A lot of people have never heard of a yaw rate sensor or even know what it does. It’s a critical part of the traction or stability control systems in modern vehicles and helps the computer determine if the vehicle is slipping or sliding sideways. Follow this Real Fix to see how the diagnosis of codes C1210 and C1234 led to the replacement of the yaw rate sensor.
Vehicle
2004 Toyota Sienna XLE 3.3L
Title
C1210, C1234, Traction Control Light On, Replaced Yaw Rate Sensor
Complaint
The customer states the traction control light is on. The customer also states the anti-lock brake system (ABS) light is on.
Cause
Confirmed the customer’s complaint and found the traction control light was on. Connected a scan tool and found codes: C1210 – Zero Point Calibration Undone and C1234 – Yaw Rate Sensor Circuit. Accessed the yaw rate sensor connector and used a multi-meter to measure power and ground. Key on, backprobed the yaw rate sensor connector for 5 Volt supply and less 100mv ground and found both were present. With the yaw rate sensor unbolted and held vertical, backprobed the connector with the multi-meter to measure voltage change when rotating yaw rate sensor by hand. Key on, backprobed the yaw rate sensor connector terminal 3 and 2 and found the specified 2.5 Volts did not change as sensor was rotated by hand. Key on, backprobed the yaw rate sensor terminal 1 and 2 and found the specified 4.5 to 5.5 Volt signal was erratic as the yaw rate sensor was rotated by hand. Disconnected the connector for the yaw rate sensor, inspected the connector, terminals and wiring harness and found no apparent faults. These test results verified the yaw rate sensor was faulty.
Correction
Replaced the yaw rate sensor, cleared codes, performed a road test and verified the vehicle operated properly. The ABS light did not illuminate and no fault codes returned.