DTC 12

Vehicle Speed Sensor Circuit:

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 kph (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 speedometer.
1. Adjust the pressure of the tires to the specified level.

CAUTION
Place the transfer shift lever in "2H."




2. Set the vehicle onto a speedometer tester and use wheel chocks to hold the front wheels.

CAUTION: Do not operate the clutch suddenly. Do not increase/decrease speed rapidly while testing.




3. Check the speedometer indicator range is within the standard values.
If any value are outside the allowable range, go to Step 3. If the above values are satisfied, go to Step 2.




STEP 2. Check the circuit at the C-35 auto-cruise control-ECU.
1. Disconnect the connector C-35 and measure at the harness side.
2. Measure the voltage between terminal 10 and ground.
- Voltage should be 4.5 volts or more.

If the voltage is below the specification, go to Step 4. If the voltage meets the specification, go to Step 5.




STEP 3. 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 voltage between terminals 2 and 3, go to step 5.

If there is not voltage, replace the sensor. Then check that a diagnostic trouble code is not output.




STEP 4. Check harness connector C-35 at the auto-cruise control-ECU for damage.

If harness connector C-35 is damaged, repair or replace it. Refer to Harness Connector Inspection. Check that a diagnostic trouble code is not output.







STEP 5. Check the harness wires between the auto-cruise control-ECU connector C-35 and the vehicle speed sensor connector B-09.

If the any harness wire between the auto-cruise control-ECU connector C-35 and the vehicle speed sensor connector B-09 is damaged, repair or replace it. Refer to vehicle level Testing and Inspection. Check that a diagnostic trouble code is not output.

If the harness wires are in good condition, replace the auto-cruise control-ECU. Check that a diagnostic trouble code is not output.






NOTE: After checking intermediate connector C-29, inspect the wire. If the intermediate connector C-29 is damaged, repair or replace it. Refer to vehicle level Testing and Inspection. Check that a diagnostic trouble code is not output.