DTC 14
DTC 14 Auto-cruise Vacuum Pump Power Supply SystemAuto-Cruise Vacuum Pump Power Supply System Part 1:
Auto-Cruise Vacuum Pump Power Supply System Part 2:
CIRCUIT OPERATION
This circuit supplies the power to the vacuum pump. The battery positive voltage is supplied to the auto-cruise control vacuum pump by turning on the transistor at terminal number 16 of the auto-cruise control-ECU. The conditions for turning on the transistor at terminal number 16 of the auto-cruise control-ECU are as follows.
- Ignition switch "ON"
- Auto-cruise control main switch "ON"
- Stoplight switch ON
DTC SET CONDITIONS
None of the drive signals from release valve, control valve and motor of the auto-cruise vacuum pump are input to the auto-cruise control-ECU.
TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Malfunction of the stoplight switch
- 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 stoplight switch connector C-102 by backprobing.
1. Do not disconnect stoplight switch connector C-102.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between stoplight switch connector C-102 terminal 3 and ground by backprobing.
- The measured voltage should measure battery positive voltage. (When brake pedal is depressed).
- The measured voltage should measure 0 V. (When brake pedal is not depressed).
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are all of the measured voltages satisfied?
YES: Go to Step 3.
NO: Go to Step 2.
STEP 2. Check stoplight switch connector C-102 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 14.
NO: Repair or replace connector. Then check that diagnostic trouble code 14 is not output.
STEP 3. Measure the signal voltage at stoplight switch connector C-102 by backprobing.
1. Do not disconnect stoplight switch connector C-102.
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 stoplight switch connector C-102 terminal 4 and ground by backprobing.
- The measured voltage should measure battery positive voltage. (When brake pedal is depressed).
- The measured voltage should measure 0 V. (When brake pedal is not depressed).
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are all of the measured voltages satisfied?
YES: Go to Step 6.
NO: Go to Step 4.
STEP 4. Check stoplight switch connector C-102 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 5.
NO: Repair or replace connector. Then check that diagnostic trouble code 14 is not output.
STEP 5. Check the stoplight switch.
1. Disconnect stoplight switch connector C-102.
2. Connect an ohmmeter to the stoplight switch between terminals 3 and 4, and check whether there is continuity when the plunger of the stoplight switch is pushed in and an open circuit when it is released.
3. The stoplight switch is in good condition if the circuit is open when the plunger is pushed in to a depth of within 4 mm (0.2 inch) from the outer case edge surface, and if there is continuity when it is released.
Q: Is the stoplight switch in good condition?
YES: Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 14 is not output.
NO: Replace the stoplight switch. Then check that a diagnostic trouble code 14 is not output.
STEP 6. Measure the signal voltage at auto-cruise control vacuum pump connector A-26 by backprobing.
1. Do not disconnect auto-cruise control vacuum pump connector A-26.
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 vacuum pump connector A-26 terminal 1 and ground by backprobing.
- The measured voltage should measure battery positive voltage. (When brake pedal is depressed).
- The measured voltage should measure 0 V. (When brake pedal is not depressed).
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 vacuum pump connector A-26, stoplight switch connector C-102 and intermediate connector C-111 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 8.
NO: Repair or replace connector. Then check that diagnostic trouble code 14 is not output.
STEP 8. Check the harness auto-cruise control vacuum pump connector A-26 terminal 1 and wire between stoplight switch connector C-102 terminal 4 for damage.
Q: Is the harness wire in good condition?
YES: Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 14 is not output.
NO: Repair the harness wire and then check that diagnostic trouble code 14 is not output.
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.
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 auto-cruise control-ECU connector C-107 terminal 7 and ground by backprobing.
- The measured voltage should measure greater than 10 V. (When cancelling constant speed driving with the auto-cruise control CANCEL switch).
5. Measure the voltage between auto-cruise control-ECU connector C-107 terminal 8 and ground by backprobing.
- The measured voltage should measure greater than 10 V. (When decelerating with the auto-cruise control SET switch while driving at constant speed).
6. Measure the voltage between auto-cruise control-ECU connector C-107 terminal 16 and ground by backprobing.
- The measured voltage should measure 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 measured voltages satisfied?
YES: Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 14 is not output.
NO: Go to Step 10.
STEP 10. Check auto-cruise control-ECU connector C-107 and intermediate connector C-108, C-111 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 11.
NO: Repair or replace connector. Then check that diagnostic trouble code 14 is not output.
STEP 11. Check auto-cruise control vacuum pump connector A-26 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 12.
NO: Repair or replace connector. Then check that diagnostic trouble code 14 is not output.
STEP 12. 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:
a. 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.
b. 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.
c. 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 values satisfied?
YES: Go to Step 13.
NO: Replace the auto-cruise vacuum pump. Then check that diagnostic trouble code 14 is not output.
STEP 13. Check the harness wires 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 for damage.
Q: Are the harness wires in good condition?
YES: Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 14 is not output.
NO: Repair harness wire and then check that diagnostic trouble code 14 is not output.
STEP 14. Measure the signal voltage at auto-cruise control-ECU connector C-107 by backprobing.
1. Remove the auto-cruise control-ECU mounting nut.
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 auto-cruise control-ECU connector C-107 terminal 5 and ground by backprobing.
- The measured voltage should measure battery positive voltage. (When brake pedal is depressed).
- The measured voltage should measure 0 V. (When brake pedal is not depressed).
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are all of the measured voltages satisfied?
YES: Go to Step 15.
NO: Go to Step 17.
STEP 15. Check intermediate connector C-108 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 16.
NO: Repair or replace connector. Then check that diagnostic trouble code 14 is not output.
STEP 16. Check the harness wire between stoplight switch connector C-102 terminal 3 and auto-cruise control-ECU connector C-107 terminal 5 for damage.
Q: Is the harness wire in good condition?
YES: Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 14 is not output.
NO: Repair the harness wire and then check that diagnostic trouble code 14 is not output.
STEP 17. 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: Check that diagnostic trouble code 14 is not output. If diagnostic trouble code 14 is output, replace the auto-cruise control-ECU. Then check that diagnostic trouble code 14 is not output.
NO: Repair or replace connector. Then check that diagnostic trouble code 14 is not output.