About 3 months ago my wife and I bought a used 2007 Honda CR-V LX 4 wheel drive. Last week on my way to work, I noticed that the green D on the transmission gear indicator was blinking but that the MIL (check engine light) was not illuminated. The owners manual states that this indicates a possible issue with the transmission and you should take the car to a dealer. The car currently has about 46k miles on it. We are the second owners.
That afternoon, I took the car to a local Honda dealer to have them pull the codes out of the PCM (powertrain computer module) and diagnose what the issue was. During that time, I did some research online and found that about 90% (my rough guess based on Google results of my searches) of the time when the green D is blinking, the 3rd gear pressure switch has failed and needs to be replaced. Regardless of if the problem was with Acura cars, Honda Elements, Honda Pilots, or Honda CR-Vs, it almost always was remedied with a new 3rd gear pressure switch.
The dealer charged me $96 (plus tax) for the diagnosis. I was told that transmission sensors and switches are not covered by the powertrain warranty but by the new car bumper to bumper warranty that expires at 3 years or 36k miles.
The code pulled from the PCM was P0847. The code indicates that the 3rd gear pressure switch is not operating correctly. The shop manual shows quite a procedure to determine if the switch is faulty, if there's a true problem with the transmission, or if the PCM is faulty. The dealer determined that my switch was faulty, although I have no way of knowing how detailed their investigation was (my service adviser was friendly but didn't give me many details even when asked, I think he just didn't know).
The dealer wanted $118 (plus tax) for a new 3rd gear pressure switch and an additional $80 (plus tax) in labor to remove the faulty one and replace it with the new one. I said, "No thanks." I drove the CR-V home and parked it until I could replace the switch on my own. I purchased a new 3rd gear pressure switch and the required crush washer from bkhondaparts.com for $77 (including tax, shipping, and handling) and it was delivered on Tuesday.
From further reading online, I found how tos for replacing the 3rd gear pressure switch in both a Honda Element and in various Acura vehicles, but nothing detailed for a CR-V. I'd rate the difficulty as just slightly higher than changing the oil on a CR-V, if you can do that, you can do this. I thought I'd remedy the lack of a detailed how to, so here goes...
How to replace the 3rd gear transmission pressure switch on a 3rd gen CR-V:
Tools you will need:
22mm deep socket and ratchet (I used a 3/8" drive one)
10mm socket and ratchet (I used a 1/4" drive one)
Flat head screw driver
Parts you will need:
28600-RCL-003 3rd gear pressure switch (for a 2007 CR-V LX 4wd, other years may differ)
90471-PW7-A00 crush washer for above pressure switch
Don't sue me if you hurt yourself or break your car. This is just my experience that I want to share.
ALWAYS WEAR SAFETY GLASSES! WEAR GLOVES WHEN TOUCHING TRANSMISSION FLUID! NEVER GET UNDER A CAR SUPPORTED ONLY BY A JACK!
Get the front end of the car up in the air, either on ramps (what I used), jack stands, or on a lift. You don't NEED to do this but it will make the job much easier.
Remove the negative terminal of the battery. I've never felt comfortable connecting and disconnecting sensors or other expensive circuitry when they could be powered.
Remove the splash shield, below the bumper. It's the black plastic that spans the front of the car just in front of the front jack point. To do this, you need to first remove the two 10mm bolts, one at each side of the car, in front of the little mud flap looking devices:
Next, remove the 4 plastic clips (2 on each side, in the wheel well) holding the sides of the splash guard in place. Use a flat head screw driver to pry up the middle of the clip. There's little lines on either side of the head of the clip showing you where to use the screw driver. Don't He-Man it, be gentle. If the clips turn white at all or break in any way, buy new clips.
Keep each set of clips separate from the others, they are not all the same size. Next, remove the 4 plastic clips along the front of the splash guard securing it to the bumper.
The last set of 3 clips is under the car. Remove these too. There's 2 on one side and one on the other.
Then pull the splash shield out. You'll have to bend it some on the sides to get it to release from between the bumper and the inner fender plastic cover.
If you look in through the front on the driver side, in the area now no longer covered by the splash guard, you'll see the 3rd gear pressure switch. It's the blue connector.
Remove the plug from the switch by depressing a little tab and sliding the plug off the switch. You can't see the tab in my picture because it's facing the transmission. Don't worry, you can still reach it.
Remove the old switch with the 22mm deep socket. As you get to the point where only a few threads are left connecting the switch to the transmission, it will start to leak some transmission fluid. Catch it with a small cup (I learned this the hard way). As you remove the switch entirely, about 3 to 5 oz of transmission fluid will come out (rough guess, but it's not a whole lot). Clean up the seating area where the crush washer was seated to the transmission to remove any built up gunk.
The old and new switch next to each other. New switch still has the cover on the electrical connection jack, that's why it's taller.
Put the new crush washer on the new switch and install. Tighten it as much as you can by hand, then finish it off with the 22mm socket. The shop manual says 14ft-lb of torque. I don't know who can fit a torque wrench in there, but think of it as being about as tight as you'd do an oil drain plug and you're in the ball park.
I've read that transmission fluid isn't nice when sitting on parts. I cleaned off excess transmission fluid with some brake cleaner. Make sure to shield the new switch so as to not get it covered in any brake cleaner. Also, try to avoid getting brake cleaner on other plastic parts.
Pull the cover off the switch's electrical jack and reconnect the connector. Put the splash shield back on. I recommend putting the two bolts in first then doing the clips in the same order as you removed them. Make sure when putting the bolts in that the splash shield is in between the bumper and fender liner, it makes sense once you see it.
Reconnect the battery and go for a drive!