Vauxhall ADAM error code p00b3.

Engine warning light illuminated. Code P00b3 on OBDII. Changed radiator coolant temperature sensor, but didn't solve problem. Checked old sensor in boiling water, and resistance went down from 1.6kohms and continued falling, indicating that the sensor was not faulty. Wiring looks ok. Checked voltage at sensor plug and measured 5V, indicating that ECU is sending the correct voltage.