DTC 15
The contents of this article reflect the changes called out by TSB 05-17-001Auto-cruise Control Switch System Circuit:
Connectors:
CIRCUIT OPERATION
This circuit judges the signals of each switch ("OFF," "SET," "RESUME," "CANCEL" and "MAIN") of the auto-cruise control switch. The auto-cruise control-ECU detects the state of the auto-cruise control switch by sensing the voltages shown below.
- When all switches are OFF, the ECU detects 3.5 - 5.0 volts.
- When the "SET" switch is ON, the ECU detects 0.4 - 2.3 volts.
- When the "RESUME" switch is ON, the ECU detects 2.3 - 3.5 volts.
- When the "CANCEL" switch is ON, the ECU detects 0.4 volts or less.
- When the main switch is ON, the ECU detects 7.0 volts.
DTC SET CONDITIONS
This code is output when the auto-cruise control switch "RESUME" switch, "SET" switch or "CANCEL" switch stays ON.
TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Malfunction of the auto-cruise control switch.
- Malfunction of the clock spring.
- Damaged harness or connector.
- Malfunction of the auto-cruise control-ECU
DIAGNOSIS
Required Special Tool:
- MB991223: Harness Set
STEP 1. Check the 12-Volt supply circuit voltage at auto-cruise control switch connector C-202.
1. Disconnect auto-cruise control switch connector C-202 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 1 and ground.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage approximately battery positive voltage?
YES: Go to Step 5.
NO: Go to Step 2.
STEP 2. Check auto-cruise control switch connector C-202.
Q: Is the connector damaged?
YES: Repair or replace connector.
Refer to Harness Connector Inspection.
Then check that diagnostic trouble code 15 is not output.
NO: Go to Step 3.
STEP 3. Check the clock spring.
Refer to Air Bag Modules and Clock Spring.
Q: Is the clock spring damaged?
YES: Replace the clock spring. Refer to Air Bag Modules and Clock Spring. Then check that diagnostic trouble code 15 is not output.
NO: Go to Step 4.
STEP 4. Check clock spring connector C-204.
Q: Is any connector damaged?
YES: Repair or replace connector.
Refer to Harness Connector Inspection.
Then check that diagnostic trouble code 15 is not output.
NO: Check the harness wire between ignition switch (IG1) and auto-cruise control switch connector C-204 terminal 2 for open circuit or damage. Then repair if necessary. Then check that diagnostic trouble code 15 is not output.
STEP 5. Check the output circuit 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 1 volt or less. ("CANCEL" switch is at the "ON" position.)
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage within specifications?
YES: Go to step 8.
NO: Go to step 6.
STEP 6. Check auto-cruise control switch connector C-202.
Q: Is the connector damaged?
YES: Repair or replace connector Refer to Harness Connector Inspection. Then check that diagnostic trouble code 15 is not output.
NO: Go to Step 7.
STEP 7. Check the auto-cruise control switch.
1. Disconnect auto-cruise control switch.
2. Measure the resistance between the terminals when each of the "SET", "RESUME", "CANCEL" and MAIN switch is pressed.
Q: Is the values measured correspond to those in the table?
YES: Check that diagnostic trouble code 15 is not output. If diagnostic trouble code 15 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 15 is not output.
NO: Replace the auto-cruise control switch. Then check that diagnostic trouble code 15 is not output.
STEP 8. Check the output circuit voltage at auto-cruise control-ECU connector C-107 by backprobing.
1. Do not disconnect auto-cruise control-ECU connector C-107
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between 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 1 volt or less. ("CANCEL" switch is at the "ON position.)
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage within specifications?
YES: check that diagnostic trouble code 15 is not output. If diagnostic trouble code 15 is output, replace the auto-cruise control-ECU. Then check That diagnostic trouble code is not Output,
NO: Go to step 9.
STEP 9. Check auto-cruise control-ECU connector C-107.
Q: Is the connector damaged?
YES: Repair or replace connector. Refer to Harness Connector Inspection. Then check that diagnostic trouble code 15 is not output.
NO: Go to Step 10.
STEP 10. Check the clock spring.
Refer to Air Bag Modules and Clock Spring.
Q: Is the clock spring damaged?
YES: Replace the clock spring. Refer to Air Bag Modules and Clock Spring. Then check that diagnostic trouble code 15 is not output.
NO: Go to Step 11.
STEP 11. Check auto-cruise control switch connector C-202, clock spring connector C-204.
Q: Is any connector damaged?
YES: Repair or replace connector. Refer to Harness Connector Inspection. Then check that diagnostic trouble code 15 is not output.
NO: Go to Step 12.
STEP 12. Check the harness wire between auto-cruise control switch connector C-204 and auto-cruise control-ECU connector C-107.
Q: Is any harness wire between auto-cruise control switch connector C-204 and auto-cruise control-ECU connector C-107 damaged?
YES: Repair harness wire and then check that diagnostic trouble code 15 is not output.
NO: Check that diagnostic trouble code 15 is not output. If diagnostic trouble code 15 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 15 is not output.