01-02 Zero Point Calibration Trac / VSC - Sharing and Seeking

All in the same thread! Yes, you get help AND hopefully I get answers. FOR FREE! Can't beat that! LOL ....

Okay, comic relief aside, I just introduced myself in the New Member Introductions Another 4R in Florida and this is my first actual post:

The previous owner of my 2002 4R experienced the dreaded Trac / VSC lights coming on. After she went to several mechanics who hadn't a clue how to resolve it even with the OBDII scanners, she drove with the lights on for years with no issues. When I purchased it a bit over a month ago, it also had a CEL code which ended up being a broken o-ring seal on the gas cap. Problem solved on the CEL.

As I researched the Trac / VSC issue I was hard pressed to find accurate information regarding this that actually worked for this vehicle. All of what I found in forums and YouTube related to shorting out terminals from the OBDII port. I did other things such as remove and clean the ABS sensors and search for any electrical shorts in the wires, etc.

But ... what I found is that particularly with the 01-02 model years there is a different method for calibrating the VSC. I've attached a short write-up; I did not write it and forgive me I don't know who to credit for it, it is only signed "FOG". Possibly a member of this forum? Chime in!

I did this last week. Using the diagnostics port under the hood is where this is done for the 01-02 model years. I don't know why, maybe someone else knows. But nevertheless this worked. I've attached the 2 page write up.

Now, jump forward to today. Trac / VSC lights came back on. Back up again to a few days ago, the weather has been absolutely clear with no precipitation. I've driven on highways, back roads, over bumps, etc. But again to today, it was a rainy morning. The lights came on while I was on the highway at about 70mph a few minutes into driving.

I have not calibrated again, but plan to this evening. So my question to anyone experiencing this is what may have happened here. Why did the lights come on again? Note, no ABS light came on, although I should mention that was on as well when I bought the truck and went off with the calibration.

There you have it! Open for discussion. Thanks!

 

I forgot to add the procedure for calibrating the deceleration sensor. I am quoting from another site and providing a link I'm sure is forbidden although I am just trying to give credit where it's due. Here is the TOTAL procedure in written format:

"CALIBRATING YAW and DECELERATION SENSORS ON [2001/2002] 4RUNNER
The VSC TRAC system uses two sensors a steering angle sensor hooked to the steering wheel and a yaw rate sensor. The yaw rate sensor needs to know what the normal angle of the car is side to side, front to back and front left to right rear and left rear to front right. It needs to know this to know when the vehicle is yawing (IE skidding).

Recalibration is simple to perform and all you need is a level surface and a 4-inch long jumper wire stripped at both ends.

(Note: [The OP believes] the calibration has to be done in the following order.)

To reset the VSC TRAC have the vehicle parked on a level surface both front and back and side to side (this is very important).

(Note: Do not put any weight on the vehicle that at any time could offset it from being level)

This is the procedure for calibrating the YAW SENSOR:
1. Open the DLC-1 diagnostic port on the driver side in the engine compartment
2. Turn the ignition on
3. Using the jumper wire connect the E1 and TS pins 4 time or more within a 8 second period
4. Check that the VSC TRAC light on the dash came on again, it should be on for several seconds and then go out
5. Turn the ignition off
6. Wait a few seconds, then turn on the ignition and wait for the VSC TRAC light to go out

This is the procedure for calibrating the DECELERATION SENSOR:
1. Connect terminals E1 and TS again on the DLC-1 diagnostic port
2. Turn the ignition on
3. Check that the VSC TRAC light is on for about 4 secs and then starts blinking at 0.13 sec intervals
4. After the light has been blinking for 2 secs turn the ignition off
5. Remove the jumper wire"

Like I said in the previous post, after this procedure the the lights were off until since the rainy drive to work this morning, the lights came back on, minus the ABS light. I did not have the chance to recalibrate this evening. Hopefully tomorrow.

 

Could it be a sensor? I know that a faulty ABS sensor will throw codes.

Another random idea.. Is the brake fluid reservoir full? I think it will also throw codes if it gets low.

 

I'll admit when I pulled the ABS sensors and cleaned them I did not test them so that will be something to look into. And yes, the brake reservoir is full. No CEL codes, no ABS light ... just the VSC/Trac lights are on.

 

Ok, just thought I'd mention, as that's easy to overlook.

Have you tried a hard reset on the ECU?

I recall having an issue with the transmission on my '03 that I solved by shorting the battery cables (after disconnecting the battery!) Also, this will reset everything to factory settings, so it can cause some complications.

For instance, mine wouldn't run after the timing belt service at around 240K miles. It turned out that the ECU had been compensating for a dirty throttle body, and once it was reset, it wouldn't stay running. The solution was to clean out the throttle body.

Just some more stuff to think about.

 

May just give that a shot. Thanks! Are there any anti-theft codes I should be aware of, for instance the radio? Any other relearn/reset procedures after shorting the cables?

I also just thought of something else based on your suggestion. Wheel bearings. I think the fronts are going due to the rumble I hear upwards of 60+mph. Might that have an affect on the ABS sensor(s)? But again, the ABS light is NOT on. - Damn challenges; I love them. LOL

 

Honestly, I'm not sure about any anti-theft codes, etc. I just used the trick to get rid of codes on my '03.

Usually, the window switches would act weird for the first couple of drives afterwards. The auto up/down features would need to relearn or reprogram themselves. I'm sure there's probably a proper procedure for this, but I never figured it out. Eventually, everything would just work again.

You can also do this reset by just disconnecting the negative cable from the battery for a half hour or so. This is probably the safer way to do it.

 

@Thatbassguy Thanks dude. I did the hard reset on Wednesday evening by disconnecting the negative battery terminal for over 30 minutes. I've driven the truck for two days now with no issues. Note though, it has been clear weather again. With rain in the forecast we'll see if the lights come back on.

As a side note, I replaced a few vacuum hoses under the hood (broken and brittle). More of an evaporative emissions issue I'd think.

 

Just a reminder, those TRAC/VSC lights literally pop on for anything. Bad O2 sensor? TRAC/VSC lights. Leak in Evap system? TRAC/VSC lights.

So yeah, fixing the vac lines might have helped things. But you should get a CEL light though. Keep us posted.

 

I had been getting intermittent CEL codes that I was tracking with regard to the evaporative emissions. I'd try a few things, clear and watch. For now, seems all is well. But yeah, I expect to see lights again given the history of this design, LOL! Thanks.

 

I drove the truck this morning to work (I usually take the bike, but rain is forecast). It drove well until I parked and sat for a few minutes, then the TRAC/VSC lights came on again. No CEL, but I loaded my Torque app anyway and see if any codes were present. Sure enough, code P0440 (Evaporative Emissions Control). Again, no CEL light but I cleared the code and the TRAC/VSC lights went out, which is the first time I've seen those cleared by clearing the CEL code. Tonight I plan on checking the catalytic converter using the temperature difference technique and see if that could also be posing a problem. Anyway, thought I'd share.

 

Your CEL light is blown. I have had that code and the CEL light comes on. That code is a pain and probably not your cat. More like the evap valve in the fuel tank but could be anywhere from engine to gas cap.

And yes, that code will show the TRAC/VSC lights and they go away when cleared.

Edit: When I get that code (I get it every so often now too) all three come on, not just the CEL.

 

Unless it just happened, the CEL light still works as I've recently had 440 and 446 pop up with the light, sometimes. I can test that later too simply by pulling a vacuum line or thus. It is possible to have a code and not have the indicator light up right away from my past experiences. But this IS the first time I've cleared a CEL code and the TRAC/VSC lights went out too. I did replace the gas cap o-ring recently as well, and like I mentioned some of the vacuum hoses under the hood. I'm just going to keep tracing down possibilities that lead to other problems based on the vehicle age and mileage, thus including the cat and also 02 sensors.

 

Well, that is weird. On my '02...the check engine light comes on for all codes so far (only had it for the evap codes and A/F exhaust sensor) but every time the other two lights come on also. And after clearing the code...they all go away.

I find it odd you would get the TRAC/VSC but not the CEL.

 

Everything about this TRAC/VSC issue is odd. LOL

 

Because I mentioned here, I took temperature readings on the upstream and downstream cat's in order to get a better diagnosis as to their proper operations. The upstream unit measured roughly (the thermo was jumpy) 325 at the inlet and 440 at the outlet. The downstream cat was 340/340. This tells me that the upstream one is functioning properly. I am questioning the downstream unit though, but no constant codes so I'll just leave it for now.

Back on topic, all is still good with the TRAC/VSC lights again too.

 

Not sure if one of your issues might be with the Torque app failing an initial connection. On the 4th gens this will happen, and only the TRAC/VSC lights will illuminate without the CEL. It has something to do with the can bus system protocols not being recognized. It's happened on my 03' a few times and the Zero Point Calibration cleared it on those occasions. Not sure if this is a problem for the 3rd gens, but just thought I'd throw it out there. Hopefully your problem is a simple fix.

 

Seemingly haven't had a problem with the CEL not showing, but I do see what your saying and it's probably intermittent. In fact, funny you mentioned it, this morning on the drive in the TRAC/VSC lights came on again followed shortly by the CEL. The code was P0440. As stated, I've already gone the fuel cap route. Guess I'll be diving deeper into the fuel system, maybe the canister and/or purge solenoid. I was able to clear all lights by clearing the code itself.

 

Mine started creating pressure again. I can hear a weak vacuum when I take the cap off now. Code hasn't come back either.

I priced up all the parts from the charcoal canister to the gas cap/filler to the gas tank and I think it came out to like $650 from an on-line TOYOTA discount dealer. If the light comes back and I have to drop the tank...I'm just doing the whole damn thing.

I did try a new gas cap and put dielectric grease around the filler tube end...but that was a while ago and the light came back twice more. Goofiest thing ever. I just want it to break and stay broken so I can find where to fix it.

 

I know this is an old post, but i had the same issue and everywhere I looked, I read similar posts to this one. In my 02 4R, I was experiencing the same phenomenon. It wasn't until I replaced the fuel tank vent valve did the issue get resolved. The cap had a hairline crack at the top that precluded pressure in the system. It also had a gas smell.