2007 ECU diagram.

Hello all! Thanks for the add. 07 tundra, 205k.

Ok, here is my situation. I have 07, SR5 4.7 that is throwing a P0500. Took it to a friend that has Toyota software and we ran through the wheel sensors and gauges, all are working. Both speed sensors on trans are working too. My speedo works but it seems the signal out isn't there. Does anybody know how to test between the speedo and ECU without pulling the cluster? From my understanding, the signal is 5v square wave. So that should be 2.5v on a volt meter?? Is there a ECU pin diagram around?

 

This has the 2008 Sequoia which is 90%+ the same as Tundra.

https://www.car-inform.com/sequoia/

You can get individual items or all of them here:
Toyota Sequoia 2008 Repair Manual Download

 

Welcome from LA (Lower Alabama)! This thread has pretty much every wiring diagram for every Tundra through the '20's:
https://www.tundras.com/threads/ultimate-wiring-diagrams-collection.81448/

 

The ABS/Stability control ECU reads the 4 wheel sensors and creates the vehicle speed signal. It is broadcast on the CAN network to all the other ECUS, this is the signal that moves your speedometer needle on the cluster. I believe the two speed sensors in the transmission are only used to monitor shaft RPM in the front and rear of the trans for shifting ect.

However it seems the ABS ECU also has a SP1 out wire that goes through the cluster and then to several ECUs (Engine ECU, TPMS ECU, Radio). I believe this is the wire that tells these modules how fast the vehicle is traveling and might be the reason for your trouble code. Seems the assumption is the Engine ECU is not seeing the Speed signal so it throws a code. I am surprised the Engine ECU is not reading the speed on the CAN messages, it is seeing the same data the instrument cluster is.

What the signal is like on this wire, I am not sure but this seems to be what you are asking about.

I quickly pieced this together. Seems to me the Skid control ECUs the wheels sensors, sends the signal out on SP1(yellow), it comes into the Cluster on SI(grey) and then out on +S(purple) which gives a speed signal to TPMS Ecu, Radio, Sonar ECU and the Engine ECU on SPD(Black). At least that is my interpretation of the direction the signal is moving.

 

This page explains how the system works and pulses the signal pretty well. As I mentioned the Skid control ECU is creating the pulse signal, passing it to the cluster and the cluster sends it out to all the other ECUs. This is not the signal that runs your speedomater however, that is all driven by the CAN
https://www.ttguide.net/speed_signal_circuit-2093.html

 

Jeff, you're on the right track. From my understanding it takes all 6 sensors for the speedo to be functioning. Mine is. That's not the issue. The communication from the speedo out to SCECU is where I need help trouble shooting. I'm trying to avoid removing the cluster to do a continuity test from behind the cluster to SCECU. Would like to save that for last if all possible. I'm going to go see if there is any voltage on the SP1. If there is, does that mean its in the SCECU?

 

This line from the pdf above “To create this signal, 12 V is output from IG2, which is behind a resistor in the combination meter assembly. This voltage is sent to the skid control ECU. The pulse signal is created by switching the transistor in the skid control ECU on and off, making the voltage on the wire drop to 0 V.”

Makes me think you probably have voltage on the wire from the cluster to the Stability Control ecu (SP1) no matter what but you only get a signal when the Stability control ecu pulses back.

Of course if you have no voltage constantly that could mean the wire is broken or the cluster is faulty and not sending 12v down the line. (Or the signal is pulsing down to 0v so fast you are not picking up when it’s high)

If you do pickup a signal coming out on SP1 I think it’s safe to say it’s reaching the cluster, you would would have to check the S+ out of the cluster to see if it’s passing the signal on to the engine ECU.

Also I think the speedo gauge will work with only the 4 wheel speed sensors. The two speed sensors on the transmission only report back to the engine ecu. The speed gauge can be moved with only a CAN signal from the stability control ecu