Your 1992 Honda Civic won't shift into high gear -- and that is good news; if your vehicle won't shift into higher gear it means that there is a possibility that it is a smaller, less expensive problem rather than a faulty transmission. Replacing or rebuilding a faulty transmission can cost thousands of dollars and have your car in the shop for days. However, there are a variety of problems that can be misdiagnosed as a faulty transmission. Perform these troubleshooting steps before bringing your Accord to a mechanic for an expensive repair.
Prop open the hood and use a shop rag to check the automatic transmission fluid. Pull the red-capped dipstick from the engine, wipe the fluid off the stick, reinsert it, pull it back out and read the fluid level on the scored marks of the dipstick. Fill the transmission with automatic transmission fluid if it is low, as the transmission uses the fluid for hydraulic power and cannot shift properly without it. If this doesn't fix the problem, proceed to Step 2.
Remove the air intake arm with a flathead screwdriver. The air intake arm runs from the air cleaner box to the intake manifold and has two circular clamps held into place with retaining screws. Unfasten the screws with the flathead screwdriver and lift the air intake arm out of the engine compartment.
Look at the back end of the transaxle through the space left by the air intake arm. A small electronic plug sits on top of the transaxle; it has three wires running from it. This is the speed sensor that relays information to the ECU computer that controls the transmission.
Reach into the engine and remove the wiring harness from the speed sensor by unfastening its clip with your fingers. Use a 10-mm socket to remove the speed sensor from its port and install a new speed sensor with the same socket. Plug the wiring harness back into place.
Replace the air cleaner arm by fastening the screws of the circular clamps with a flathead screwdriver. Test drive the vehicle; if the car drives smoothly and is capable of reaching higher gears than it was indeed a faulty speed sensor.
Expose the ECU computer by removing the lower dashboard kick panel in the front passenger side of the car with your hands. Pull the lips of the floor carpet back just under the kick panel where the carpet meets the firewall. The ECU computer is the larger black panel on the left behind the kick panel and carpet.
Remove the metal belt bracket holding the ECU in place by using a socket wrench to unfasten the two retaining bolts at each end of the belt. Pull the ECU away from its terminal and unplug the wiring harnesses with your fingers.
Take the ECU computer to a professional for a diagnostic. The ECU, or electronic control unit, is a computer that controls all the electronic functions of your vehicle. It can malfunction and go into "Limp Mode" which will only allow the car to function in lower gears; so that you may limp the vehicle to a garage.
Insert the reprogrammed ECU back into its port and plug the wiring harnesses back in with your fingers. Place the metal belt bracket back over the ECU and tighten the retaining bolts with the appropriate socket wrench. Replace the kick panel with your hands and roll the carpet back to the firewall.
Test drive the vehicle to see if the ECU had malfunctioned. It will drive smoothly and shift into higher gear if the ECU was the problem. If your Accord still won't reach high gears, proceed to Step 11.
Limp the vehicle to the garage to have the complex transmission rebuilt, adjusted or replaced.
