DIAGNOSIS Required Special Tool: MB991223: Harness Set

STEP 1. Measure the 12-Volt supply circuit voltage at auto-cruise control switch connector C-202.

(1) Disconnect auto-cruise control switch connector C-202. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between auto-cruise control switch connector C-202 terminal 1 and ground. The measured voltage should measure battery positive voltage. (4) Turn the ignition switch to the "LOCK" (OFF) position, connect auto-cruise control switch connector C-202. Q: Is the measured voltage battery positive voltage? YES: Go to Step 6 . NO: Go to Step 2 .

STEP 2. Check auto-cruise control switch connector C-202 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connector and terminals in good condition? YES: Go to Step 3 . NO: Repair or replace connector (Refer to GROUP 00E, Harness Connector Inspection ). Then check that diagnostic trouble code 15 is not set.

STEP 3. Check the clock spring. Refer to GROUP 52B, Air Bag Modules and Clock Spring . Q: Is the clock spring in good condition? YES: Go to Step 4 . NO: Replace the clock spring (Refer to GROUP 52B, Air Bag Modules and Clock Spring ). Then check that diagnostic trouble code 15 is not set.

STEP 4. Check intermediate connector C-229-1, clock spring connectors C-204 and C-229 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? YES: Go to Step 5 . NO: Repair or replace connector (Refer to GROUP 00E, Harness Connector Inspection ). Then check that diagnostic trouble code 15 is not set.

STEP 5. Check the harness wire between junction block (fuse 2) and auto-cruise control switch connector C-202 terminal 1 for damage.

Q: Is the harness wire in good condition? YES: This malfunction is intermittent (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ). Then check that diagnostic trouble code 15 is not set. NO: Repair harness wire and then check that diagnostic trouble code 15 is not set.

STEP 6. Measure the signal voltage at auto-cruise control switch connector C-202 by backprobing.

(1) Do not disconnect auto-cruise control switch connector C-202. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 2 and ground by backprobing. Voltage should measure between 6.8 and 7.2 volts. (MAIN switch is at the "ON" position.) Voltage should measure between 3.5 and 5.0 volts. (All switches are at the "OFF" position.) Voltage should measure between 0.4 and 2.3 volts. ("SET" switch is at the "ON" position) Voltage should measure between 2.3 and 3.5 volts. ("RESUME" switch is at the "ON" position.) Voltage should measure between 1 volt or less. ("CANCEL" switch is at the "ON" position.) (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Are all of the measured voltages satisfied? YES: Go to Step 9 . NO: Go to Step 7 .

STEP 7. Check auto-cruise control switch connector C-202 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connector and terminals in good condition? YES: Go to Step 8 . NO: Repair or replace connector (Refer to GROUP 00E, Harness Connector Inspection ). Then check that diagnostic trouble code 15 is not set.

STEP 8. Check the auto-cruise control switch. (1) Remove the auto-cruise control switch (Refer to ).

(2) Measure the resistance between the terminals when each of the "CRUISE" (MAIN), "COAST/SET", "ACC/RES" and "CANCEL" switch is pressed. SWITCH POSITION RESISTANCE BETWEEN TERMINALS "CRUISE" (MAIN) switch "OFF" Terminal 1 and 2 Open circuit "CRUISE" (MAIN) switch "ON" Terminal 1 and 2 Approximately 3.9 kΩ "CANCEL" switch "ON" Terminal 2 and 3 Approximately 0 Ω "ACC/RES" switch ON Terminal 2 and 3 Approximately 910 Ω "COAST/SET" switch ON Terminal 2 and 3 Approximately 220 Ω Q: Is the measured values correspond to those in the table below? YES: Check that diagnostic trouble code 15 is not set. If diagnostic trouble code 15 is set, replace the auto-cruise control-ECU (Refer to ). Then check that diagnostic trouble code 15 is not set. NO: Replace the auto-cruise control switch (Refer to ). Then check that diagnostic trouble code 15 is not set.

STEP 9. Measure the signal voltage at auto-cruise control-ECU connector C-107 by backprobing. (1) Remove the auto-cruise control-ECU mounting nut (Refer to ).

(2) Do not disconnect auto-cruise control-ECU connector C-107. (3) Turn the ignition switch to the "ON" position.

(4) Measure the voltage between auto-cruise control-ECU connector C-107 terminal 12 and ground by backprobing. Voltage should measure between 6.8 and 7.2 volts. (MAIN switch is at the "ON" position.) Voltage should measure between 3.5 and 5.0 volts. (All switches are at the "OFF" position.) Voltage should measure between 0.4 and 2.3 volts. ("SET" switch is at the "ON" position.) Voltage should measure between 2.3 and 3.5 volts. ("RESUME" switch is at the "ON" position.) Voltage should measure between 1 volt or less. ("CANCEL" switch is at the "ON" position.) (5) Turn the ignition switch to the "LOCK" (OFF) position. Q: Are all of the measured voltages satisfied? YES: Check that diagnostic trouble code 15 is not set. If diagnostic trouble code 15 is set, replace the auto-cruise control-ECU (Refer to ). Then check that diagnostic trouble code 15 is not set. NO: Go to Step 10 .

STEP 10. Check auto-cruise control-ECU connector C-107 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connector and terminals in good condition? YES: Go to Step 11 . NO: Repair or replace connector (Refer to GROUP 00E, Harness Connector Inspection ). Then check that diagnostic trouble code 15 is not set.

STEP 11. Check the clock spring. Refer to GROUP 52B, Air Bag Modules and Clock Spring . Q: Is the clock spring in good condition? YES: Go to Step 12 . NO: Replace the clock spring (Refer to GROUP 52B, Air Bag Modules and Clock Spring ). Then check that diagnostic trouble code 15 is not set.

STEP 12. Check auto-cruise control switch connector C-202, intermediate connector C-229-1 and C-108 and clock spring connectors C-204 and C-229 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? YES: Go to Step 13 . NO: Repair or replace connector (Refer to GROUP 00E, Harness Connector Inspection ). Then check that diagnostic trouble code 15 is not set.