02 ckengine, brake, abs, vsc trac indicators on

[Raptor88]

Just joined to ask about my son's 4Runner, though I've gotten much great info in the past from the toyotanation for our 02 Sienna.

His 4Runner is a 2002, 2 wheel drive, auto trans. It has the check engine, brake, abs, vsc trac, & vsc off indicators on solid. He said that his transmission also seemed to not be shifting right. Here's what we did so far:

1. Checked his auto trans oil with engine idling. Oil was extremely low, with the level ony about 1/4" up on the tip of the dip stick. He said he never checked the oil since he bought the 4Runner about 3 years ago. Couldn't believe it!. --- Added about 1.5 quarts of Dextron III oil to bring the level to full and he said there was a huge difference. But one time when an auto shift occurred, there was a momentary slipping and then the shift was OK.

2. Hooked up an OBD-II scanner and got a "P0500 01/03" code. The P0500 is a speed sensor error but I don't know what the 01/03 means.

3. Ohmed all 4 wheel speed sensors and the ohm readings were: LF=1720 ohms, RF=1749 ohms, LR=1418 ohms, RR=1381 ohms. Ohmed the auto trans speed sensor and it read 672 ohms.

4. Hooked up an oscilloscope to all 5 sensors, by disconnecting the connectors. So the o-scope was connected open circuit to each sensor. Every sensor showed wave patterns with no apparent missing pulses. The peak-to-peak readings were:
LF=.15 volts spinning tire by hand.
RF=.1 volts spinning tire by hand.
LR= .4 volts with both tires off ground and trans in drive.
RR= .33 volts with both tires off gnd and trans in drive.
Autotrans=.22 volts with both tires off gnd and trans in drive.

As I mentioned, every sensor showed wave patterns with no apparent missing pulses. So would it be safe to say that all 4 wheel speed sensors and the auto trans speed sensor are all good? And that the rings that the sensors are monitoring are all good too?

If all of the above is good, what's our next step?

Thanks,
Raptor88

[jetwhine]

Raptor88,

Well according to the book the best way to trouble shoot this issue is to check voltage at the ECM. It is located behind the glovebox. Pull the E12 connector from the ECM. Put shifter in neutral. Jack up one rear wheel. With the key on, have someone turn the wheel and read from pin sp1 to ground and see if you have a pulsing voltage of 4-6 volts. If not the book says that you would have a problem between the combo meter to the ECM, or the combo meter itself or the ECM. The flow path is from the wheel sensors to the ABS ECU to the combo meter to the ECM. I would think that you would need to check each wheel to verify that you have the 4-6 volts generated from each wheel sensor. It does not address the transmission sensor for this code of P0500
Although if your speedo is electric then a sensor would be involved. So if the combo meter was at fault then it could be the tranny sensor. Hope this is not too confusing.

[Raptor88]

Originally Posted by jetwhine

Raptor88,

Well according to the book the best way to trouble shoot this issue is to check voltage at the ECM. It is located behind the glovebox. Pull the E12 connector from the ECM. Put shifter in neutral. Jack up one rear wheel. With the key on, have someone turn the wheel and read from pin sp1 to ground and see if you have a pulsing voltage of 4-6 volts. If not the book says that you would have a problem between the combo meter to the ECM, or the combo meter itself or the ECM. The flow path is from the wheel sensors to the ABS ECU to the combo meter to the ECM. I would think that you would need to check each wheel to verify that you have the 4-6 volts generated from each wheel sensor. It does not address the transmission sensor for this code of P0500
Although if your speedo is electric then a sensor would be involved. So if the combo meter was at fault then it could be the tranny sensor. Hope this is not too confusing.

Jetwhine,

Thanks for confirming where the ECM is located. Understand what you said and will proceed with those steps. Might be a few days before we can work on his car again.

Thanks for the input,
Raptor88