Checking the Honda Civic automatic transmission shift solenoid
Materials:
* Multimeter
* Automatic transmission wiring diagram
* Chassis assembled with automatic transmission
Procedure:
1. Safety First: Make sure the engine is off and the shift lever is in the “P” (Park) position.
2. Locate the shift solenoids: The shift solenoids are usually located on the left side of the automatic transmission, near the oil pan.
3. Identify Solenoids: Refer to the transmission wiring diagram to correctly identify the solenoids.
4. Resistance check: Disconnect the connector from the solenoid. Set the multimeter to resistance measurement mode (?). Touch the multimeter probes to the two solenoid terminals. The resistance should be around 12-18 ohms for a good solenoid.
5. Open/short test: Set the multimeter to continuity test mode (beep). Touch one probe to one solenoid terminal, and the other probe to the automatic transmission housing. An audible signal should be heard indicating that continuity exists between the terminal and the chassis. Repeat for the other terminal. The absence of an audible signal indicates an open circuit or short circuit.
6. Check Power: Reconnect the connector to the solenoid. Set the multimeter to voltage (V) mode. Touch one probe to the positive terminal of the solenoid, and the other probe to the automatic transmission housing (negative terminal). When the ignition is on, the voltage should be about 12 volts.
7. Activation Test: Turn on the engine and shift into a gear that activates the solenoid (refer to the wiring diagram). The voltage at the solenoid should drop to 0 volts when the gear is fully engaged.
Interpretation of results:
* Normal Solenoid: Resistance between 12-18 ohms, no opens or shorts, power present and proper activation.
* Defective Solenoid: Abnormal resistance values, open or short circuits, lack of power or activation.
Notes:
* If a faulty solenoid is found, replace it with a new one.
* Clean solenoids and connectors before installing new ones.
* Fill with fresh automatic transmission fluid after replacing the solenoids.
*If you are unsure of the procedure, consult a qualified mechanic.