P0500 Code Vehicle Speed Sensor

My 2005 Prerunner V6 with auto transmission has the CEL on with a P0500 code. I cleared it once and the code came back within a couple of days. From what I can tell, this code means there is no SP1 vehicle speed signal when speed is indicated on SP2. Can anyone advise the source of the SP1 vehicle speed signal? Some things I've read online indicates the ABS wheel speed sensors. The ABS light is NOT on.

Also, note that the speedometer is working fine and the truck is driving fine. The only issue is the CEL.

 

I bought a WiFi OBDii scanner hoping it would be useful for troubleshooting. There is only one measurement for vehicle speed. It’s fine most of the time, but it was reading 0 in the freeze frame data that was recorded when the code was recorded. Does anyone know if this measurement is from vss 1 or 2? I think i was going about 20 leaving the work parking light when when the MIL came on. I didn’t see any glitch on the speedo.

 

I threw this code after I washed my engine bay

 

ABS/Skid codes can store and be current but don't always illuminate the ABS light. I see this lots of with rear ABS codes, Toyota doesn't trip the ABS light as easily in the earlier 2005 and 2006 models it seems.

You need to scan your ABS module for codes. Auto models use the wheel speed sensors for the speedo.

The VSS sensor 1 and 2 is only on manual transmission models.

The 2nd gen taco's are known for the rear ABS harness corroding.

 

Been dry here and couldn’t tell you the last time I cleaned the engine bay...

 

Thanks for the info. I’ll see if a local parts store will scan ABS codes for me.

Any chance mismatched tires could cause this? I’m overdue for a rotation. Maybe I’ll do that and check out the wheel speed sensors today.

 

No ABS codes

 

I tried monitoring the speed signal between the cluster and the ECC with a DMM (all I have at home). It’s at around 4.5 VDC. I saw that increase by ~.200VDC when driving up to 50 mph. It seems the cluster output is at least changing as a function of speed. This would point to the ECU, but that seems unlikely to me.

Both a friend that’s a Toyota tech and the parts counter guy at oreillys recommend swapping the sensor in the tranny, even tho the code is for sensor a. I reseated the connector on it. Maybe that will help. Contacts looked good

Measured resistance of tranny sensor and it was around 600 ohms. There’s a sensor that looks the same in the input end of the tranny. I measured it and it was about the same.

 

I borrowed an oscilloscope and finally caught the signal at a time when the light is on. The signal was usually swinging between 0 and ~4.5V. When the light came on, I captured the attached waveform. 0V is in the center of the screen. The signal is swinging between 4V and 4.25V.

I think the output driver on the gauge cluster has failed.

 

Has anyone tried opening up the combination meter to repair the circuit board? I am thinking that my problem is likely a broken solder joint.

I have been quoted around $600 for the local dealer to replace the combination meter. It turns out you can't buy a new cluster from Toyota and install it yourself.

 

After pulling the cluster to check the wiring, I dropped it off at the dealership today to get a new cluster put in.

Hoping this fixes it...

 

Hope it gets fixed, let us know

 

So far it seems to be fixed, but since it was intermittent, I’ll wait a few weeks to declare victory.

 

I had this code pop after a dirty/wet offroad trip. I unplugged all wheel ABS connectors, wiped out, and replugged and it worked for me.

Heres to hopin!

 

I have this same issue on my 2005, 4x4, Dbl Cab, TRD Sport (I'm the only owner)

I am getting a P0500 CEL and I have tested the speed sensors (skid control sensors) at both front wheels and replaced the speed sensor on the auto transmission and checked wiring and fuses so it appears to be in the instrument cluster or ECC. I am not going to pay some inexperienced Toyota mechanic to update the computer and then troubleshoot the issue for multiple hours just because Toyota does not want to acknowledge this is a known issue and give their mechanics a TSB.

Has anyone found a simple solution to this problem ie soldered a connection on the combination instrument cluster board? Side note: I had a problem with the overhead compass display and soldered it a couple of years ago and it still works great. Therefore, I would not be surprised if instrument cluster has a faulty solder connection.

Thanks in advance.

 

I am an electrical engineer that designs printed circuit boards for the aerospace industry. Based on the waveform I observed at the ECU input, I am confident that a broken solder joint was most likely the issue. I tried taking the cluster apart, but chickened out before I got to the front side of the PCB. I didn’t want to do something to corrupt the odometer reading.

Now that the cluster has been replaced, I may dig into the old one to see if I can find the problem with it.

 

Ncskeeter, thank you for your reply. I think you are on the right track. I have managed large non profit Data Center server farms (5K+) and this is a very common issue among servers that have run for a few years; I think solder weakens over time from vibrations and finally cracks.

 

Stresses from thermal cycles are more likely to cause solder joint cracks than vibration, especially in a low vibration environment like the cab. Mine spent many years in the Texas heat, which I think contributed.

From what I can tell, the VSS signal is pulled up to around 5 VDC inside the ECU. I think the output of the combo meter is what is known as “open collector” or “open drain.” It either pulls the signal hard to ground or looks like an open circuit, allowing the ECU to pull it high. If the circuit path inside the cluster has high resistance, then a resistor voltage divider would be formed between the ECU pull up. When the combo meter tries to pull the signal low. This would cause the voltage waveform to look like I observed.

I attached two waveforms, one normal and one when the failure happened. (Bottom is normal)

 

Update: replacing the cluster has resolved my issue.

 

Update: removed cluster and magnified every solder point and could not find any cracks. I ordered a rebuilt cluster which included a new circuit board from http://www.taninautoelectronix.com/ for $200 + $25 for shipping and this resolved the issue. It took about two weeks for them to build the cluster. Taking out the old cluster and installing the new one took about 20 minutes, only because I had never done it before. I am very happy. Thanks, Ncskeeter, for your help!