[lasuntela]

On the 29th of December, 2021, I was driving around 5 pm, and the Check Engine light came on with the VSA and TRAC ON/OFF, the vehicle began to vibrate, so I pulled over and switched off the engine. After about 10 minutes, I switched on the engine and the lights were off. So I drove it over to the Auto Zone for a scan. The report came out as P0304 - Cylinder 4 Misfire Detected. I had the spark plug in cylinder 4 changed immediately. I drove the vehicle around for about five minutes but under 35mph. Felt all has been resolved.

On the 30th of December, 2021 at about 6:20 am on the Interstate, the vibration began again and this time I was at a speed of about 65-70mph when the lights came on again so I tried reducing the speed and pulled over to the side of the road. I switched off the engine and parked for about 25 minutes. By that time the lights had gone off, so I drove it for about 14 minutes to the Toyota dealership.

That was where I got the information that the vehicle need Torque Converter and that it was advised that the Transmission be changed due to the mileage. Thus I took the minivan away to get a second opinion. On the 7th of January, I was told by the second mechanic that it was not the Transmission but a need to put in a supplement Tube Lubeguard, thus it was done at $81:33. The minivan began to function well but because there was an appointment made with a third technician set up already for the 10th of January, 2022 I decided to have a third option.

So on the 10th of January, the 3rd person took the minivan in for a diagnostic. After running the diagnostic and running the vehicle around for over 30minutes, they ascertained that there was nothing wrong with the Transmission. A bill of $99:41 was incurred for the diagnostic. Between the 10th of January and now, the vehicle had run more than 192 miles (six trips from Duluth GA to Gainesville GA) without any issue. Twice between the 10th and 16th, it happened again twice and each time I switched off the engine and switch it off the lights go off and it runs again.

By the 16th of January, the lights returned and the stuttering began again. The technician changed the spark plugs, coil around cylinder 1 and injector, then it runs well for few minutes and the check engine light and VSA TRAC light comes on again. Now we don't know what to do. Please can someone help, what else can be done to stop this stuttering and to reset everything as I can not run the minivan-like before again.

 

[SilverMachine]

This video has some good suggestions:

 

[ericreyn]

Your assuming I would guess that its the same code every time the check engine light comes on.
It might not be a bad idea to buy a cheap code reader and store it in your glovebox so you can read these as necessary.

 

[BillG]

So, my understanding is that the VSC/TRAC lights come on when there's an issue with the wheel speed sensors or the control module(s). It's possible that there was a mismatch between the detected wheel speed and the transmission speed not matching, but I didn't think the Gen2 had any integration with engine/transmission speed for the system and just used the 4 wheel speed sensors. If the VSC/TRAC lights come on while not moving, you likely have an ABS code being thrown. ABS codes are not found on the standard cheap code scan tools. You need a specific code reader that can pull ABS codes or need to follow the jumper procedure on the OBD connector to get the code from the lights.

Now, it's entirely possible that you have several issues and it's also possible that one issue caused other issues. The "vehicle began to vibrate" can be any number of things. It's odd that the dealer said you needed a new TC and transmission and then the next guy "fixed" it with an additive. In general, additives are NOT worthwhile. They often cause more damage than they fix and, in many cases, your best hope is that they do nothing. The transmissions are touchy in the Sienna and anything other than the specified fluid, clean and relatively fresh, filled to the proper level will cause issues. Personally, if my transmission was acting up, I would start with a transmission flush plus a filter change. I would also pull the engine codes PLUS the ABS codes. Lastly, I'm not sure why the technician replaced "the spark plugs, coil around cylinder 1 and injector." Personally, I'm guessing, after your P0304 was fixed from a new plug, you got a P0301 (Misfire in Cyl 1) which is the catch-all code for misfires, dirty MAF, clogged air filter, or anything else which causes a non-descript combustion issue. So, to that end, I would probably replace the air filter, clean the MAF and check the short and long term fuel trims to see if it's running rich or lean. I would assume that would point to the issue right away, but, if all that checks out, I would consider the possibility that the first diagnosis was correct and that the torque converter is somehow malfunctioning and causing the issue. There are also a number of other things that can cause misfires which may be causing the issues you're experiencing.

 

[bencahill]

Just to be clear, from my knowledge, if the check engine light (CEL) comes on, the VSC and TRAC lights will come on as well. So if all three are coming on at the same time, I would focus on the CEL. I agree with ericreyn; you need to get a code reader and keep it with you so you know what the code is that's being thrown each time it happens. If you report back with the codes after it happens another time or two, we should have better suggestions on how to proceed.

 

[circus]

A similar thing happened to my PT Cruiser (bought it that way, cheap). Randomly ran like crap. Code 303. Swapped the injectors on cyl.3 with cyl.4 which caused code 304 so I knew it was a bad injector. Cost me $12 and a trip to the junk yard. Bought a spare while I was at it.

 

[goldenpiggy]

This happened to me on my 2007 XLE FWD. It turned out to be one bad COP coil.
Given the mileage, I changed all 6 coils and spark plugs. Problem solved.

 

[lasuntela]

This video has some good suggestions:

Done, thank you

 

[lasuntela]

Your assuming I would guess that its the same code every time the check engine light comes on.
It might not be a bad idea to buy a cheap code reader and store it in your glovebox so you can read these as necessary.

No, I didn't assume a thing. Each time the codes come up. I have them read but the codes that stayed stubbornly is the P0301.

 

[lasuntela]

This happened to me on my 2007 XLE FWD. It turned out to be one bad COP coil.
Given the mileage, I changed all 6 coils and spark plugs. Problem solved.

Great!

 

[lasuntela]

So, my understanding is that the VSC/TRAC lights come on when there's an issue with the wheel speed sensors or the control module(s). It's possible that there was a mismatch between the detected wheel speed and the transmission speed not matching, but I didn't think the Gen2 had any integration with engine/transmission speed for the system and just used the 4 wheel speed sensors. If the VSC/TRAC lights come on while not moving, you likely have an ABS code being thrown. ABS codes are not found on the standard cheap code scan tools. You need a specific code reader that can pull ABS codes or need to follow the jumper procedure on the OBD connector to get the code from the lights.

Now, it's entirely possible that you have several issues and it's also possible that one issue caused other issues. The "vehicle began to vibrate" can be any number of things. It's odd that the dealer said you needed a new TC and transmission and then the next guy "fixed" it with an additive. In general, additives are NOT worthwhile. They often cause more damage than they fix and, in many cases, your best hope is that they do nothing. The transmissions are touchy in the Sienna and anything other than the specified fluid, clean and relatively fresh, filled to the proper level will cause issues. Personally, if my transmission was acting up, I would start with a transmission flush plus a filter change. I would also pull the engine codes PLUS the ABS codes. Lastly, I'm not sure why the technician replaced "the spark plugs, coil around cylinder 1 and injector." Personally, I'm guessing, after your P0304 was fixed from a new plug, you got a P0301 (Misfire in Cyl 1) which is the catch-all code for misfires, dirty MAF, clogged air filter, or anything else which causes a non-descript combustion issue. So, to that end, I would probably replace the air filter, clean the MAF and check the short and long term fuel trims to see if it's running rich or lean. I would assume that would point to the issue right away, but, if all that checks out, I would consider the possibility that the first diagnosis was correct and that the torque converter is somehow malfunctioning and causing the issue. There are also a number of other things that can cause misfires which may be causing the issues you're experiencing.

This is quite explanatory. Thank you

 

[lasuntela]

A similar thing happened to my PT Cruiser (bought it that way, cheap). Randomly ran like crap. Code 303. Swapped the injectors on cyl.3 with cyl.4 which caused code 304 so I knew it was a bad injector. Cost me $12 and a trip to the junk yard. Bought a spare while I was at it.

Really? That cheap??

 

[lasuntela]

Thanks to everyone who had commented. I am so grateful.
I took the minivan to another Toyota dealership where I paid for a full diagnostic to be carried out. They swapped the plugs and did a few other things and the codes and misfiring are gone. They however said, they cannot say if it will return at 10 miles distance or at 1,000 miles distance but that if it does come up again I should bring it back, and then they can read the new codes and advise if any change or repairs need to be done. For now, I drive it at a maximum of 50mph and it's driving well, I pray it will be the same when I hit the interstate with it soon. Thank you again.

 

[edmonddragut_3609]

Agree with some of sayed before. best of the best will be a full tune up, injectors check and replace if necessary and why not throw also in play a compression check. you may have a piston ring problem.

 

[RandyS]

Thanks to everyone who had commented. I am so grateful.
I took the minivan to another Toyota dealership where I paid for a full diagnostic to be carried out. They swapped the plugs and did a few other things and the codes and misfiring are gone. They however said, they cannot say if it will return at 10 miles distance or at 1,000 miles distance but that if it does come up again I should bring it back, and then they can read the new codes and advise if any change or repairs need to be done. For now, I drive it at a maximum of 50mph and it's driving well, I pray it will be the same when I hit the interstate with it soon. Thank you again.

I hope you are not experiencing what I have been chasing for several weeks on my 2008 van with 212 k miles. Mine was a PO302 misfire code. Changing / swapping plugs, coils & injectors did not stop the intermittent misfire code and engine shake. While the shake was short lived, I knew something was wrong. We did pretty much all of the same diagnostics you described. The compression tests were inconclusive. The final straw was a leak down test on all of the cylinders. Cylinder #2 showed a leak, indicating a head gasket failure. Oh yes, and a $4,000 engine repair bill on a 14 year old van. Here's hoping that the dealer found your issue.

 

[compac]

Same warning lights but diff code,
2008 Sienna V6


No rough running. But turned out to be a bad O² sensor.
First tried just a warning reset,
Tried to cleaned the fuel cap, and then place it.
No joy.

A couple $100,
$300 to Dx and replace the 1 bad one. There are multi 4? Sensors. It was the #1 front of engine area pointing twds radiator.


Prob has not returned now 6 months, mult 1000s miles. Low miles 75000

Oxygen Sensor (O2) - Rich Or Lean Engine Codes, What To Check

Replacement of a good Oxygen Sensor (O2), is a common mistake made by (DIY) mechanics all the time. Therefore, before replacing any of these oxygen

dannysengineportal.com

HTH

 

[rangerbentman]

This appears to be the most recent thread of the VSC. Mine just came on today for no apparent reason. My code reader has been given away so I will take it to my mechanic as he has all the tools that I could only dream about . My hands do not function like they used to hence the mechanic. So what i take from all the replies is the VSC can be triggered by several problems not necessarily something related to brakes. Correct me if I am wrong? According to the manual I am to take it to Toyota so i would imagine the manual to be heavily biased towards the profits of the Toyota empire?
2008 Sienna XLE awd, 140000 miles. Just had the engine checked for bad gas mileage , a couple cleanups , new sensor for temp and new thermostat put in. Runs better till now when the VSC has just popped up.

 

[Johnny5]

Might be unrelated but I had some vibration and VSC lights after replacing my intermediate steering shaft. The vehicle think it's loosing control and starts applying the brakes in an ABS like fasion. Have you tried reseting the yaw sensor? The procedure is called a zero point calibration.

 

[rangerbentman]

hmmmmn Youtube to the rescue?

I would prefer to know the cause as well as the cure?

 

[BillG]

This appears to be the most recent thread of the VSC. Mine just came on today for no apparent reason. My code reader has been given away so I will take it to my mechanic as he has all the tools that I could only dream about . My hands do not function like they used to hence the mechanic. So what i take from all the replies is the VSC can be triggered by several problems not necessarily something related to brakes. Correct me if I am wrong? According to the manual I am to take it to Toyota so i would imagine the manual to be heavily biased towards the profits of the Toyota empire?
2008 Sienna XLE awd, 140000 miles. Just had the engine checked for bad gas mileage , a couple cleanups , new sensor for temp and new thermostat put in. Runs better till now when the VSC has just popped up.

Countless things can trigger the VSC/TRAC/ABS lights. If you have no check engine light, you'll need a scanner for the ABS system too. I think trans codes can also cause the problem. There's absolutely nothing wrong with paying a mechanic to do the diagnosis AND the work. Although, I'm a firm believer that everyone should own the mid-range OBD scanner which can capture live data and read ABS codes. It bugs me that, without a scanner, I have to call and make an appointment (often 2-3 weeks out in my area) and have no idea what the nature of the issue is and if it's safe to drive.