DTC 12
Vehicle Speed Censor Circuit:
Connectors:
CIRCUIT OPERATION
This circuit checks the operation of the vehicle speed sensor.
When the vehicle moves forward and reverses, the sensor turns ON and OFF repeatedly.
DTC SET CONDITIONS
The vehicle speed signals from the vehicle speed sensor are not input to the auto-cruise control-ECU when the vehicle speed is 40 km/h (25 mph) or more.
TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Malfunction of the vehicle speed sensor.
- Damaged connector and harness.
- Malfunction of the auto-cruise control-ECU.
DIAGNOSIS
STEP 1. Check the vehicle speed sensor.
1. Remove the vehicle speed sensor and connect a 3 - 10 kohms resistor as shown in the illustration.
2. Turn the shaft of the vehicle speed sensor and check that there is voltage between terminals 2 - 3. (One turn = four pulses)
If there is a voltage between terminals 2 and 3, go to Step 2.
If there is no voltage, replace the vehicle speed sensor. Then check that diagnostic trouble code 12 is not output.
STEP 2. Check the vehicle speed sensor power supply circuit.
1. Disconnect harness connector B-36
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 1 and ground.
- Voltage should be system voltage. If system voltage, go to Step 5.
If not system voltage, go to Step 3.
STEP 3. Check harness connector B-36
If harness connector B-36
Then check that diagnostic trouble code 12 is not output. If harness connector B-36
STEP 4. Check the harness wire between vehicle speed sensor connector B-36
If the any harness wires between the vehicle speed sensor connector B-36
Then check that diagnostic trouble code 12 is not output. If the harness wires are in good condition, go to Step 5.
NOTE: After checking intermediate connector C-28, inspect the wire. If the intermediate connector C-28 is damaged, repair or replace it. Refer to Harness Connector Inspection. Check that diagnostic trouble code 12 is not output
STEP 5. Check the vehicle speed sensor ground circuit.
1. Disconnect harness connector B-36
2. Check for the continuity between terminal 2 and ground.
- Should be less than 2 ohms. If less than 2 ohms, go to Step 8. If open loop, go to Step 6.
STEP 6. Check harness connector B-36
If harness connector B-36
Then check that diagnostic trouble code 12 is not output. If harness connector B-36
STEP 7. Check the harness wires between vehicle speed sensor connector B-36
If any harness wires between the vehicle speed sensor connector B-36
Then check that diagnostic trouble code 12 is not output. If the harness wires are in good condition, go to Step 9.
STEP 8. Check harness connector B-36
If harness connector B-36
Then check that diagnostic trouble code 12 is not output. If harness connector B-36
STEP 9. Check harness connector C-20 at auto-cruise control-ECU for damage.
If harness connector C-20 is damaged, replace it. Refer to Harness Connector Inspection.
Then check that diagnostic trouble code 12 is not output. If harness connector C-20 is in good condition, go to Step 10.
STEP 10. Check harness wires between vehicle speed sensor connector B-36
If any harness wires between the vehicle speed sensor connector B-36
Then check that diagnostic trouble code 12 is not output.
If the harness wires are in good condition, replace the auto-cruise control-ECU.
Then check that diagnostic trouble code 12 is not output.
NOTE: After checking intermediate connectors C-28 and C-77, inspect the wire. If the intermediate connectors C-28 and C-77 are damaged, repair or replace them. Refer to Harness Connector Inspection. Check that diagnostic trouble code 12 is not output.