Dtc B B Right Front Air Bag Sensor Malfunction

Description

The front air bag sensor circuit consists of the air bag sensor assembly and front air bag sensor.

Possible Causes

DTC 15/B1156 or B1157 could be causes by a front air bag sensor malfunction.

2004 ACCESSORIES/SAFETY EQUIPMENT Toyota - Air Bag Restraint Systems

Diagnostic Procedure

1. Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM.

2. Connect negative battery cable. Turn ignition switch to ON position. Measure voltage between ground and air bag sensor assembly connector A20, terminal No. 9 (circuit SR+, Black/White wire). See Fig. 22 . Measure voltage between ground and air bag sensor assembly connector A20, terminal No. 20 (circuit SR-, Brown/White wire). If voltage in both tests is less than one volt, go to next step. If either voltage is more than one volt, go to step 8 .

3. Measure resistance between ground and air bag sensor assembly connector A20, terminal No. 9 (circuit SR+, Black/White wire). Measure resistance between ground and air bag sensor assembly connector A20, terminal No. 20 (circuit SR-, Brown/White wire). If resistance in both tests is more than one megohm, go to next step. If either resistance is less than one megohm, go to step 9 .

4. Measure resistance between air bag sensor assembly connector A20, terminals No. 9 (circuit SR+, Black/White wire) and terminal No. 20 (circuit SR-, Brown/White wire). If resistance is more than one megohm, go to next step. If is less than one megohm, go to step 10 .

5. Connect jumper wire between right front air bag sensor harness connector terminals. Measure resistance between air bag sensor assembly connector A20, terminal No. 9 (circuit SR+, Black/White wire) and terminal No. 20 (circuit SR-, Brown/White wire). If resistance is less than one ohm, go to next step. If is more than one ohm, go to step 11 .

6. Measure resistance across right front air bag sensor terminals. If resistance is 300-1500 ohms, go to next step. If resistance is not 300-1500 ohms, replace right front air bag sensor.

7. Turn ignition switch to LOCK position. Disconnect negative battery cable. Wait at least 90 seconds. Connect air bag sensor assembly connector A20 (center connector). Reconnect right front air bag sensor. Connect negative battery cable. Wait at least 20 seconds. Turn ignition switch to ON position. Clear DTCs. See CLEARING CODES under DIAGNOSTICS. Turn ignition switch to LOCK position. Wait at least 20 seconds. Turn ignition switch to ON position. Wait at least 20 seconds. Retrieve codes. See RETRIEVING CODES under DIAGNOSTICS. If DTC 15/B1156 or B1157 is displayed, replace air bag sensor assembly. If DTC 15/B1156 or B1157 is not displayed, system is functioning properly at this time. Check for intermittent fault. See AIR BAG WARNING LIGHT INTERMITTENT under DIAGNOSTIC TESTS.

8. Disconnect right front air bag sensor Yellow 4-pin sub-harness connector. Connector is located on right side of instrument panel. Measure voltage between ground and Black/White wire on front air bag sensor side of Yellow 4-pin sub-harness connector. Measure voltage between ground and Brown/White wire on front air bag sensor side of Yellow 4-pin sub-harness connector. If voltage in both tests is less than one volt, repair or replace harness or connector between air bag sensor assembly and Yellow 4-pin sub-harness connector. If voltage is more than one volt, repair or replace harness or connector between Yellow 4-pin sub-harness connector and right front air bag sensor.

9. Disconnect right front air bag sensor Yellow 4-pin sub-harness connector. Connector is located on right side of instrument panel. Measure resistance between ground and Black/White wire on front air bag sensor side of Yellow 4-pin sub-harness connector. Measure resistance between ground and Brown/White wire on front air bag sensor side of Yellow 4-pin sub-harness connector. If resistance in both tests is more than one megohm, repair or replace harness or connector between air bag sensor assembly and Yellow 4-pin sub-harness connector. If either resistance is less than one megohm, repair or replace harness or connector between Yellow 4-pin sub-harness connector and right front air bag sensor.

2004 ACCESSORIES/SAFETY EQUIPMENT Toyota - Air Bag Restraint Systems

10. Disconnect right front air bag sensor Yellow 4-pin sub-harness connector. Connector is located on right side of instrument panel. Measure resistance between Black/White and Brown/White wires on front air bag sensor side of Yellow 4-pin sub-harness connector. If resistance is more than one megohm, repair or replace harness or connector between air bag sensor assembly and Yellow 4-pin sub-harness connector. If resistance is less than one megohm, repair or replace harness or connector between Yellow 4-pin sub-harness connector and right front air bag sensor.

11. Disconnect right front air bag sensor Yellow 4-pin sub-harness connector. Connector is located on right side of instrument panel. Connect jumper wire between right front air bag sensor harness connector terminals. Measure resistance between Black/White and Brown/White wires on front air bag sensor side of Yellow 4-pin sub-harness connector. If resistance is less than one ohm, repair or replace harness or connector between air bag sensor assembly and Yellow 4-pin sub-harness connector. If resistance is more than one ohm, repair or replace harness or connector between Yellow 4-pin sub-harness connector and right front air bag sensor.

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