HELP!!! I just did the PADDO method of AHC fluid change today while wrapping up baselining a new to me 07 lx. 160k no documented AHC maintenance. Things went more or less fine but now AHC is inoperable!!! I turned the truck on the first time after the left side blead and it took about 2 min or so to go from l to n. Turned it back off to do the passenger side quick bleed and when I got back in the truck it would not go from l to n. Previous to this procedure AHC was working and I had 9 grads with just barely out of spec rear pressures and spot on front pressures. I am at a loss. The pump was initially louder than usual but now I can't hear it...
I'm getting this code:
C1751 - Continuous current to compressor motor
I've tried the "bleed air of AHC" aka "Active Test" in case it is suffering from air lock. I can hear the ?pump? motor running but the vehicle does not move. The ahc does not seem to respond to this procedure. The truck isn't moving when I try to force the pump on. After the "bleed air of AHC" procedure I am getting additional codes / lights:
C1762 - Abnormal Oil Pressure for Pump
and
AHC "off" flashing or staying lit
I'm happy to dig in techstream for some other data if it would help.
I also tried to re-bleed the height accumulator (the 12 inch cylinder on the driver frame rail) because when I first blead it I almost blead it dry and thought maybe I let some air in there and now that it is pressurized (per techstream the pressure there is 6.5)... I don't understand how this is the case but when I tried to re-bleed nothing came out...
I also manually activated the pump it does run! So what is the deal?
Next step I tested for Motor Relay Continuity... I get about 62 Ohms out of terminals 3 and 4 but my multimeter isn't beeping to indicate there is continuity... what does this mean??? is the relay bad??? terminals 1 and 2 are open and when a 12v load is applied to terminals 3 and 4 terminals 1 and 2 have continuity (with the beep from my multimeter). I swapped the ABS relay for the AHC relay also as a test but still no dice. I'd test the AHC Pressure sensor on the pump since that is the last thing to test in the flow chart for c1762 but I can't see how I would do this without taking it out of the truck and I'm worried I'm going to spill all my fluid if I take it out??? Will all the fluid leak out where the pressure sensor is??? I might just risk it to get to the bottom of this. The pump is definitely pumping but the suspension is going nowhere...
I checked the pressure sensor. I think??? its the one on the pump assembly right next to the temperature sensor right??? reason I'm not sure is the connector is three pins in a triangle orientation whereas the fsm shows them in a line... I am only getting .66 volts, should be getting 4.5 volts, I'm just not sure about my testing because the diagram shows 3 pins in a row but I have three pins in a triangle arrangement so I could be testing the wrong pins. Do I have the wrong sensor???
After messing with it all day I now have no pressure at the front or rear sensor... see second photo for current techstream data...
I'm getting this code:
C1751 - Continuous current to compressor motor
I've tried the "bleed air of AHC" aka "Active Test" in case it is suffering from air lock. I can hear the ?pump? motor running but the vehicle does not move. The ahc does not seem to respond to this procedure. The truck isn't moving when I try to force the pump on. After the "bleed air of AHC" procedure I am getting additional codes / lights:
C1762 - Abnormal Oil Pressure for Pump
and
AHC "off" flashing or staying lit
I'm happy to dig in techstream for some other data if it would help.
I also tried to re-bleed the height accumulator (the 12 inch cylinder on the driver frame rail) because when I first blead it I almost blead it dry and thought maybe I let some air in there and now that it is pressurized (per techstream the pressure there is 6.5)... I don't understand how this is the case but when I tried to re-bleed nothing came out...
I also manually activated the pump it does run! So what is the deal?
Next step I tested for Motor Relay Continuity... I get about 62 Ohms out of terminals 3 and 4 but my multimeter isn't beeping to indicate there is continuity... what does this mean??? is the relay bad??? terminals 1 and 2 are open and when a 12v load is applied to terminals 3 and 4 terminals 1 and 2 have continuity (with the beep from my multimeter). I swapped the ABS relay for the AHC relay also as a test but still no dice. I'd test the AHC Pressure sensor on the pump since that is the last thing to test in the flow chart for c1762 but I can't see how I would do this without taking it out of the truck and I'm worried I'm going to spill all my fluid if I take it out??? Will all the fluid leak out where the pressure sensor is??? I might just risk it to get to the bottom of this. The pump is definitely pumping but the suspension is going nowhere...
I checked the pressure sensor. I think??? its the one on the pump assembly right next to the temperature sensor right??? reason I'm not sure is the connector is three pins in a triangle orientation whereas the fsm shows them in a line... I am only getting .66 volts, should be getting 4.5 volts, I'm just not sure about my testing because the diagram shows 3 pins in a row but I have three pins in a triangle arrangement so I could be testing the wrong pins. Do I have the wrong sensor???
After messing with it all day I now have no pressure at the front or rear sensor... see second photo for current techstream data...
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