How to Perform an Automatic Transmission
Diagnostics on a Honda Civic (1996-2000)

Not sure where to start? Take a look at our Job of the Month. This month we walk you through performing an automatic transmission diagnostic on a Honda Civic (1996-2000). With the right parts and the right knowledge, you'll soon be hitting the open road.

Every vehicle is different, so when it comes to maintenance and repairs, always follow the vehicle's owner's manual. Don't work with a Philips when it calls for flat. Substituting tools can compromise your safety or your vehicle's performance.

Safety should be your number one priority, so don't smoke, drink alcoholic beverages, or wear a necktie. And watch out for hot objects, sharp instruments, hazardous materials and other potential safety hazards in and around your workspace.

And finally, when the fun turns to frustration or if the job requires specialized knowledge beyond your abilities, seek the assistance of a Parts Pro, professional mechanic or installer. The last thing we want is someone getting hurt.

Mainshaft Speed Sensor
	Make sure mainshaft and counter shaft speed sensors are installed correctly.
	Disconnect the mainshaft speed sensor wiring connector.
	Measure the resistance between sensor terminals.
	If resistance is not 400-600 ohms, replace the mainshaft sensor.
	If the resistance is 400-600 ohms disconnect the 25-pin PCM harness connector.
	Check for continuity between ground and 25-pin PCM harness connector, terminal 15 (red wire), and terminal 14 (white wire)
	If continuity is present, repair short to ground in red or white wire between PCM and main shaft sensor.
	Measure the resistance between 25-pin PCM harness connector, terminal 15 (red wire) and 14 (white wire).
	If the resistance is 400-600 ohms, check for loose PCM harness connectors.
	Replace PCM with a new unit if necessary.
	If the resistance is not 400-600 ohms, disconnect the mainshaft speed sensor harness.
	Check Red wire for continuity between 25-pin PCM harness connector, and the mainshaft speed sensor harness.
	If continuity is not present, repair open in red wire between 25-pin PCM harness connector, and the mainshaft speed sensor harness.
	Check white wire for continuity between 25-pin PCM harness connector, terminal 14 and mainshaft speed sensor harness connector.
	If continuity is present, check for loose PCM harness connectors.
	Replace PCM with a new unit if necessary.
	If continuity is not present, repair the open in the white wire between 25-pin PCM harness connector and mainshaft speed sensor harness connector.
Back to top

Countershaft Speed Sensor
	Make sure the countershaft speed sensor is installed correctly.
	Disconnect the countershaft speed sensor wiring connector.
	Measure the resistance between sensor terminals.
	If resistance is not 400-600 ohms, replace the countershaft sensor.
	If the resistance is 400-600 ohms disconnect the 25-pin PCM harness connector.
	Check for continuity between ground and 25-pin PCM harness connector, terminal 22 (green wire), and terminal 23 (blue wire)
	If continuity is present, repair short to ground in green or blue wire between PCM and countershaft sensor.
	Reconnect the countershaft speed sensor harness.
	Measure the resistance between 25-pin PCM harness connector, terminal 22 (green wire) and 23 (blue wire).
	If the resistance is 400-600 ohms, check for loose PCM harness connectors.
	Replace PCM with a new unit if necessary.
	If the resistance is not 400-600 ohms, repair loose connection or open in green or blue wire between 25-pin PCM harness connector and countershaft speed sensor harness connector.
Back to top

Shift Control System
	Road test vehicle at or over 20kmph for more than 30 seconds in 2nd, 3rd, and 4th gear.
	Using an OBDII code reader, check for any DTCs. (diagnostic trouble codes)
	See your local PartSource for free instructions on how to fix the different DTCs.
Back to top

See you local PartSource for FREE print out instructions including specified torque specs, and figures.