01 Sienna vibration

[Hotpursuit]

My 2001 Sienna XLE has a problem. The ABS and TPMS lights both come on after a few miles of interstate driving at 70-75 mph. I can detect an intermittent vibration in the gas pedal before the warning lights come on. The front brake rotors and pads have been replaced and the tires have been regularly rotated and balanced. The warning lights go out once the engine is shut off so there are no stored codes (I have a code reader). I have shifted the trans in neutral when the vibration occurs to see if it goes away but it still continues. The engine was tuned back in April (plugs, timing belt, etc) so I do not believe it is an engine misfire. The vibration goes away once the ABS & TPMS lights come on. Why would warning lights coming on cause a vibration to go away? It seems as if the computer disables something once the trouble lights are lit. Could it be a bad CV/axle that is causing a vibration which makes the ABS & TPMS systems think there is a problem?

[TrailDust]

I'd tend to agree that you may have a bad CV axle joint. The bummer is that you have to take the axle out and disassemble the joint to find out. You might try putting your car in neutral (if it's safe to do so given the immediate driving conditions) when the vibration is occurring, and if the vibration is still there it's probably the axle joints, and if not then it may be another source like the engine mounts, etc.

[Hotpursuit]

Apparently it is something with the ABS system. I jumpered the Tc and E1 terminals in the diagnostic port under the hood and it gave me code 32 (left front wheel sensor signal problem), code 33 (right rear wheel sensor signal problem), code 34 (left rear wheel sensor signal problem) and code 41 (abnormally low battery positive voltage). I suspect the problem is with ABS ECU or the ABS pump. How can I confirm which of these two it is? Or if it is not one of these two parts, what is the problem?

[Hotpursuit]

I took my Sienna to a local mechanic. He checked the reluctor rings and they were ok, as were the axles. He determined that it was the abs acuator and replaced it with a used one (new ones are $1200-$1800). When I picked it up he said it still had the problem but it was only showing code 33 (RR wheel sensor). He manually checked the RR sensor and it checked out as ok. I drove the van on vacation and it still has the same problem except for codes 34 and 41 are no longer showing up. Codes 32 (LF sensor) and 33 (RR sensor) are still present.

Any idea as to what I should check next?