DTC C1401: Front Speed Sensor RH Malfunction; DTC C1271: Low Output Signal of Front Speed Sensor RH (Test Mode DTC); DTC C1272: Low Output Signal of Front Speed Sensor LH (Test Mode DTC); DTC C1402: Front Speed Sensor LH Malfunction: Description

The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU (master cylinder solenoid). These signals are used for brake control.

HINT:

When the connectors between the speed sensor and skid control ECU (master cylinder solenoid) are connected, the following waveform is output.

Fig 1: Speed Sensor Detects The Wheel Speed & Graph

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DTC Code	DTC Detection Condition	Trouble Area
C1401 C1402	One of the following conditions is met: At a vehicle speed of 10 km/h (6 mph) or more, the output voltage from one of the speed sensors is less than that from the other sensors for 15 seconds or more. At a vehicle speed of less than 10 km/h (6 mph), the output from one of the speed sensors is 0 km/h (0 mph) for 1 second or more. At a vehicle speed of 10 km/h (6 mph) or more, the outputs from both front speed sensors are 0 km/h (0 mph) for 15 seconds or more.	Front speed sensor RH/LH Front speed sensor rotor RH/LH Sensor installation
C1271 C1272	Stored only during test mode.	Front speed sensor RH/LH Front speed sensor rotor RH/LH Sensor installation

HINT:

DTCs C1401 and C1271 are for the front speed sensor RH.
DTCs C1402 and C1272 are for the front speed sensor LH.