Bought an $800 XC90 - is it worth fixing? Could be fun

[800DollarXC90]

On April 11, 2020, I purchased a 2004 Volvo XC90 AWD 2.9 B6294T (T6) as-is for $900 after dealership fees. The XC90 was a former auction car. There were some electrical issues I noticed during my test drive, but the car was in great condition given the price. I decided to purchase, have my mechanic inspect, and it's been my daily driver since. To date, the only work I've put into the car is an oil change, a new engine filter, and a new set of windshield wipers.

Here's a list of the car's issues I was aware of before purchasing:

Messages:

• TIME FOR REGULAR MAINTENANCE
  
  ANTI-SKID SERVICE REQUIRED
  
  BULB FAILURE MULTIPLE BULBS
  
  ENGINE SYSTEM SERVICE REQUIRED
  
  TRANSMISSION SERVICE REQUIRED
  
  BRAKE FAILURE STOP SAFELY

Dash lights on:

• ABS
  
  BRAKE
  
  CHECK ENGINE
  
  Red triangle with exclamation in the center of dash
  
  BRAKE FAILURE STOP SAFELY

[*]After a few minutes of driving, a message reading "BRAKE FAILURE STOP SAFELY" appears, and the temperature, RPM , and speedometer gauges die. The odometer stops rolling as well. When this happens, acceleration power goes in and out, the car jitters and glitches, and the transmission shifts rough for a few seconds, then driving is back to normal. However, the dash doesn't start working again - BRAKE FAILURE STOP SAFELY never goes away, and the aforementioned guages do not come back on. Note: I've driven a couple thousand miles since purchasing in March, and the odometer has only tracked >100.

Other issues:

• Driver window doesn't roll down
  
  Driver door doesn't lock
  
  Driver side mirror doesn't adjust
  
  Seat warmers don't work
  
  Entertainment screen doesn't turn on, but radio stations, volume, and buttons work.
  
  Stereo speakers pop whenever the radio is turned on.
  
  AC/Heat don't blow very hard, and AC isn't cold unless I drive fast. Smells weird.
  
  Gas tank sometimes locks, sometimes doesn't. Always unlocks.
  
  The "W" button doesn't seem to work.
  
  Cruise Control doesn't work after "BRAKE FAILURE STOP SAFELY" comes up.
  
  Sunroof shade won't move, is stuck open.
  
  Sunroof makes a very loud grunting/crackling noise when I open it.
  
  Sometimes oil pressure light comes on, then goes off after I restart.
  
  Sometimes "COOLANT LOW STOP ENGINE" comes on, I'm thinking there's a leak.
  
  Trunk battery, and battery area, is extremely corroded, but have never had problems.

My mechanic checked the car out for me. Told me it's a great daily driver, but keep it in a 50-mile radius from home. Of course, I've taken it on a couple road trips already. Car doesn't die ever, but I need to start looking into these issues before more arise. My mechanic also recommends I see a Volvo electrician by the end of summer to look at my computer system - but I'm not quite sure if that means I need the system replaced or refreshed. Here are a list of codes my mechanic wrote down for me. Some of the descriptions may be misspelled or way off as I try and decipher his handwriting.

Engine:

• 9282 - Control Module Problem
  
  E000 - Control Mode Comm
  
  9400 - Brake Pedal Sensor
  
  2910 - F. Heated 02 B2
  
  720A - Immobilizer
  
  261A - Long Term Fuel Trim
  
  4024 - Leak Dia Init Tank (Pump)
  
  4007 - EVAP
  
  E003 - Configuration Fault

Transmission: (Note: YOUR SENSOR)

• 0092 - Solaroid Park / Natural Position Switch
  
  E000 - Control module
  
  E003 - Configuration Fault

ABS:

• 0094 - Comm
  
  0100 - Comm
  
  0114 - Comm
  
  0100 - Comm

SRS:

• E003 - Comm
  
  00D5

His Notes of the car's general issues:

• Caster/Cluster(?) Purg Valve
  
  02 Sensor B25
  
  Leak Diag(?) Unit in tank
  
  Brake Pedal Sensor
  
  Trans Control Module
  
  Diff El Module
  
  Central EL Module
  
  Your Pote/Date(?) Sensor
  
  R.F axel seal
  
  Rear Brakes
  
  L.F. Axel
  
  F. Tires
  
  L.F. Door Module
  
  Motor mounts
  
  Front struts
  
  Front links (?)

I'm not sure what these codes mean. Does a code mean it can be refreshed, or does this mean a part needs to be replaced?

Anyway, I'm a total dummy with cars, but am hoping to learn some stuff along the way as I fix up this guy. I'm not exactly sure of where I should start, though. Any tips? What do you think of this list? Thanks so much!

[SuperHerman]

Always start with no parts required repairs. For you - start with your CEM. Look up water egress issues as some of your problems may be connection issues caused by water intrusion.

Also check the yaw sensor under the front passenger seat for water intrusion.

Check all of your vacuum hoses and plastic tubing for leaks, cracks, clamps or rotted rubber tubes.

There is also an on board diagnostic built into the car which will tell you what systems are not communicating - with this information you can back track and make sure your connections are not damaged. Do some searching and you will find a video and write ups on this feature.

Check your fluid levels: oil, transmission, brake and power steering.

Those are the free items.

The XC90 is not known for electrical issues unless something went wrong - like water intrusion.

[gregdianec]

Key sticks in ign. at shut down, sometimes trans sticks in park at start. Can sometimes pumping brakes will release this.

[gregdianec]

Help

[xHeart]

Key sticks in ign. at shut down, sometimes trans sticks in park at start. Can sometimes pumping brakes will release this.

Could be the Ignition Lock Cylinder issue. More here https://www.matthewsvolvosite.com/forum ... 72#p351472

[eapowers64]

You need to sign up to receive alerts from a local/regional pull-a-part or other self-service junkyard. The 04-06 six cylinder is notable for it's overmatched transmission. Thus, you get a lot of decent cars showing up in junkyards because of bad transmissions that would require costly repair. I bought an 04 for $750 and have replaced every audio component, seats, lots of interior bits, etc from a continual supply of junked cars. You also get to experiment on how to disassemble on a car other than your own.