Replace Ignition Assembly on a 2000 Honda Odyssey

The following instructable will help you replace the ignition assembly on a 2000 Honda Odyssey, a relatively old-school vehicle with last century's technology. Some caveats, however:

1. Having diagnosed my problem to some part of the ignition assembly, I wasn't interested in diagnosing and just replacing a one specific component. Given the age of the entire assembly and the multiple problems I was having, I simply decided to replace the whole thing. You, however, may wish to replace just one part of the system.
2. This instructable assumes your familiarity with advanced auto safety principles, advanced understanding of auto parts assemblies and their servicing, and that you have finally isolated the problem to the ignition assembly itself. You run the risk of accidentally slicing open your hand, jerking your hand away in horror and damaging a wiring harness, bleeding all over the fuse box, and shorting out some critical component, like the vanity light, or worse, the radio.
3. This is a parts replacement instructable and not a manual on diagnosing ignition problems. The Honda Service Manual P/N 61S0X01 is a pretty good authority for diagnostic procedures. Nonetheless, if you're reading this instructable it's because you KNOW your starter, solenoid, keys, battery, and immobilizer are all good.
4. Despite saving you a ton of money, about $500-$700 by some estimates, count on some degree of frustration, bruised hands, and, if you're careless, many more hours spent fixing your screw-up.

Let's get started!

You will be working very close to the air bag, fiddling with circuits and stubborn wiring harnesses. The last thing you want is the air bag suddenly exploding, sending that screwdriver through your forehead.

1. Three philips head machine screws hold the bottom half of the cover on to the bottom of the steering column; remove them.
2. Slip a thin, but stiff knife blade (use a pocket knife, for example) into the horizontal seam in front of the wiper control stick. Carefully twist and separate the two halves, first on the right side, then the left side. The bottom cover will be easy to remove, but you'll need to jimmy it past the column height adjustment lever after you loosen it.
3. The top cover will be harder to remove as the shift lever will be in the way. Reach under the cover, press the release lever down, and shift out of "Park" and into "Drive". You will now be able to slide the top cover over the shifter and off the column. Shift back into "Park".

Many electrical systems are tied to the ignition switch and must be disconnected. These will involve pressing in some small tab and pulling the connectors apart. In addition, two green connectors must be removed from the immobilizer.

The image above is the view as looked at from the underside and left of the steering wheel.

Once the wiring bundles are disconnected you'll be ready to remove the ignition assembly itself. I've outlined the easiest, least frustrating way to do this:

1. When viewed from above, you should see a shiny metal band with rivet-like bolts to either side. This is the clamping band that holds the ignition assembly to the column. To either side are "shear bolts". These were originally hex bolts whose heads are configured to shear off once tightened past a set torque. Look carefully and you may see some fractured circular metal in the center of the bolts; that's where the hex heads used to be. You must get past these now-featureless heads to loosen the metal band that holds the assembly in place.
2. Some people have chiseled these bolts off and others have hammered slots into them effectively turning them into slotted screws. Personally, I think you'd be nuts to be hammering like a banshee on the very structure that holds the most explosive component of a vehicle. Who knows what'll happen after reconnecting the battery! The Honda Service Manual states that the heads can be center-punched and drilled out; that may be an easier option for you.

Cut the Clamping Band Off

1. Use a Dremel and cut-off disc to carefully cut a slot through the top of the band. Cut carefully, but don't freak out if you mar the column tube a little. The metal is soft and will cut easily. Use a vacuum or rags to keep metal shavings from flying all over the place. And do NOT cut adjacent wiring!
2. Once cut, use a flat head screwdriver to peel back the halves past the column circumference. Peel those suckers back far enough and the switch will just drop of it's own accord. Don't let it cut the air bag wires underneath, however.

This part was comically difficult for me. These steps should easily save you a few hours of frustration! This harness requires getting to the major connector behind the fuse box under the drivers side dash....

Access to the Exterior of the Drivers Side Fuse Box

1. The plastic kick panel will need to be removed. However, the running board cover needs to be removed first. Use a flat screwdriver to pop the plastic hold-downs under the panel. Start at the rear and work your way forward, like illustrated in the photo above. Afterwards, remove the weird plastic nut that stabilizes the kick plate, jimmy the rubber gasket off and push the plate forward and off. It won't be easy, and a little muscle will help. You might as well inspect the massive twisted wire bundle for abrasions and exposed copper.
2. A small piece of under-dash plastic also needs to be removed. One screw on the left side, under the steering column will get you to easily remove this piece.
3. Now that the kick plate is off, pull the fuse box out about 1" by doing the following:

Release the Cable Connector.

1. Remove the nut attaching the fuse box to the metal structure.
2. Press down the tabs, as illustrated, that hold the fuse box housing to the metal structure and pull forward about one inch. It's not a lot, but it'll be enough to get a small screwdriver to press down the connector tab.
3. This connector is hard to remove....use a flat screwdriver to start levering the connection apart.
4. Get your hand in there and pull the connector off. Congratulations! That was the hardest part.

Snake Out the Wire Bundle

1. Cut the plastic wire wrangler to release the wire bundle and carefully snake the connector and up and through the wiring path. Use your smart phone to take pictures...you'll need to reverse the process soon enough.
2. Watch out for the air bag wiring! Don't damage that connection...you may compromise operation of the air bag!

If your new ignition assembly didn't include an immobilizer, you'll need to remove it from the old ignition and screw it back onto the new ignition switch. Expect to pay to have your new key transponder reprogrammed to the old keys' code. It won't work otherwise; the engine will turn over but the immobilizer will do its job and cut off fuel to the engine preventing the car from completely starting.

You cannot defeat this system by keeping an old key on the same key chain and hope that its proximity will be detected by the immobilizer. The sender must be very close, and in the correct geometry to be properly detected by the immobilizer. In other words, the sender must be built into the key.

Remove and Re-Install the Immobilizer

1. Remove the wire connectors.
2. A few machine screws will easily get the immobilizer off.
3. Install it on your new ignition assembly.

You're almost done! To make reconnecting the wire harness behind the fuse box easier, you'll want to pre-bend the wires in the correct orientation before trying to make the connection itself. Space is tight and the placement is very awkward.

Reinstallation

1. Send the connection home! Make sure it clicks solidly into place.
2. Re-connect the fuse box to its supports.
3. Clip the wire wrangler into it's receiving hole.
4. Loosely bolt the ignition assembly to the steering column.
5. Make the rest of your wiring connections
6. Test your system. If it's all good, finish up:

Finalizing Assembly

1. Reinstall kick plate and adjacent cover. Don't forget the gas cap pull lever.
2. Reinstall the steering column covers making sure that ignition key opening lines up properly with the ignition itself. Once it does, remove the covers and tighten the shear bolts to completion, that is, until the heads are sheared off.
3. Reinstall the steering column covers.

I had these intermittent problems with the vehicle ignition, which contributed to my no longer trusting the car to start 100% of the time. Who needs that!?

• Key would not turn at all: Inexplicably, the key could not be turned on occasion. Torquing the key would help release it, though. Didn't matter which key was used: spare key, original key, valet key. Evidence of worn key tabs? Worn cylinder? Who cares; just replace it!
  
• Starter solenoid would engage but engine wouldn't turn over: Sometimes torquing on the key would help, other times you could try 50 different things, 50 times in a row without success.

Reading the Honda repair forums reveals other people having similar problems, and in some cases, these are related to ignition switch recalls and Service Bulletins for later models. Was my switch somehow related to these issues? I can't say, but with 176,000 miles on this vehicle, I shouldn't be surprised by some parts wearing out.