2005 AC Condenser Replacement

FWIW here is what I ended up doing in case it helps someone else. I realize there are probably a lot of corners cut here, but my goal was to get the AC back in operation on a limited budget after damage to the condenser. This is the first time I have worked on an AC system.

- did a whole lot of reading on PC
- purchased replacement condenser w/drier assembly from ebay, ~$75
- purchased dual gauge manifold and venturi vacuum pump from harbor freight, ~$65
- purchased 7oz bottle hybrid AC compressor oil, 2x12oz R-134a with no additives, import/toyota AC o-ring kit from NAPA local, ~$50
- purchased mini-VCI from Amazon, ~$28
- purchased two day subscription to Toyota TIS, $15

Total parts, tools & materials: ~$250

- Used mini-VCI / techstream to pull codes from AC controller, B1423 pressure switch indicating low/no refrigerant pressure and B1421 solar circuit (may be due to dark/shade or could be a real issue)
- Following diagnostic procedure in TIS, disconnected pressure switch connector and shorted pins 1/4 to clear fault condition
- Briefly started up AC compressor to verify it was still operational- Shutdown AC and vehicle
- re-connected pressure switch
- Jacked up front end onto jack stands for easier front end access.
- Following TIS repair manual:
- partially removed left and right fender liners
- removed front bumper cover
- removed inverter bracket
- partially removed radiator top brace, lifted up out of the way w/o disconnecting hood release (this step seemed to be missing in the TIS manual)
- removed radiator top supports (not accessible without above step)
- disconnected upper and lower refrigerant line from condenser and taped over
- removed bad condenser
- attempted to assess amount of oil retained in condenser, but lost most of it when disconnecting lines. What remained looked clear and clean, though yellow/green presumably due to previously used dye?
- installed new condenser
- used childrens medicine syringe to inject ~2.5oz of oil into condenser upper port (TIS recommends 1.4oz, added ~1 oz extra to account for losses due to leak)
- replaced o-rings on both AC lines, lubricated with hybrid oil and re-connected
- re-installed various brackets and braces securing condenser / radiator
- attached manifold gauge to hi/lo ports with all valves closed
- connected vacuum pump to supply line and opened all valves
- pulled vacuum to -0.75 bar on low side gauge (had to cycle many times through closing manifold valves/disconnecting vacuum pump from small compressor to allow it to recover pressure, then re-connecting pump to compressor and opening valves to continue pumping down)
- system left at this vacuum with gauges attached overnight, no difference in pressure noted in morning
- tapped first R-134a can
- with manifold valves closed and system still under vacuum, connected can/tap to supply line
- powered vehicle on to ready, AC off, connected techstream to monitor AC data list
- opened can valve and manifold lo valve to begin charging, can went cold almost immediately
- noted DTC B1423 cleared a few minutes into charging
- about half way through first can turned on AC max cold / hi doors open, noted building hi side pressure and frothing in the sight glass
- Techstream reporting compressor running at ~6200 rpm
- first can went warm at about 15/100 psi, though it seemed to have a small amount of refrigerant left
- tapped second can, closed manifold and can valves, connected to supply line, re-opened lo manifold valve
- can did not get cold, no additional increase in pressure noted
- closed manifold valve, shutdown vehicle left overnight with manifold still attached
- next morning restarted vehicle, techstream and AC, pressures same as before 15/100 psi
- opened can valve and lo manifold valve, can went cold and pressure resumed increasing
- noted techstream reported compressor rpm was falling to ~4500 rpm
- used techstream active test mode to manually set compressor target rpm to 6400 rpm
- site glass went clear at about 200 psi hi side pressure
- closed lo manifold valve and can valve when pressures reached about 25/215 psi, 36.5 degrees reported by techstream at evaporator, 39.5 degrees measured at vent, ambient temps around 80 degrees / 25% RH as reported by techstream
- returned AC compressor to automatic control, rpms/target fell to 3600, 39.7 degrees reported at evaporator, 43 degrees measured at vent, site glass still clear
- re-assembled rest of front end

Of course its been unusually cool since then, after being in the mid-high 90s the week before but so far so good. AC seems to get cold pretty quickly and stay cold. We'll see what happens when it gets hotter

Rob

 

From what I've seen the b1421 can be ignored. The b1423 seems to be your problem, as this will cut power to the compressor to protect it if the refrigerant charge is low. It sounds like either your charge is very low, or the pressure sensor is failing. If you know the charge is ok, you can test by shorting the sensor to verify that it is the problem. There is a procedure in the TIS manual for that. Bear in mind that if it really is that your charge is low, or if something else is happening to cause the pressure to drop while driving, its possible that running without the pressure sensor could damage the compressor.

If charge is fine and you still get the same result with the sensor shorted I would guess that a problem in either the wiring or the AC amplifier itself could also produce this symptom.

Good luck!

Rob