B1347 Driver Airbag Resistance too Low (1st stage) - Automotive Repair Guides & Equipment

COMPONENT LOCATION

GENERAL DESCRIPTION

Driver Air bag module (hereinafter referred to DAB) located at center of steering wheel protects driver by reducing impact of collision.

DAB is consist of air bag, pat cover and two inflator.

There are power,circuit for ignition, gas generator and diffuser screen in inflator.

Air bag reduces impact of collision by fillied up gas.

In collision, pat cover splits and through this crack, air bag emerges and deploys.

Inflator generates gas that expands air bag.

Clock spring is located between steering wheel and column. It connects SCSRM to DAB.

Never measure resistance of DAB directly, Current of measuring device may cause unexpected air bag deploy.

DTC DESCRIPTION

The SRSCM sets DTC B1347 if the measured resistance value of DAB circuit is less than the threshold value.

*In this case, SRSCM checks if there’s any fault in circuit by sending current for a while.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible cause

DTC Strategy

Check Resistance

1.	Poor connection of connected part.

2.	Poor connection between shorting bar and release pin.

3.	Faulty DAB.

4.	Faulty Clock spring.

5.	Faulty SRSCM.

Enable Conditions

Ignition “ON”

Threshold Value

DAB 1st stage Squib resistance ≤ 2.26Ω

Diagnostic Time

Qualification

More than 2.5s

De-Qualification

More than 5s

SPECIFICATION

Test Condition	Resistance
Ignition ON	2.26Ω ≤ Squib resistance ≤ 6.0Ω

DIAGNOSTIC CIRCUIT DIAGRAM

MONITOR SCANTOOL DATA

1.	Ignition “OFF”, connect scantool.

2.	Ignition “ON”& Engine “OFF”, select “Current Data” mode.

Monitor the “Driver airbag resistance” parameter on the Scantool.

2.26Ω< Resistance of driver airbag < 6.0Ω

Reference : In a case of an open in the driver airbag circuit : FAIL

In a case of a short to battery in the driver airbag circuit: FAIL

In a case of a short to ground in the driver airbag circuit : FAIL

Fig.1) Normal Data

Is parameter displayed within specifications?

▶ Displaying nothing(no DTC) or DTC with label “H”(historical) shows that Fault is intermittent caused by poor contact in the part’s and/or SRSCM connector or was repaired and SRSCM memory was not cleared.
Thoroughly check shorting bar/shorting bar release pin and connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
▶ Repair or replace as necessary and then.

▶ Go to “W/Harness Inspection” procedure.

TERMINAL AND CONNECTOR INSPECTION

1.	Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.	Thoroughly check shorting bar/shorting bar release pin and connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and then go to “Verification of Vehicle Repair” procedure.
	▶ Go to “Squib Circuit Inspection” procedure.

SQUIB CIRCUIT INSPECTION

1.	Ignition “OFF”.

2.	Disconnect (-) terminal cable from battery and wait for 1 minutes or more.

Remove the DAB module and connect the dummy and dummy adapter to DAB connector of the clock spring harness connector.

If dummy and dummy adaptor are not able to be prepared, use a known-good DAB or 2Ω resistor.

Lay Removed DAB facing upward for unexpected air bag deploy .

4.	Connect (-) terminal cable to battery and Ignition “ON” & Engine “OFF” and wait for 30 seconds or more.

5.	Connect scantool to Data Link Connector(DLC) and clear DTC with scantool and diagnose again.

Is DTC present problem ?

	▶ Go to “Clock Spring Circuit Inspection” procedure.
	▶ Substitute a known-good DAB assembly, and check for proper operation. If the problem is corrected, replace DAB and then go to “Verification of Vehicle Repair” procedure.

CLOCK SPRING CIRCUIT INSPECTION

1.	Ignition “OFF” .

2.	Disconnect the battery (-) terminal cable from the battery and wait at least one minutes.

Remove DAB module and disconnect SRSCM connector of the clock spring harness.

Lay Removed DAB facing upward for unexpected air bag deploy .

Measure resistance between terminal “Low.1” and “High.1” of the Clock Spring harness connector.

approx. 1 Ω below

Is the measured resistance within specifications?

	▶ Go to “Main harness circuit inspection” procedure.
	▶ Substitute the Clock spring and check for proper operation. If the problem is corrected, replace Clock spring

MAIN HARNESS CIRCUIT INSPECTION

1.	Ignition “OFF”.

2.	Disconnect the battery (-) terminal cable from the battery and wait at least one minutes.

Remove DAB module and disconnect SRSCM connector of the clock spring harness.

Lay Removed DAB facing upward for unexpected air bag deploy .

Measure resistance between terminal “Low.1” and “High.1” of the DAB harness connector.

approx. 1 Ω below

Is the measured resistance within specifications?

	▶ Substitute a known-good SRSCM, and check for proper operation. If the problem is corrected, replace SRSCM
	▶ Substitute the SRSCM main harness and check for proper operation. If the problem is corrected, replace SRSCM main harness

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