P0500 code--Vehicle Speed Sensor

Hi folks. I'm new here and hoping someone can help me find the source of a problem with my 2005 Pre-Runner V6 auto.

A few months ago, my CEL illuminated. Diagnostic tool indicated P0500 (Vehicle Speed Sensor) was the culprit. After a couple restarts, the CEL cleared itself. Eventually, it came back on. This cycle continued for several weeks with the CEL staying on for longer and longer durations. Now, it stays on all the time.

There are no other symptoms. Shifting is unaffected, no ABS light, and the speedometer works fine. I checked the shop manual which led me to rule out the wheel and transmission speed sensors themselves (speedometer consistently works fine). I checked the connectors on the ECM and they seem to be solid as well.

Yesterday, I connected my OBDII tool, reset the CEL, and went for a drive around while watching the Speed graph from the tool. For the first 30 seconds or so, the speed registered just fine on the graph--then it went to zero. Again, the dash speedometer never faltered. After a few seconds, the CEL illuminated and logged the P0500 code

The only other guidance provided in the shop manual is that it could be a bad ECM. I can buy a salvaged ECM for around $150 but hate to spend that much without some additional evidence that it's the problem. I suppose I could just live with the CEL staying on, but it's annoying.

Before I go the ECM route, I thought I'd ask here if there's any other troubleshooting I could try.

Thanks,
Steve

 

If you have ruled out the sensors. You don't have to go directly from the sensors to the ECM. There are wires between them. Check the wiring and connectors between the sensors and the ECM.

 

VSS and ABS sensors work about the same.Dirt build up or other interference can happen abs sensors fail usually under 5 mph.I would pull sensor clean it and area around it.Hey my air bag sensor failed at 1800 miles.Shit happens keep us informed.good luck...

 

My 2015 prerunner has speed sensor on back of transmission and one on each of the rear wheels. I don't know for sure but the speedometer might be using rear sensors for speed signal when the trans sensor fails. A lot of new vehicles the computer will use other inputs to keep you motoring down the road, kinda of a fail safe. I think I would try changing the transmission speed sensor first, it would probably cost as must as the dealer to diagnose if your willing to gamble.

 

Thanks for the quick replies and suggestions. According to the shop manual, it's the wheel sensors that feed the dash cluster (speedometer) which is working fine. The dash cluster converts the speed signal and sends it to the ECM. That's why the manual says that if the speedometer is working fine, then the wheel sensors are ok. The manual doesn't indicate that the tranny speed sensor has anything to do with the P0500 code. However, I did remove them (there were two, one on either side of the tranny, both identical), cleaned them, and swapped them when I reinstalled. Same results.

I'm becoming more and more convinced that the ECM is the culprit. I guess I'll bite the bullet and try replacing it--or convince myself to live with the light on.

Again, really appreciate the responses. I'll post back if/when I ever figure it out.

 

Any update on this? I still have the P0500 error even after replacing the transmission sensor.

 

Yes! I FINALLY found the culprit. It was my speedometer cluster after all. It was receiving signals from the wheel sensors and displaying the speed just fine (that's why I originally eliminated the cluster as the problem). However, I ultimately discovered that it wasn't forwarding the signal to the ECM--a problem somewhere in the cluster circuit board. So, the ECM was receiving the speed signal from the tranny, but seeing zero from the speedometer--that caused it to throw the P0500.

So, if your speedometer appears to be working correctly (which means your wheel sensors are good) and your tranny sensors are good, it can only be one of 3 things: bad ECM, bad speedometer cluster (which was my problem), or the wiring between the cluster and the ECM.

If you determine that the cluster is the problem, you're in for a surprise trying to replace it yourself. I checked several Toyota dealers locally and on the net. None of them would sell me one through the parts department. The only option is to have the service department replace it--you're probably looking at around $500 for parts and labor. I wasn't going to pay that just to get the CEL to turn off. I finally found a salvaged one on the internet--paid $115 for it. However, because your miles are stored in the cluster, the odometer does not display the correct number. I took pictures of the before and after so I can prove the actual mileage to a buyer if/when I sell the truck.

If you determine that the problem is your ECM, let me know. I have a salvaged one (if yours is the same part #) that I'll sell you for $100 plus shipping. New ones are more than $1,000. Don't believe what you read on the internet--it has to be programmed to match your VIN, but you can do it yourself--no dealer required (takes about 45 minutes).

Let me know if you have any questions--I now feel like an expert on the 2005 Tacoma P0500 problem! I also have a shop manual so I can help you with instructions for replacing the cluster or ECM if you need them.

Hope this helps. Good luck!

Steve

 

Thanks Steve. Wow, it really does sound like you're the expert now. I forgot mention that I just completed an aftermarket headunit replacement. I'm thinking it's probably the wiring rather than your issue since there were other things I did like pulling wires/cables all over the cab. I'm going to test the voltage at the sensor harness and at the other end. What wires should I be looking for and where on the other end?

 

If your speedometer is showing your speed correctly, your problem is going to be between the cluster and the ECM. It isn't the wiring from the tranny sensor. The tranny sensor is "speed sensor B". The P0500 code is associated with "speed sensor A" which comes through the cluster.

I'll check the diagrams and reply with the wire colors that you're looking for between the cluster and the ECM. Might take me a couple hours to get back to you.

 

There is a large connector on the back of your speedometer cluster (combination meter). You'll want to test continuity (not voltage) from the violet-with-white-stripe (V-W) wire at connector position 19 to the V-W wire at the ECM (it passes through the #2 junction box immediately to the left of the ECM, but it's the same wire color all the way through). On the ECM, there are 5 connectors: E4, E5, E6, E7, E8. You want E7. The ECM is mounted vertically and I don't remember whether E4 is at the top or bottom, but here's how you can tell: imagine you rotated the ECM horizontally so the clips on the connectors are at the top--E7 will be the 4th from the left. Look for the V-W wire in position 8 (2nd row). You should have continuity from that point back to the cluster.

Let me know how it goes.

Here's the diagram:

 

Awesome, thanks for the info. I'll have to check this out. I also saw a TSB (http://www.autocodes.com/uploads/toyota/T-SB-0242-09.pdf) for the 2005/2006 Camry, 2005 Solara that is related to the P0500 error code. Apparently this requires an ECM re-calibration. I recall Toyota tends to use identical parts for some or all of their vehicles. I can only imagine how much this will cost since my truck is no longer under warranty.

On a side note, I'm also getting no speedo cluster lights when the rheostat harness is connected then they come on when plugged in. I wonder if the two are related since they both came about right after I replaced my HU.

 

Checked continuity from speedo cluster to ECM and it's good. Forgot to mention that I org replaced the transmission speed sensor with a non-OEM cheap part. Maybe I need to replace with an OEM part?

 

I had a similar problem also, my speedometer was not working, the CEL was on.. turned out to be the ABS computer.

Replaced it and worked well.

 

Thanks for the reply. My speedo is GTG. Everything seems to be fine except i'm getting the CEL which tells me something is wrong.

 

Adding to the weirdness, I fixed a few things with my HU install this weekend then tested continuity between the harnesses behind the speedo cluster and on the ECM. In order to test, I had to unplug these to test but after reinstalling the harnesses I still had the CEL. However, I was still parked so I am guessing that driving afterward closed the loop on the code. It was probably a loose wire or maybe even one of the harnesses.

 

Looks like I get to track this problem down now. Got the code and everything seems to be functioning just fine.

I recently replaced my front coils so I figured I ripped one of the speed sensor wires, but they tested fine so now I'm not sure what to think.

 

Were you able to figure it out?

 

I have the P0500 code too.
No speedo, no odo, no trip meter, CEL on as well as parking brake and ABS lights.
My wheel sensors are fine.
This started immediately after I replaced the alternator fuse

 

Ok so I have something similar. Mine has the ebrake and abs light on. Throws P0500 code...NO window controls and No blower control. Temp works fine can hear the control moving. Speedo now working. Feels like an ECM issue.

 

I had a faulty cabin fuse box. Replaced with one I pulled at a wrecker, then also had a short in one of the ABS wires.

Speed sensor was fine all along