Changing the Actuator

Here is a thread where I put the voltage info for the ABS pump. The off trigger point is 4.7 volts and the pump start trigger is ~3.3 volts.

ABS Actuator - How often is too often? | PriusChat

 

Perhaps its air in the ABS modulator ? but i hear the pump with every brake pedal push. (on the last drive I did ) - Havent run TS since this last drive. behaving the same and I think there is an issue with AUX bat. not maintaining charge... have a 2A charger on it .. it is new as of the end oflast year .. it is not AGM .. it is LeFe ...
I presume there won't be any good voltages coming off the ABS until it is itself blead using techstream or similar functioning scantool.

 

just went for a longer test drive (actually over 5 min) -- glad to see I'm running in closed loop for the catalyst (o2 sensor back in position) --
When the brake pedal gets a certain way down .....I hear this chirping coming from back .. like when a pocket of air gets compressed ... maybe that's the cylinder with the high voltage (5v) being reported and in need of further bleeding ... LR or driverside back ...

 

there was a generous amount of air in that rear left cylinder .. however the voltage did not drop for that cylinder .. i cleared the FF and will be trying to read again and hopefully the V for RL will be down where it should be.
Got the latest FF and still RL wheel has near 5v ... not sure anything else changed ... accumulator sense reading 3.17v.
the Mityvac is a big asset ... relying on the accumulator to pump is not something to bank on but pulling vaccuum through the bleeder nut is a sure bet.

 

Finally got our mechanic to look at it .. he 's really bz and apparently had some last minute 'emergencies' ... incidentally trying to start the thing this am (was very foggy) - -got a couple of U-codes (communications) .. was able to limp the car there 5 miles .. he ran his fancy snap-on scantool .. did the ABS brake bleed operation .. then concluded problem not in bleeding/air in system .. or wheel cylinders .. that 5 v coming out of the RL wheel is a pressure sensor .. and since i didnt have that problem prior to replacing abs unit ' we concluded' the replacement abs unit must have the faulty sensor in it .. car stops but i have a condition (every so many starts) where its been sitting and i push the brake pedal to the floor and the 12v dies and i have to jump it to get it to come alive PS .. i tried to write about the U codes thi smorning and seems p.c. site server was down aalll day long...

 

was there a way to test it ? should i have plugged the 33 pin connector harness in after the $200+ labor time ?
Well .. there was the 'bleeding breaks with out turning it on' video .. so --
You would have to hook the actuator to a test harness which probably comes with an expensive unit like a snap-on scan tool or esp the toy test tool diagnostic ..

maybe someone can chime in on testing the actuator (yes I did print out the resistance checks .. a good preliminary that _WILL_GIVE a good idea that the pump motor is good .. then there was the resistances on the fine pins and the 'the 1st 2 measurements are wrong' .. this gave a very un-reassuring feeling ..

 

someone bought my old unit in miami and is taking it to south america .. i think its the pump that failed but it could be more ..
there is a utube of some asian guy taking the pump motor out and replacing the bearings ...

 

When performing the tests on those diagrams, 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.

Update to this: I took resistance readings from an actuator that was failing (runs every 20 seconds or so), and the readings were within specifications. I guess if it has bad O-rings or something inside it would not be reflected in the measure of electrical components within.