DTC 11

Auto-cruise Vacuum Pump Drive System Circuit:

Connectors:

CIRCUIT OPERATION
This circuit activates the vacuum pump used to accelerate/decelerate, set, and cancel the vehicle speed.
The auto-cruise control-ECU controls the control valve, release valve, and motor by turning the transistor in the ECU on and off

DTC SET CONDITIONS
Any drive signal for the release valve, control valve or motor is not input to the auto-cruise control-ECU.

TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Malfunction of the auto-cruise vacuum pump.
- Damaged harness or connector
- Malfunction of the auto-cruise control-ECU.

DIAGNOSIS

Required Special Tool:
- MB991223: Harness Set

STEP 1. Check the output circuit voltage at auto-cruise control-ECU connector C-107 by backprobing.
1. Remove the auto-cruise control-ECU mounting nuts.
2. Do not disconnect auto-cruise control-ECU connector C-107.
3. Turn the ignition switch to the "ON" position and the auto-cruise control main switch to the "ON" position.




4. Measure the voltage between terminal 7 and ground by backprobing.
- Voltage should be battery positive voltage. [When decelerating with the "SET" switch while driving at constant speed (Release valve open).]

5. Measure the voltage between terminal 8 and ground by backprobing.
- Voltage should be battery positive voltage. [When decelerating with the "SET" switch while driving at constant speed. (Control valve open).]

6. Measure the voltage between terminal 16 and ground by backprobing.
- Voltage should be battery positive voltage. (When the motor is stopped during a constant road speed.)

7. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Are all of the above values satisfied?

YES: Check that diagnostic trouble code 11 is not output. If diagnostic trouble code 11 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 11 is not.

NO: Go to Step 2.







STEP 2. Check auto-cruise control-ECU connector C-107 and intermediate connector C-108, C-111.

Q: Is the connector damaged?

YES: Repair or replace connector. Refer to Harness Connector Inspection. Then check that diagnostic trouble code 11 is not output.

NO: Go to Step 3.




STEP 3. Check auto-cruise control vacuum pump connector A-26.

Q: Is the connector damaged?

YES: Repair or replace connector. Refer to Harness Connector Inspection. Then check that diagnostic trouble code 11 is not output.

NO: Go to Step 4.

STEP 4. Check the auto-cruise vacuum pump.
1. Disconnect the vacuum hose from the auto-cruise vacuum pump and connect a vacuum gauge to the vacuum pump.
2. Disconnect the vacuum pump connector.




3. Check the auto-cruise vacuum pump and valves according to the following procedure:
- Connect the positive battery terminal to auto-cruise vacuum pump connector terminal 1, and the negative battery terminal to terminals 2, 3, and 4. The vacuum gauge should read 27 kPa (8.0 in Hg) or more.
- The vacuum should be maintained when terminal 4 is disconnected from the negative battery terminal while terminals 1, 2, and 3 remain connected. Then the vacuum gauge should read 0 kPa (0 in Hg) when terminal 2 is disconnected from the negative battery terminal while terminals 1, and 3 remain connected.
- The vacuum should be maintained when terminal 4 is disconnected from the negative battery terminal while terminals 1, 2, and 3 remain connected. Then the vacuum gauge should read 0 kPa (0 in Hg) when terminal 3 is disconnected from the negative battery terminal while terminals 1, and 2 remain connected.

Q: Are all of the above values satisfied?

YES: Go to Step 5.

NO: Replace the auto-cruise vacuum pump. Then check that diagnostic trouble code 11 is not output.







STEP 5. Check the harness wire between auto-cruise control vacuum pump connector A-26 terminal 2, 3, 4 and auto-cruise control-ECU connector C-107 terminal 7, 8, 16.

Q: Is any harness wire between auto-cruise control vacuum pump connector A-26 and auto-cruise control-ECU connector C-107 damaged?

YES: Repair the harness wire and then check that diagnostic trouble code 11 is not output.

NO: Check that diagnostic trouble code 11 is not output. If diagnostic trouble code 11 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 11 is not output.