Differentials - Automatic Disconnecting: Other Toyota Tundra I

COMPONENT TESTS

Note. If ADD fails to shift correctly, test ADD components for proper operation. If components are okay, check wiring circuit. See WIRING DIAGRAMS .

Scheme 26

1. Disconnect actuator connector. Measure resistance between terminal Nos. 2 and 6. (Scheme 26) Resistance should be 0.3-100 ohms. Measure resistance between terminal Nos. 2 and 6 and body ground. Resistance should be more than 0.5 ohms. If resistance value is not as specified, replace actuator assembly.
2. Apply positive battery voltage to actuator terminal No. 2 and negative battery voltage to actuator terminal No. 6. (Scheme 26) Listen for actuator engagement operation. Using an ohmmeter, check for continuity between actuator terminal Nos. 3 and 4. If there is no continuity, replace actuator.
3. Apply positive battery voltage to actuator terminal No. 6 and negative battery voltage to actuator terminal No. 2. Listen for actuator disengagement operation. Using an ohmmeter, check that there is no continuity between actuator terminals No. 3 and 4. If there is continuity, replace actuator.

Scheme 27

1. Disconnect electrical connector from ADD relay. ADD relay is located on right fender apron under hood. see scheme 1or see scheme 4. Using an ohmmeter, ensure continuity exists between relay terminal Nos. 1 and 2, Nos. 2 and 4, and Nos. 6 and 7. (Scheme 27) NOTE: There is a diode between ADD relay terminal Nos. 6 and 7. If no continuity exists, switch position of ohmmeter positive probe with negative probe and recheck.
2. Apply positive battery voltage to ADD relay terminal No. 6, and negative voltage to terminal No. 5. (Scheme 27) There should be continuity between relay terminal Nos. 1 and 3, and no continuity between terminal Nos. 1 and 2.
3. Apply positive battery voltage to ADD relay terminal No. 7, and negative voltage to terminal No. 2. (Scheme 27) There should be no continuity between relay terminal Nos. 9 and 10.
4. Apply positive battery voltage to ADD relay terminal No. 9, and negative voltage to terminal No. 10. (Scheme 27) There should be continuity between relay terminal Nos. 3 and 4, and no continuity between terminal Nos. 2 and 4. If continuity is not as specified, replace relay.

Tacoma

1. Disconnect electrical connector from ADD relay. ADD relay is located on right fender apron under hood. see scheme 3 Ensure continuity exists between relay terminal Nos. 1 and 2, Nos. 2 and 4 and Nos. 5 and 7. (Scheme 27) NOTE: There is a diode between ADD relay terminal Nos. 5 and 7. If no continuity exists, switch position of ohmmeter positive probe with negative probe and recheck.
2. Apply positive battery voltage to terminal No. 7 and negative voltage to terminal No. 5. Ensure continuity exists between terminal Nos. 1 and 3, and no continuity exists between terminal Nos. 1 and 2.
3. Apply positive battery voltage to terminal No. 7 and negative voltage to terminal No. 2. Ensure no continuity exists between terminal Nos. 9 and 10.
4. Apply positive battery voltage to terminal No. 9 and negative voltage to terminal No. 10. Ensure continuity exists between terminal Nos. 3 and 4 and no continuity exists between terminal Nos. 2 and 4. If continuity is not as specified, replace relay.

Sequoia

1. Connect actuator connector. Shift transfer shift lever into "H" position and place 2-4 selector switch in OFF position. Check ADD actuator operation by sound. Disconnect actuator connector.
2. Using an ohmmeter, ensure there is no continuity between actuator connector terminal Nos. 1 and 4, Nos. 3 and 5, and Nos. 4 and 5. (Scheme 26) Ensure there is continuity between terminal Nos. 1 and 3.
3. Connect actuator connector. Shift transfer shift lever into "H" position and place 2-4 selector switch in ON position. Check ADD actuator operation by sound. Disconnect actuator connector.
4. Using an ohmmeter, ensure there is no continuity between actuator connector terminal Nos. 1 and 3, Nos. 1 and 4, and Nos. 4 and 5. (Scheme 26) Ensure there is continuity between terminal Nos. 3 and 5. Connect actuator connector.

Tacoma & 4Runner

1. Connect actuator connector. Shift transfer shift lever/transfer operation switch to "H" (with one-touch selector) or H2 (without one-touch selector). Check ADD actuator operation by sound. Disconnect actuator connector.
2. Using an ohmmeter, ensure there is no continuity between terminal Nos. 1 and 3, Nos. 1 and 4, and Nos. 4 and 5. (Scheme 26) Ensure there is continuity between terminal Nos. 3 and 5. Connect actuator connector.
3. Shift transfer shift lever/transfer operation switch to H4 position (without one-touch selector) or turn selector switch ON (with one-touch selector). Check ADD actuator operation by sound. Disconnect actuator connector.
4. Ensure there is no continuity between terminal Nos 1 and 4, Nos 3 and 5, and Nos 4 and 5. Ensure there is continuity between terminal Nos 1 and 3. (Scheme 26) Connect actuator connector.
5. If continuity is not as specified, replace actuator assembly.

Tundra

1. Connect ADD actuator connector. Shift transfer case shift lever, or move transfer operation switch to H2 position. Listen for ADD actuator operation.
2. Disconnect ADD actuator connector. Using an ohmmeter, ensure that continuity is present between terminal Nos. 3 and 5, and that there is no continuity between terminal Nos. 1 and 3, Nos. 1 and 4, and Nos. 4 and 5. (Scheme 26) If continuity is not as specified, replace actuator assembly.
3. Connect ADD connector. Shift transfer case shift lever, or move transfer operation switch to H4 position. Listen for ADD actuator operation.
4. Disconnect ADD actuator connector. Using an ohmmeter, ensure that continuity is present between terminal Nos. 1 and 3, and that there is no continuity between terminal Nos. 1 and 4, Nos. 3 and 5, and Nos. 4 and 5. (Scheme 26) If continuity is not as specified, replace actuator assembly. Connect ADD actuator connector.