A link within the locking mechanism on these cars is weak. When it breaks you cannot lock or unlock the car from that particular door. To avoid this problem, you might want to consider installing a keyless remote entry system. In the meantime, here's how to fix it: (These instructions are specific to the CQ. The sedan will be similar, but some parts, such as those dealing with the window mechanism, will be different.)
Parts required:
- 893 837 287 D (driver's side) Carrier $ 4.38
- 893 837 061 B (driver's side) Lock Cyl $17.94
- N 012 411 1 Lockring $ 0.70
893 837 288 D (passenger side)
893 837 062 B (passenger side)
- Tweezers
- Medium philips screw driver
- Small flat bladed screw driver
- Snap Ring Pliers (Channel Lock model 907 with exchangeable tips)
- 13mm socket, extension, and wrench
- 4 mm hex wrench
- C-clamp or quick clamp
- Permanent marker, preferably in a highly visible color
- Waterproof grease
- Duct tape
- 1/8 inch wide wood sliver.
Open driver's door. Make sure that the window is in the up position. Remove the armrest (three 4mm hex bolts, which you may have to fish around for). Disconnect the window, seat memory, and mirror controls. This may also be a good time to replace the burned out LEDs in the respective switches. Remove the two L-shaped metal tabs which are held in place with philips headed screws. Remove a philips screw and its washer from the B-pillar edge of the door frame. Pull and hold the inside door release handle while removing its philips screw. Gently push the handle forward towards the A-pillar. Pull it out, remove the foam pad on the back, the retaining clip for the cable, and then remove the hook on the cable end from the handle. While gently pulling up on the inner door panel, pull the electrical connectors through the access holes, and remove the panel from the door.
Now the fun really begins. Take a few long pieces of tape and apply one end to the top of the window, and the other end to the upper part of interior side of the window frame. Take a permanent felt tip marker and trace around the edge of the frame to make it easy to reposition it later. Remove two 13mm hex bolts from the A-pillar edge of the door, two from the B pillar edge, and two 13mm from the bottom edge of the door. The two bottom edge bolts will also have U shaped washers acting as spacers. Note their position before moving them aside. Gently raise the rear of the frame and pull upward to provide enough access to the back of the door handle without binding the regulator cable. Use a clamp to secure part of the window frame to the outdoor crossmember.
Be careful here. If the door becomes loose while you are working on the cylinder, it is heavy enough to cause some serious damage to your arms or hands (guillotine-style). Now you will finally have somewhat limited access to the back of the lock cylinder (OK, basically the right half). Pry off the circlip holding part of the lock cam remains to the cylinder, using a small screwdriver. Carefully remove the circular spring that applies tension to the cylinder. Disconnect the other remains of the cam from the lock linkage by twisting the plastic connector and pulling out the end. Insert your key into the lock cylinder and gently pull it out. In a clean, well lit working area, use a pair of small tweezers to remove the tumblers and their tiny springs from the old cylinder. Clean them with a degreaser, dry, and regrease with either lithium or other waterproof grease.
Reinsert the key and make sure that all of the tumblers are pulled into the cylinder so that the cylinder can be reinserted into the lock assembly. Closely examine the white gear, which is part of the alarm mechanism. One of the gear teeth is only half as wide as the others. Mark the edge of the white tooth with a colored felt tip marker (more visible than black). Examine the black gearhead on the replacement cam, find the tooth that is half as wide as the others, and make a hash mark on the side of it with a knife or sharp screwdriver. The cam arm will extend toward the B-pillar, and there is a squared off tab on the lower part. There is also a squared off tab on the lock assembly. The cam tab needs to fit over the lock assembly tab, and the spring between the assembly tab and the cylinder. Place the spring onto the cam, and pretension it by putting the spring tabs on both sides of the cam tab. Then wedged a wood sliver between the spring and the cam tab to correctly position the spring and to prevent it from popping out of the cam. Gingerly take the cam/spring/splinter assembly and install it over the lock cylinder.
Remove the key from the cylinder and place some duct tape on the outside part of the cylinder to prevent it from popping out. Match the lower part of the cam (the part with the tab) to the lock assembly tab, and then turn and twist this assembly to get the hash mark on the cam to line up with the half tooth on the alarm gear. Take your time. Having both patience and an assistant reduces the aggravation. When everything is lined up properly, the cam will sit flush against the lock assembly, the wood sliver can be pushed out with a small screwdriver, and the half-toothed gears will correctly mesh. While holding this all in place, you now need to install the snap ring. Use the right-angled tips on the lock ring pliers, and hold the pliers on the right side of the cylinder assembly. (Remember that there is no access from the left half.) Reconnect the cam to the lock link.
At this point it is prudent to check the function of the alarm, otherwise,you will have to repeat this repair. Engage the lock cam that usually captures the B pillar striker, twist the key, and listen for the sound of the alarm engaging. Repeat this operation for a few cycles so that you can be sure that the alarm is properly being armed/disarmed. If it isn't, the two half-width gear teeth are not aligned with each other.
At this point, given the open access, you should lubricate the guides and pulleys of the window regulator with some water proof grease. Then bolt the window frame assembly back into the door. Take care to first align the frame using the tracing that you made with a marker prior to the removal. Close the door and check the window fitting to the door seal. Try putting a piece of paper between the window and the seal, closing the door, and then trying to pull out the paper. Realign the window if necessary. The rest of the reinstallation is the opposite of removal.
