| DTC Code | DTC Name |
|---|---|
| C1273 | Low Output Signal of Rear Speed Sensor RH (Test Mode DTC) |
| C1274 | Low Output Signal of Rear Speed Sensor LH (Test Mode DTC) |
| C1277 | Abnormal Change in Output Signal of Rear Speed Sensor RH (Test Mode DTC) |
| C1278 | Abnormal Change in Output Signal of Rear Speed Sensor LH (Test Mode DTC) |
| C1415 | Rear Speed Sensor RH Output Malfunction |
| C1416 | Rear Speed Sensor LH Output Malfunction |
DESCRIPTION
Each speed sensor detects the wheel speed and sends signals to the skid control ECU (brake actuator assembly). These signals are used by the ABS.
The speed sensor rotors have rows of alternating N and S magnetic poles. The speed sensors use the frequency of output pulses to detect the vehicle speed. Because the sensor outputs digital pulses, it can detect the vehicle speed even when the vehicle is nearly stationary.
DTCs C1273, C1274, C1277 and C1278 are cleared when the speed sensor sends a vehicle speed signal or when Test Mode ends. DTCs C1273, C1274, C1277 and C1278 are output only in Test Mode.
Tech Tips
Check the connection status between the sensor connector and the vehicle wire harness.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
|---|---|---|---|
| C1273 | Low Output Signal of Rear Speed Sensor RH (Test Mode DTC) | Detected only during Test Mode. |
|
| C1274 | Low Output Signal of Rear Speed Sensor LH (Test Mode DTC) | Detected only during Test Mode. |
|
| C1277 | Abnormal Change in Output Signal of Rear Speed Sensor RH (Test Mode DTC) | Detected only during Test Mode. | Rear speed sensor rotor RH (rear axle hub and bearing assembly RH) |
| C1278 | Abnormal Change in Output Signal of Rear Speed Sensor LH (Test Mode DTC) | Detected only during Test Mode. | Rear speed sensor rotor LH (rear axle hub and bearing assembly LH) |
| C1415 | Rear Speed Sensor RH Output Malfunction | Any of the following is detected:
|
|
| C1416 | Rear Speed Sensor LH Output Malfunction | Any of the following is detected:
|
|
| Vehicle Condition | ||||
|---|---|---|---|---|
| Pattern 1 | Pattern 2 | Pattern 3 | ||
| Diagnosis Condition | - | - | - | - |
| Malfunction Status | An open in the sensor signal circuit of a malfunctioning area occurs 255 times or more. | ○ | - | - |
| At a vehicle speed of 20 km/h (12 mph) or more, noise occurs in the sensor signals of a malfunctioning wheel 75 times or more within 5 seconds. | - | ○ | - | |
| At a vehicle speed of 10 km/h (6 mph) or more, noise occurs once per rotor rotation | - | - | ○ | |
| Detection Time | - | - | 15 seconds or more. | |
| Number of Trips | 1 trip | 1 trip | 1 trip | |
Tech Tips
DTC will be output when conditions for either of the patterns in the table above are met.
| Vehicle Condition | ||||
|---|---|---|---|---|
| Pattern 1 | Pattern 2 | Pattern 3 | ||
| Diagnosis Condition | - | - | - | - |
| Malfunction Status | An open in the sensor signal circuit of a malfunctioning area occurs 255 times or more. | ○ | - | - |
| At a vehicle speed of 20 km/h (12 mph) or more, noise occurs in the sensor signals of a malfunctioning wheel 75 times or more within 5 seconds. | - | ○ | - | |
| At a vehicle speed of 10 km/h (6 mph) or more, noise occurs once per rotor rotation | - | - | ○ | |
| Detection Time | - | - | 15 seconds or more. | |
| Number of Trips | 1 trip | 1 trip | 1 trip | |
Tech Tips
DTC will be output when conditions for either of the patterns in the table above are met.
Tech Tips
for C1415 and C1416: Even after the trouble areas are repaired, the ABS warning light will not go off unless the following operations are performed:
Drive the vehicle at 30 km/h (19 mph) for 30 seconds or more and check that the ABS warning light goes off.
Clear the DTCs.
Tech Tips
DTC C1415 is for the rear speed sensor RH.
DTC C1416 is for the rear speed sensor LH.
WIRING DIAGRAM
| *a | Rear Speed Sensor RH |
| *b | Rear Speed Sensor LH |
| *c | Skid Control ECU (Brake Actuator Assembly) |
CAUTION / NOTICE / HINT
Note
When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information.
PROCEDURE
CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)
Using the GTS, check for any momentary interruption in the wire harness and connector corresponding to a DTC.
| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| RR Speed Open | Rear speed sensor RH open detection | Error or Normal | Error: Momentary interruption Normal: Normal |
- |
| RL Speed Open | Rear speed sensor LH open detection | Error or Normal | Error: Momentary interruption Normal: Normal |
- |
| Tester Display |
|---|
| RR Speed Open |
| RL Speed Open |
| OK |
|---|
| There are no momentary interruptions. |
Tech Tips
Perform the above inspection before removing the sensor and connector.
| Result | |||
|---|---|---|---|
|
| NG |
|
GO TO STEP 4 Click here |
| OK |
|
READ VALUE USING GTS (REAR SPEED SENSOR)
Turn the engine switch off.
Connect the GTS to the DLC3.
Start the engine.
Select the Data List using the GTS.
| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| RR Wheel Speed | Rear wheel speed sensor RH reading | Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) | Vehicle stopped: 0 km/h (0 mph) | When driving at constant speed: No large fluctuations |
| RL Wheel Speed | Rear wheel speed sensor LH reading | Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) | Vehicle stopped: 0 km/h (0 mph) | When driving at constant speed: No large fluctuations |
| Tester Display |
|---|
| RR Wheel Speed |
| RL Wheel Speed |
Check the speed value output from the speed sensor displayed on the GTS.
Tech Tips
Factors that affect the indicated vehicle speed include tire size, tire pressure, and tire wear. The speed indicated on the speedometer has an allowable margin of error. This can be tested using a speedometer tester (calibrated chassis dynamometer). For details about testing and the margin of error, see the reference chart.
| OK |
|---|
| The speed value output from the speed sensor displayed on the GTS is similar to the speed indicated on the speedometer. |
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK REAR SPEED SENSOR INSTALLATION Click here |
| OK |
|
RECONFIRM DTC
Turn the engine switch off.
Clear the DTCs.
Turn the engine switch off.
Start the engine.
Perform a road test.
Check if the same DTC is output.
| Result | ||||||||
|---|---|---|---|---|---|---|---|---|
|
Tech Tips
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts.
| A |
|
USE SIMULATION METHOD TO CHECK Click here |
| B |
|
REPLACE BRAKE ACTUATOR ASSEMBLY Click here |
| C |
|
REPLACE BRAKE ACTUATOR ASSEMBLY Click here |
CHECK REAR SPEED SENSOR INSTALLATION
Turn the engine switch off.
| *1 | Rear Speed Sensor |
| *a | Correct |
| *b | Incorrect |
| *c | 8.5 N*m |
| *d | No clearance |
Check the speed sensor installation.
| OK |
|---|
| There is no clearance between the sensor and rear axle carrier. |
| The installation bolt is tightened properly. |
| Torque |
| 8.5 N*m (87 kgf*cm, 75 in.*lbf) |
| Result | |||
|---|---|---|---|
|
| NG |
|
INSTALL REAR SPEED SENSOR CORRECTLY Click here |
| OK |
|
CHECK REAR SPEED SENSOR AND SENSOR ROTOR
Remove the rear speed sensor and the component with the sensor rotor.
for speed sensor: Click here
for sensor rotor: Click here
Check the speed sensor tip and speed sensor rotor.
| OK |
|---|
| No scratches, oil, or foreign matter on the sensor tip and rotor. |
Note
If no damage to the speed sensor tip is found during this inspection, do not replace the speed sensor.
If there are any ferrous metal filings stuck to the rotor, this will result in a malfunction, so confirm that the rotor is not contaminated with foreign matter before replacing the sensor.
Check the speed sensor signal after cleaning or replacement.
| Result | |||
|---|---|---|---|
|
| NG |
|
CLEAN OR REPLACE REAR SPEED SENSOR OR COMPONENT WITH SENSOR ROTOR |
| OK |
|
CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - REAR SPEED SENSOR)
Make sure that there is no looseness at the locking part and the connecting part of the connector.
Disconnect the A9 skid control ECU (brake actuator assembly) connector.
Disconnect the T25 or U27 rear speed sensor connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||
|
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
INSPECT BRAKE ACTUATOR ASSEMBLY (SENSOR INPUT)
| *A | for RH |
| *B | for LH |
| *a | Front view of wire harness connector (to Rear Speed Sensor) |
Reconnect the A9 skid control ECU (brake actuator assembly) connector.
Turn the engine switch on (IG).
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
||||||
|
Tech Tips
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts.
| Result | ||||||||
|---|---|---|---|---|---|---|---|---|
|
| A |
|
REPLACE REAR SPEED SENSOR Click here |
| B |
|
REPLACE BRAKE ACTUATOR ASSEMBLY Click here |
| C |
|
REPLACE BRAKE ACTUATOR ASSEMBLY Click here |