B1773, B1776: Belt Tension Sensor Circuit Malfunction: Seat Belt Tension Sensor Power Source Circuit Malfunction: Description

WARNING: This page is about a different car, the 2007 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.

The belt tension sensor circuit consists of the occupant classification ECU and the belt tension sensor. The belt tension sensor sends the belt tension signal to the occupant classification ECU to control the occupant classification system.

DTCs B1773 and B1776 are recorded when a malfunction is detected in the belt tension sensor circuit.

DIAGNOSTIC TROUBLE CODE TABLE

DTC No.	DTC Detection Condition	Trouble Area
B1773 B1776	When one of following conditions met: Occupant classification ECU receives line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in belt tension sensor circuit for 2 seconds. Belt tension sensor malfunction Occupant classification ECU malfunction	No. 1 seat wire Front seat outer belt RH (Belt tension sensor) Occupant classification ECU

NOTE: Replace the occupant classification ECU, occupant classification sensor, seat cushion cover pad, seat cushion cover and seat cushion seat heater as a 5 part set (see supply set part no.).

HINT:

When DTC B1650/32 is detected as a result of troubleshooting the supplemental restraint system, check the DTCs stored in the occupant classification ECU, and perform troubleshooting for those DTCs first.
Use the intelligent tester to check for DTCs of the occupant classification ECU, otherwise the DTC cannot be read.