I ordered a used ABS actuator and took some resistance readings from it. It scored well on the first 4 parts of this diagram, but on the last 2 parts I get 500 ohms exactly instead of "about 33 ohms". I saw another post here in which the person got the same 500 ohm readings on those connectors. I haven't removed my actuator yet to see what kind of readings it gives. It runs every 20 seconds or so and give a low pressure code...no dash malfunction lights yet though. Could someone please post some resistance readings from an actuator they have? It would be good to have some real world comparison data. This is the model #44510-47050
I found this old thread with a PDF document about the testing and install Changing the Actuator | PriusChat He states that he also measured 500 ohms on the pin1 to pin33 and pin2 to pin33 and found resistors inside that add up to 500 ohms. It is possible that the actuator was revised to include a greater resistance in order to reduce the noise it makes, and the documentation department didn't get the memo about it. The rest of the testing is not entirely clear, but if the pump works then it won't have to be removed again for a while.
When performing the tests on this diagram, you will get 0 ohms from pin 20 to pin 7 and same when measuring from pin 6 to 19, but if you measure from pin 6 to pin 7 or from pin 20 to 19 you will see reading that are within the 14.6 to 24.6 ohm range (if all is well with the actuator). It makes sense that since most of the other readings are pin 13 to pin 14, 27 to 28, 11 to 12 etc. that it would be 19 to 20 and 6 to 7. It just looks like a typo in the chart and behaves like one. This provides a basis for bench testing a salvage actuator pump if you don't have a new one to install. Whether or not this will fully diagnose the pump is another story. I measured 2 used pumps and got similar readings, and will test the noisy complaining one once its dislodged from its moorings deep in the engine room.
I'm under the impression that it's the accumulator which fails, causing the pump to work overtime. Do these tests address the accumulator or pump?
It's probably academic on a Gen 2 as they are both on the same assembly. The fix for either is to replace the entire assembly.
Those tests check for gross electrical failures in the actuator. Has nothing to do with how the hydraulic bits work- or don't. The accumulator stores high pressure brake fluid. If that leaks the the pump will run more often- only when you use the brakes, as it can store less fluid. If a valve inside the actuator leaks, then the pump will cycle on and off even if you never press the brake pedal. Posted via the PriusChat mobile app.
