P0073 Ambient Air Temp Sensor Issue 2010 Volvo XC60 - UPDATE FIXED

aaronlife · Post by **aaronlife** » 11 Jul 2023, 11:36

Hi,

Hit a brick wall with this issue. The ambient air sensor started reading -40F the other day, or ---F, or it will start in the mid 60s (even if outside temp is higher) and start falling upon starting the car until it reaches ---F or -40F. If I'm lucky, the car starts up and it's around 60 and my AC kicks on. If it's one of the times it starts at ---F or -40F I don't get AC, which is a bummer, especially on hot, humid days.

I have replaced the sensor in the driver's mirror and there was no change in behavior. I checked the wiring connector between the door and the body and aside from some moisture around the outside under the grommet, it appears clean. I took off the inside door panel and checked the green connector from the mirror wiring, and that appears clean. I pulled back the rubber wiring cover between the door and body and removed the zip tie and factory electrical tape and the wires appear ok.

Any other ideas? Considering asking the local indy volvo mechanic, as the dealer I'm sure will want to start at the sensor per their instruction booklet for the P0073 (and to check my work).

Anyone know which pins and/or wire colors I am looking for to and from the connectors? the wires are a light gray inside the mirror.
Is there any way to bypass the sensor so I can get AC - setting on manual and LO on the dash controls does not work unless the ambient sensor reads 60F or above.

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aaronlife · Post by **aaronlife** » 11 Jul 2023, 11:46

Update, someone just shared this with me on another site. Will attempt to trace and check this... black and white wires...

aaronlife · Post by **aaronlife** » 11 Jul 2023, 12:57

Does anyone know where I would find 74/301? I could not figure it out from the diagram...

I was able to test the connector on the body at 17/18 and got about 4.8 volts (so I think the wires to the door are fine). I am assuming the ECM sends that voltage to the sensor and depending on the temperature, resistance varies, which effects voltage reading at the ECM??

I could not reach my tester ends to 17/18 on the door connector pins, angle was off, I would have to figure out something else, but I checked resistance inside the door on the green connector (2 light brown wires) that mate to the white/white black wires that run to the door, and I got 120K ohms. It's a warm day, 80F, car probably hotter than that in sun.

aaronlife · Post by **aaronlife** » 11 Jul 2023, 18:10

Fixed, I finally found several wires were cut in the mirror housing where it pivots when opening and closing during locking. I spliced in new wires underneath the BLIS camera and restored connectivity.

Only issues now are: SRS service warning light is on (presumably from the door connectors being unplugged with car on), I can't open the car door from the inside, and the door lock post doesn't go up and down properly with locking and unlocking, so I clearly messed up putting the panel back on.

Any advice on those issues is greatly appreciated. Thanks for anyone who replies.