2011 Tacoma 6 cyl automatic 4wd with 145,000 miles I replaced the ABS unit with a used one. I have checked all connections but all 3 lights (ABS, break, traction control) stay on, my scan tool shows no codes. I had a friend who is a mechanic check with his snap on scanner and he had no codes either. I have bled the breaks both manually and with scan tool to bleed the ABS unit. Truck is driving and breaking normally but I'm not sure if the ABS unit is working. I don't know where to go from here any help would be appreciated.
I don’t know if this will be specific to the Tacoma. Or even if the Tacoma and the Prius share similar braking systems.
The Prius of that same generation had a defective brake booster pump. (I don’t know the technical name). The pump would constantly run at idle, you could hear it pumping up. And it might even constantly run while driving too, it just would be hard to hear.
The reason it ran constantly was because there was some sort of small leak in the assembly, which would leave it dry. So it had to constantly run the pump. It didn’t leak to the ground, it just leaked inside itself.
Just throwing out an idea. Not sure if it applies specifically to the Tacoma. With that said, it is relatively easy to test for, you would hear the pump running constantly, if it is indeed the case.
@Kaizen Do you mean the vacuum pump for the brakes? If so, I doubt the Tacoma has the same system, since they are ICE trucks. To the best of my knowledge, the Prius (and other electric /hybrid cars in general) have electrically driven vacuum pumps to provide braking when the engine is not operating. If they have a vacuum leak somewhere then the pump would always be running to compensate for the leak.
For the Tacoma, could you not drive out to a rural stretch of road and make sure no one is behind you, drive up to 30-40mph and slam on the brakes to check if ABS is working?
Yeah, it’s probably the vacuum pump. GTK.