DTC 11
DIAGNOSTIC TROUBLE CODE PROCEDURESDTC 11: Auto-cruise Vacuum Pump Drive System
Auto-Cruise Vacuum Pump System Circuit:
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. Measure the signal voltage at auto-cruise control-ECU connector C-21 by backprobing.
1. Do not disconnect auto-cruise control-ECU connector C-21.
2. Turn the ignition switch to the ON position and the auto-cruise control MAIN switch to the ON position.
3. Measure the voltage between auto-cruise control-ECU connector C-21 terminal 7 and ground by backprobing.
- The voltage should measure greater than 10 V. (When canceling constant speed driving with the auto-cruise control CANCEL switch).
4. Measure the voltage between auto-cruise control-ECU connector C-21 terminal 8 and ground by backprobing.
- The voltage should measure greater than 10 V. (When decelerating with the auto-cruise control SET switch while driving at constant speed).
5. Measure the voltage between auto-cruise control-ECU connector C-21 terminal 16 and ground by backprobing.
- The voltage should measure battery positive voltage. (When the motor is stopped during a constant road speed).
6. Turn the auto-cruise control MAIN switch to the OFF position and the ignition switch to the LOCK (OFF) position.
Q: Are all of the measured voltages satisfied?
YES: Check that DTC 11 is not set. If DTC 11 is not set, It can be assumed that this malfunction is intermittent. (Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction). If DTC 11 is set, replace the auto-cruise control-ECU , and then go to Step 5.
NO: Go to Step 2.
STEP 2. Check auto-cruise control vacuum pump connector A-01, intermediate connector C-212 and auto-cruise control-ECU connector C-21 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 3.
NO: Repair or replace the faulty connector. (Refer to Harness Connector Inspection). Go to Step 5
STEP 3. Check the auto-cruise control vacuum pump.
1. Disconnect the vacuum hose from the auto-cruise control vacuum pump and connect a vacuum gauge to the vacuum pump.
2. Disconnect the auto-cruise control vacuum pump connector A-01.
3. Check the auto-cruise control vacuum pump and valves according to the following procedure:
- Connect the positive battery terminal to auto-cruise control vacuum pump connector A-01 terminal 1, and the negative battery terminal to terminals 2, 3, and 4. The vacuum gauge should read greater than 27 kPa (8.0 in.Hg).
- The vacuum should be maintained when terminal 4 is disconnected from the negative battery terminal while terminals 1, 2, and 3 remain connected. 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. The vacuum gauge should read 0 kPa (0 in.Hg) when terminal 3 is disconnected from the negative battery terminal while terminals l and 2 remain connected.
4. Connect the auto-cruise control vacuum pump connector A-01.
Q: Are all of the above values satisfied?
YES: Go to Step 4.
NO: Replace the auto-cruise control vacuum pump. Go to step 5.
STEP 4. Check the harness wire between auto-cruise control vacuum pump connector A-01 terminal 2, 3, 4 and auto-cruise control-ECU connector C-21 terminal 7, 8, 16 for damage.
Q: Is the harness wire in good condition?
YES: Check that DTC 11 is not set. If DTC 11 is not set, It can be assumed that this malfunction is intermittent. (Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction). If DTC 11 is set, replace the auto-cruise control-ECU, and then go to Step 5.
NO: Repair the damaged harness wire Go to Step 5.
STEP 5. Check the diagnostic trouble codes.
Q: Is DTC 11 set?
YES: Go to Step 1.
NO: This procedure is complete.