Electronic Woes (I believe)

1st time Tundra owner as of 3 months ago. My 07 with 5.7L needed a new rear axle bearing and since this job can be a real PIA I opted to replace the axle/hub bearing and shield assembly with a NAPA aftermarket assembly. Everything went well but afterwards my ABS, VSC and 4Hi-4Lo lights were flashing and truck doing some very weird things on the road. Starts out well until I have to make a sharp left turn. After that the engine seems to cut out and I hear a bunch of noise coming from the engine compartment, yet it still idles, and it doesn't respond at all to any pressure you put on the gas pedal not even all the way to the floor. I come to a complete stop then the gas pedal is responsive for about 2 seconds and repeat the same scenario over and over and over again. After about 10 minutes of this it will clear itself up and away I go until the next sharp left turn. I am totally baffled with this, never experienced anything even remotely close to this in the 47 yrs I've been driving. I got all the lights to stop flashing by doing a zero point calibration but the other weird stuff persists.
Does anyone have an idea of what may be causing this?

 

Maybe a bad yaw sensor?

 

That makes sense with the triggering event being a sharp left turn. Do you know what a bad yaw sensor would do in regards to engine performance or throttle activity?

 

Not exactly, but Is the check engine light on? Have a code reader? My guess is that it could tell the brain to cut throttle until the certain conditions return. Maybe grab a used one from salvage just to tinker without it becoming too spendy unless you have time to dig deeper. I simply don't have too much time to get in a rabbit hole right now. Good luck!

 

Unfortunately no check engine light as of yet. I do have a code reader, just waiting for a check engine light to latch on to. Until then I am totally lost. Thank you just the same.

 

I can tell you the yaw sensor will trigger your abs and traction control which is probably some or all of the sounds you are hearing coming from the engine bay.

 

@Jeff_5_7 might be able to help.

 

I would be focused on what recently changed to "start the problem". You mention work on the real axle and my first thought here is wheel speed sensors.

The truck has a wheel speed sensors on all four wheels. It counts the teeth or pulses of the tone ring as the wheel spins to determine wheel rotation speed. This data is also then used to derive the vehicle speed in Mph to run the gauge on the instrument cluster.

All four wheel speed sensors report data to the ABS ecu (Toyota call its the skid control ecu) matter of fact this is some of the most important data coming into that ecu. The abs ecu controls, well abs, but also traction control (which cuts engine throttle) ect. It does this by monitoring and comparing wheel speeds, that's how it knows you may be loosing traction one or both rear wheels spinning much faster than front.

If you think about a sharp turn, the inside wheel of the turn travels a shorter distance than the outside, meaning less rotations on the inside wheels. Think about the arc shape tracking the wheels as you go through the turn, because of the width of the vehicle the outside actually travels a further distance.

Anyway I would be looking at wheel speed sensors on all 4 wheels, verify wiring is good and that they are all sending good data into the ecu. The fact this only happens in a turn and that it is throwing all the warning indicators controlled by the abs ecu really makes me lean toward wheel speed sensors, maybe more specifically the ones in the rear since that is where the work was just done.

I would be using Techstream and the data monitor in the abs ecu to watch the wheel speed sensor data in real time as you drive the truck. Look for weird or erratic data from one of the sensors especially when you make a sharp left turn. Techstream or a good scanner that can read abs trouble codes may tell you there is a problem or no signal from one of the sensors. Are they plugged in, was the wiring damaged? Its pretty fragile.

This would be where I would at least start and go from there depending on what you find.

Quick reference picture to kind of show the wiring on the rear axle for the wheel speed sensors. A visual inspection of this area on both sides would be my first step.

 

Thank you, Jeff. That makes more sense than anything I've read about or looked at yet. I know I didn't damage the sensor when I removed it from the original hub but I did screw up and unplugged it before disconnecting the negative battery cable, dumb move. Not sure if that would damage it. But you are correct in the wires are rather small. I will look at that much closer now. As for the Techstream, I don't have a clue what that is. If I don't find anything with the wires, perhaps I should just install a new sensor and splice in a new pigtail with plug.

 

I wouldn’t worry much about unplugging it with the battery hooked up, shouldn’t hurt the sensor.

I would verify it got plugged back in good and the correct way however. Also make sure it is fully seated in screwed in. A big air gap between the end of the sensor and tone ring is not good. Since your hub is new I assume there is no concern about dirt or debris inside the hub interfering with the sensor.

Techstream is Toyotas diagnostic software you run on a pc. It can talk to the truck and provide real time data. Very powerful

 

I just took the tire off, pulled the sensor out and there was a significant amount of white lithium grease on it from the new bearing. So I pulled the assembly off, cleaned out all the excess grease and wiped the sensor off really well. The plug end of the wire is made in such a way it can't be plugged in wrong. I checked the wires and didn't find anything suspect, then put it all back together. Took it for a spin and now I don't even have to take a sharp left turn to trigger the same thing. I took a right out of my gravel driveway and once she was running straight I pressed on the gas enough to spin the wet sand and gravel off the tread and got my just reward, the total loss of power and the CSV light flashing. Still took it about 1/4 mile down the road, turned around and back home. It took me almost 15 minutes to go that distance.

 

Well I think you definitely have a wheel speed sensor issue, the question is why.

Did the hub seem like it was full of grease?

As you know the sensors screws in there and counts teeth on a gear. It needs no obstructions between it and the teeth.

I wounded if a trouble code was thrown in the abs when you unplugged the sensor. The Trac vsc lights in generally mean it has codes in it.

Try to clear them? Unhook the battery for the night… maybe

 

Did the Napa hub bearing unit include the wheel speed sensor? If yes, try swapping with your original one if it’s not seized into the bore.

Are you 100% sure you installed the correct bearing unit? A RH on the LH side, or vice versa will make the wheel speed sensor read in the wrong direction. Yes, they read forward or reverse direction off the poles of the magnetic tone ring built into the bearing.

 

Oh, and if you need to get somewhere, leave that sensor unplugged. You’ll have an ABS light staying on, but you should be able to drive it that way with no ABS or traction control. Do so with caution.

 

The new hub was most definitely overfull with white lithium grease. I cleaned out a fairly large amount after traveling just 50+ miles. Hopefully all the extra grease has already leaked out. I still have some noise coming from the rear end, so I'm left wondering if maybe I replaced the left axle bearing when it should have been the right axle bearing. No sloppy movement in either side, very tight like they should be. Still baffled as hell, never had to deal with anything like this. I'm thinking, did I make a mistake buying a Tundra? Been a Mopar man my entire life.

 

Yup, if the assembly was for the right side the brake caliper assembly would have been on the opposite side and would have been very difficult at best to mount. No sensor included on the new assembly.

 

If one side had a loose/worn bearing the other side probably isn't far off from being due. Sensor to tone ring clearances are close, not much wiggle room.

 

Hmm, now there's a thought worth considering for the short term. I drove for many years before abs was ever dreamed of, should not pose a problem driving without it again. Lol

 

Oh sheesh, it really was an assembly they sold you. I suppose it even included the axle shaft?

At this point, the easiest way to solve it is using a scan tool that reads ABS and will display live data. Reading the fault codes, along with monitoring the 4 wheel speed signals while driving slowly to show the odd one out, and if it’s showing the direction reversed. I suspect that bearing in your new assembly has a faulty or incorrect tone ring, but one needs more than guesses and suspicions to get it right.

 

Yes, axle included in the assembly. The only thing that didn't come with the new assembly is abs sensor and the brake caliper with mounting bracket. My ancient OBDII code reader isn't picking anything up, probably because there hasn't been a check engine light at all. I ordered a new one earlier this week and it will be delivered this Saturday. Hopefully it will be technically advanced enough to read the ABS/CSV/Traction control faults.

 

Neither side had a loose bearing, but the left side was moaning and groaning going down the road. Now with the new assembly on the left side the moaning and groaning has been reduced to a mere groaning, which is sounding like the right side. What are the chances though that the side I haven't taken apart would suddenly start throwing faults at the precise time I worked on the opposite side. And these assemblies aren't cheap. The left side was $900, for whatever reason the right side is only $550.

 

What happens if I just pull the fuse out for the ABS, would this cause other problems with CSV or traction control and result in the same loss of power I am currently experiencing? I think I will test this today, not that I will leave it that way if it does work, but to enable me to use the truck while still trying to find the source of the problem.

 

Just like I said, both sides were worn out and you only replaced one side. The distance between the sensor tip and the tone ring is critical for it to read correctly. You don't have to buy whole assemblies either. No need to unplug any sensors and leave wires hanging, just remove ABS fuse.Good luck!

 

Exactly what I was busy typing. Will work, but be warned, might could be used against you in a crash.

 

This image is on 100s of posts, but check the ABS fuse in addition to obstructed wheel speed sensors.

 

I think if I were to do anything I would unplug the wheel speed sensors one by one to see if it gets better or worse. Taking the abs fuse out may be a little extreme. The ABS ecu is one of the more important ones in the truck. You would definitely no longer have a speedometer or speed signal to any part of the truck. Could create more problems with trying to shift the transmission or other things. I personally would not be removing the fuse.

The trouble codes are another issue. Most code readers read generic trouble codes stored in the ECM only. Every ecu in the truck has the ability to stores it own trouble code for its corresponding system but most code readers don’t know the specific Toyota protocol to talk with all of these ECUs.

Toyotas Techstream is by far the best option just hard to get a hold of.

My opinion of the second best option is an IPhone app and wireless dongle that plugs into the OBD2 port. The app ObdFusion knows most of the Toyota coding. It’s $10-$15 to buy and another $15 for the enhanced Toyota diagnostic purchase in app to enable the specific Toyota programming. This gives you a lot of the functionality of Techstream right from the phone. Pair it with one of these

$28 Veepeak OBDCheck BLE Bluetooth OBD II Scanner Car Check Engine Light Code Reader, Auto Dual Mode Bluetooth Diagnostic Scan Tool for iOS & Android

https://www.amazon.com/Veepeak-OBDC...g7Fx6mzTMKYSdCXeL52r9Aja0vLfqQmhoCnv4QAvD_BwE and you are in business.

Ford around $50 you can have similar Techstream functions. Able to read and clear codes from all ECUs and you would be able to monitor wheels speed sensor data in real time from the phone display in app.

 

True, don't have to buy whole assemblies but after pricing the individual parts, bearing hub assembly and dust shield, it only makes sense to go with complete assembly. Bearing hub assembly is $230 and new dust shield, which is only available through Toyota, is $450. The previous owner of this truck cut away the majority of the original dust shield on both sides, probably because the were rusty and rubbing on the rotor or something. Then the price of having a machine shop press the old bearing hub assembly off and new one on is $75. Right side assembly from NAPA is $530, oddly enough the left side was $899 before taxes. Don't know why such a big difference in price though.
I will pull the fuse today to see if that will enable me to drive the truck while still trying to find the source of the problem. Thank you!

 

So I pulled the 2 abs fuses and she's back to running like a champ, just no speedometer. I will replace the right side bearing hub assembly and hopefully that will do the trick. The right side needs replaced anyway. With any luck that is all she needs to be whole again.

 

Report back with the results so maybe the next guy can have a little headstart. TIA!

 

Will do.