipment to take reading myself and the people here don't give their reading tools in my hand to see it.
If you know any Mechanic/Technician in Lahore that works like that then please let me know.