VSC, TRAC light on

[Ventura HiWay]

Greetings,

2001 Highlander; Check engine light was on and along with it the VSC & Trac Off lights were on. I understand that when there is a engine code set the VSC & Traction Control is disabled. The engine problem has been corrected and the code cleared but I still have the VSC & Trac Off. Does anyone know how to clear / reset those lights?

Thanks

[Blue Bowtie]

Welcome Aboard!

Since no one else wants to take a stab at it, I'll give it a shot.

The ABS/Trac system runs a short self-diagnostic every time the ignition is turned on. As part of the normal self-diagnostic routine, the warning lamps will turn on or flash. If an error condition exists, a warning lamp will turn on and remain on. Try turning on the ignition WITHOUT starting the engine, and observe the lamps. If the ABS/Trac lamps turn off after a few seconds, the system should be operating normally. If the warning lamp remains ON, there is likely a system error and stored trouble code.

To display any stored trouble codes for the ABS system, you can jumper the #4 (Cg) and #13 (Tc) terminals of the Diagnostic Link Connector to make the ABS warning light strobe the sequence for the stored trouble code(s). Insert an appropriate jumper wire into the terminals, turn the ignition switch to ON without starting the engine, and be prepared to observe the instrument panel warning lamps.



The stored error codes will be displayed by successive 1/2-second flashes of the lamp, separated by various pauses between flashes. Each displayed code will be separated by a 2-3 second delay.

EXAMPLE: Stored trouble codes "11" and "23" would be displayed by a ½-second flash of the lamp, followed by a 1½ second pause, then another ½ second flash of the lamp (that would be a "1" and a "1", or code "11"). There would be a 2½-3 second pause to signal teh end of teh first error code sequence. There would then be a ½-second flash of the lamp, a ½-second pause, and another ½-second flash, a full 1½-second pause, a ½-second flash, a ½-second pause, another ½-second flash, another ½-second pause, and a third ½-second flash of the lamp, followed by a 2½-3 second pause (that would be two quick flashes, a pause, then three quick flashes, or a code "23").

When all codes are retrieved, turn the ignition switch to OFF.

Once you have successfully retrieved all stored trouble codes. you can clear the stored codes from memory. To clear codes, connect the jumper wire to the DLC again in the same terminals. Turn the ignition to ON without starting the engine. Depress the brake pedal at least 8 times within five seconds. Remove the jumper from the DLC ]before turning the ignition off, then turn off the ignition. All ABS/Traction Control codes should be cleared at that point.

If the system displays an error as soon as the ignition is turned ON again, it is likely because a fault condition still exists, and it is being detected as soon as the system performs its self-diagnostic on ignition power-up. The error codes are the best indication of where to look for system problems.

[Ventura HiWay]

Thanks for the reply Blue Bowtie. Good info. I was able to extract the code using the procedure you sent. I have a code 39 but I don't know where to find a reference for the codes. Seems to be a manufacturers secret. I would appreciate any other info you might have.

[Blue Bowtie]

Code 39 (P1239) - Foreign matter is attached to the tip of the left rear wheel speed sensor.

Well, DU-UH! the entire VEHICLE is foreign matter! Of course it's attached...

That's Toyota's explanation of the error code. In other words, the LR wheel sensor signal is weak or intermittent, but the sensor resistance is within specifications. The sensor is not consistently generating a sharply cut-off square wave output, or at least the ABS controller isn't receiving it.

In addition to the possibility of "junk" having accumulated on the LR sensor face (since the sensor is magnetic), the tone ring (toothed wheel) may also have rust or contaminants (like rust, road debris, undercoating or paint, etcetera) on its surface, impairing the ability of the sensor to generate a good signal from the inductive force of the tone wheel faces.

Pull the LR wheel and start looking at the sensor, tone ring, and connections, and I think you may find eventual joy with your ABS system.

[Blue Bowtie]

Actually, that's not entirely correct. The ODB-II protocol error code for that is not "P1239" but "C1239". I guess I got happy-fingers...

For reference, the same defined problem code for the RR sensor is Code 38 (C1238), for the LF is Code 36 (C1236), and for the RF is Code 35 (C1235). Someone down the road may find that useful.

[Ventura HiWay]

Pulled the left rear wheel, this past weekend, to inspect the sensor, tone ring, ect. Apparently the sensor & tone ring are an integral part of the wheel hub/bearing assembly and is not serviceable. (According to Haynes manual) I pulled it off anyway & removed the dust cover. Inspected, cleaned & reassembled with no success. I am guessing my next step will be to trace the wiring back to the ABS unit. If no problems are found it seems I have to replace the entire wheel hub/bearing assembly to service the sensor & components. Any thoughts?

Thanks for any input you might have

[Blue Bowtie]

The hub/ring/sensor assembly is supposed to be an integral assembly. The only way to service it is to press the bearing/shaft out of the hub and expose the tone wheel and sensor. If you don't have a press capable of that, you can still verify electrical connections at the wheel sensor and harness, and measure signal level directly at the wheel.

Since you've already cleaned the assembly as best you can without disassembly, about all you can do is test the sensor. The sensor is simply an inductive proximity switch with it's own excitation (magnet) in the case. The actual sensor element is merely an inductive coil which gets a current induced through it when the magnetic force lines are altered by the passing "teeth" of the tone wheel. The sensor coil has a design resistance of between 1,000-1,200 ohms, ± 2%. You can measure the resistance of the coil at the wheel hub to verify its integrity.

NOTE: Actually, the brake/traction control computer performs this check at every start-up, and if a sensor resistance problem were detected, the error code displayed would have been different. However, it's good practice to verify the sensor resistance anyway.

If the resistance is between about 975-1,280 ohms, it should be considered "good" and you can proceed. Make sure the ignition is OFF and connect an AC voltmeter to the speed sensor leads from the hub (or switch your already connected ohmmeter to read AC volts). Spin the wheel/hub at about 1 revolution per second (about 5-6 MPH). The AC voltage signal generated should be at or above 0.55VAC at that speed. You can compare the signals from the left and right rear wheel speed sensors for reference. If the signals are at a similar level, there may be a problem with the chassis wiring harness. You can plug the speed sensor back into the chassis harness and connect your AC voltmeter to the same leads at the brake/traction control computer, then measure the voltage to see if there is any signal loss.

NOTE: The ABS system actually monitors the frequency of the wheel speed sensor signal to determine wheel speed, but the signal must be of sufficient amplitude (voltage) to effectively signal the ABS computer. Therefore, measuring the voltage of the sensor output signal is a valid test of sensor performance.

If the LR wheel signal is weak when measured at the wheel hub, that is the likely cause of the problem. At that point, the best remedy in your situation would probably be to replace the hub assembly. Go for a "lifetime guaranteed" unit if you can find one so that any future problems will be someone else's responsibility. They're not cheap, at about $250 apiece, but the only other option is repairing the hub assembly yourself.

Good luck with the diagnosis. You've obviously got it narrowed down to one wheel, and likely one component. Before replacing it, however, diagnosing it is prudent, especially given the cost of replacement.

[k2rage101]

I have the same problem...my 2001 Highlander CEL came on, code was P1130 Air/Fuel Metering. I checked the air filter first, and it was filthy, so I replaced the air filter and cleared the code. CEL has stayed off ever since, but I still have the VSC and TRAC OFF lights.

Technically, the VSC and TRAC OFF come on with the key in the ON position, then go off. If I start the car and idle for an hour, they stay off. If I put the car in gear, forward or reverse, the VSC and TRAC OFF lights come on within 10 ft, but no CEL.

Does this mean I have a code stored, waiting to be retrieved? I didn't find anything stored in memory other than P1130, which has not come up again since I replaced the air filter.

[Ventura HiWay]

Welcome to AF k2rage102,

Actually my problem started the same way if I remember correctly. I had a CEL & the code had something to do with the air filter. Turns out there was a vacuum line disconnected. I corrected the problem, cleared the code & the CEL was happy. However I still had the VSC & TRAC OFF lights. Turns out I had another problem with the VSC. Check out the above posts from Blue Bowtie on how to retrieve & clear the codes for the VSC. Seems like I remember reading somewhere that when you get a CEL on Toyota system, it will disable the VSC. That may or may not be the case. The reason you can turn off the ignition, restart & everything appears fine until you move, is once you are moving, something is not getting a signal from the wheels to the control center. I suggest you start by retrieving the codes, clear the codes & see if it comes back. If so retrieve the codes again & start from there.

[k2rage101]

Ventura,

How did you finally get your VSC/TRAC OFF lights to clear? Your 2nd to last post suggests you tore the wheel apart, but were unable to fix any problem. Did you finally find out why you had no good signal from the tone ring?

I am currently suspicious of a wiring problem since my cabin dome light stopped coming on too. Then, it briefly came on one day, and has been back off since. I don't think the bulb is burned out, but IF the cabin light shares the same wiring harness as the wheel speed sensor, and this wiring harness is loose/disconnected, then maybe that is my problem. I have no idea where to look though at this point, and I am curious if/how you solved the problem.

[Ventura HiWay]

k2rage102,

Sadly I am ashamed to say that I haven’t got back to it yet. I have had other bigger fish to fry & limited free time. My wife drives it about 4 or 5 miles a day, so we have just been living with it for now. It is on the radar screen for the next month or so. I hope to have it repaired and I will post the results or inquire for more input if I run in to more obstacles. I will definitely post when I get it solved. This forum has been a great help to me so I want to report the results so others can benefit from the info.

I am suspecting that it is in that hub or a bad connection somewhere. Sorry I can’t tell you more at this time.

If you read the post above from Blue Bowtie, (the one with the drawing of the diagnostic link connector) you can follow those instructions to retrieve the codes & that will narrow your search. Also he explains how to clear the code. If you have cleared the code and it comes back as soon as the wheels start to move, it still has a problem. Most likely it is not getting a signal, or has a weak signal from one of the wheels. The code will direct you to the problem wheel or wheels.

Let me know what you find

Ventura HiWay

[newmanw10]

[FONT='Verdana','sans-serif']I have a similar problem. I took the car in for 60K service and they forgot to connect one of the hoses on the air filter (very common mistake). The CEL light came on and the VSC light came on. I fixed the hose and the CEL light cleared but the VSC is still coming on. Actually on start-up the VSC light clears but if I move at all in gear the VSC light comes back on. I took it back to where they serviced it and they said it is asking for calibration. Sorry but this doesn't seem like a coincidence as I never had this issue until they serviced the vehicle. Seems like they could have messed something up when rotating the tires or something. Anyone else have this issue and get it resolved.[/font]

[newmanw10]

I pulled the code, and guess what 39! Seems I have the same problem, something wrong with my left rear wheel sensor. Anyone have any success fixing this issue?

[newmanw10]

So what is left rear? Passenger rear or driver rear? I pulled bith sensors and they were all full of junk. BUT I am still getting the code? Bummer right!

[newmanw10]

Anyone know where the sensors are connected? I am wondering if a connection has been disconnected or is loose. Both rear wheel sensors are very clean now and the teeth underneath the sensor seem to be good as well. Could it be in one of the other wheels? Also this code is comming from the VCS light not the ABS light, could 39 mean something different coming from VCS light?

Hopefully someone has fixed this issue