DTC 11
CIRCUIT OPERATION
- A toothed ABS rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
- The amount of voltage generated at each wheel is determined by the clearance between the ABS rotor teeth and the wheel speed sensor, and by the speed of rotation.
- The wheel speed sensors transmit the frequency of the voltage pulses and the amount of voltage generated by each pulse to the ABS electronic control unit (ABS-ECU).
- The ABS hydraulic unit modulates the amount of braking force individually applied to each wheel cylinder.
ABS DTC SET CONDITIONS
DTCs 11, 12, 13, 14 are output when signal is not input due to breakage of the (+) or (-) wire of one or more of the four wheel-speed sensors. DTCs 21, 22, 23, 24 are output in the following cases:
- Open circuit is not found but no input is received by one or more of the four wheel-speed sensors at 10 km/in (6 mph) or more.
- Sensor output drops due to a malfunctioning sensor or warped ABS rotor.
TROUBLESHOOTING HINTS
The most likely causes for these DTCs to set are.
DTC 11, 12, 13, 14
- Malfunction of the wheel speed sensor
- Damaged wiring harness and connector
- Malfunction of the hydraulic unit
DTC 21, 22, 23, 24
- Malfunction of the wheel speed sensor
- Damaged wiring harness and connector Malfunction of the hydraulic unit
- Malfunction of the ABS rotor
- Malfunction of the wheel bearing
- Excessive clearance between the sensor and ABS rotor
DIAGNOSIS
STEP 1. Check the wheel speed sensor installation.
If the wheel speed sensor is bolted securely in place at the front knuckle or the rear axle housing, go to Step 2.
If the wheel speed sensor is not bolted securely in place at the front knuckle or the rear axle housing, install it properly.
Then confirm that a diagnostic trouble code is not output.
STEP 2. Check wheel speed sensor circuit at the ABS-ECU connector A-85.
1. Disconnect connector A-85 and measure at the harness side.
2. Measure the resistance between the ABS-ECU connector terminals 1 and 2, 3 and 4, 18 and 19, 20 and 21.
Standard Value: 1.3 - 1.5 k Ohms
If the resistance is not within the standard value, go to Step 3.
If the resistance is within the standard value, go to Step 4.
STEP 3. Check harness connectors A-18, A-31, E-29, E-39 and A-85 for damage.
If the harness connectors are damaged, repair or replace them. Then confirm that a diagnostic trouble code is not output.
If the harness connectors are in good condition, go to Step 5.
STEP 4. Check the wheel speed sensor output voltage.
Output Voltage:
When measured with a voltmeter: 70 mV or more
When measured with oscilloscope (maximum voltage): 200 mV or more
If the voltage is below the specification, go to Step 6.
If the voltage meets the specification, go to Step 7.
STEP 5. Check the harness wires between wheel speed sensor connectors A-18, A-31, E-29, E-39 and ABS-ECU connector A-85.
NOTE: After inspecting intermediate connectors C-17 and E-45, inspect the wire. If intermediate connector C-17 or E-45 is damaged, repair or replace it.
Then confirm that a diagnostic trouble code is not output.
If any harness wires between the wheel speed sensor connectors A-18, A-31, E-29, E-39 and ABS-ECU connector A-85 are damaged, repair them. Then confirm that a diagnostic trouble code is not output.
STEP 6. Check the wheel speed sensor.
If there is damage in any of the check items, replace the damaged wheel speed sensor.
Check items:
Wheel speed sensor internal resistance
Standard value: 1.3 - 1.5 k ohms
Wheel speed sensor insulation resistance
Standard value: 100 k ohms
Toothed ABS rotor check
Then confirm that a diagnostic trouble code is not output.
If the wheel speed sensor is in good condition, go to Step 8.
STEP 7. Check the harness connector A-85 for damage.
If the harness connector is damaged, repair or replace it.
Then confirm that a diagnostic trouble code is not output.
If the harness connector is in good condition, replace the hydraulic unit. Then confirm that a diagnostic trouble code is not output.
STEP 8. Check the toothed ABS rotor.
Confirm whether ABS rotor teeth are broken or damage.
If any ABS rotor teeth are broken or damaged, replace it. Then confirm that a diagnostic trouble code is not output.
If the ABS rotors are in good condition, go to Step 9.
STEP 9. Check the wheel bearing.
Then confirm that a diagnostic trouble code is not output.