Inspection Procedure 4
When the Selector Lever is Moved to "N" Range, Auto-cruise Control is not Cancelled .Transmission Range Switch Circuit:
CIRCUIT OPERATION
This circuit transmits the "N" or "P" position signal of the transmission range switch to the auto-cruise control-ECU. When the transmission range switch is at the "N" or "P" position, auto-cruise control-ECU terminal number 13 will receives 0 volt.
TECHNICAL DESCRIPTION (COMMENT)
The cause is probably an open-circuit in the output signal circuit in "N" range.
TROUBLESHOOTING HINTS
- Malfunction of the transmission range switch.
- Damaged harness or connector.
- Malfunction of the auto-cruise control-ECU.
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
STEP 1. Check the output circuit voltage at transmission range switch connector B-16 by backprobing.
1. Do not disconnect transmission range switch connector B-16.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between transmission range switch connector B-16 terminal 10 and ground by backprobing.
- The measured voltage should measure battery positive voltage. (When select lever is in a position other than "N" range.)
- The measured voltage should measure 0.5 volts or less. (When select lever is in "N" range.)
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are all of the measured voltages satisfied?
YES: Check that the malfunction is eliminated. If the malfunction is eliminated, replace the auto-cruise control-ECU. Then check that the malfunction is eliminated.
NO: Go to Step 2.
STEP 2. Check transmission range switch connector B-16 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. Then check that the malfunction is eliminated.
STEP 3. Check the circuit at the transmission range switch.
1. Disconnect the transmission range switch connector B-16.
2. Measure the continuity transmission range switch connector terminals.
Q: Does the continuity meet the table?
YES: Go to Step 4.
NO: Replace the transmission range switch. Then check that the malfunction is eliminated.
STEP 4. 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.
4. Measure the voltage between auto-cruise control-ECU connector C-107 terminal 13 and ground by backprobing.
- The measured voltage should measure battery positive voltage. (When select lever is in a position other than "N" range).
- The measured voltage should measure 0.5 volts or less. (When select lever is in "N" range).
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are all of the measured voltages satisfied?
YES: Check that the malfunction is eliminated. If the malfunction is eliminated, replace the auto-cruise control-ECU. Then check that the malfunction is eliminated.
NO: Go to Step 5.
STEP 5. 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 6.
NO: Repair or replace connector. Then check that the malfunction is eliminated.
STEP 6. Check intermediate connector C-105 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 7.
NO: Repair or replace connector. Then check that the malfunction is eliminated.
STEP 7. Check the harness wire between transmission range switch connector B-16 terminal 10 and auto-cruise control-ECU connector C-107 terminal 13 for damage.
Q: Is the harness wire in good condition?
YES: Check that the malfunction is eliminated. If the malfunction is eliminated, replace the auto-cruise control-ECU. Then check that the malfunction is eliminated.
NO: Repair the harness wire and then check that the malfunction is eliminated.