Restraint > SRSCM > Troubleshooting > B1485 Passenger Airbag Resistance too High(2nd stage)

General Description

Passenger Air bag module (hereinafter referred to PAB) located at passenger side crush pad protects passenger by reducing impact of collision.

PAB is consist of air bag, pat cover and inflator.

Air bag reduces impact of collision by fillied up gas.

Inflator keeps gas and uses it to deploy air bag on collision.

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

Dual output type airbag deploys two bags in sequence within specified time difference.

It can protect driver with less impact of gas expention force, that can reduce driver's injury.

Constituent is the same as single output type airbag.

DTC Description

The SRSCM sets DTC B1485 if the measured resistance value of PAB circuit is more 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

•	Poor connection of connected part.

•	Poor connection between shorting bar and release pin.

•	Faulty PAB.

•	Faulty SRSCM.

Enable Conditions

•	Ignition "ON"

Threshold Value

•	PAB resistance ≥ 6.1Ω

Diagnostic
Time

Qualification

•	More than 4 sec

De-Qualification

•	More than 8 sec

Specification

Test Condition	Resistance
Ignition ON	1.6 Ω ≤ PAB resistance ≤ 4.7 Ω

Schematic Diagram

Monitor Scantool Data

1.	Ignition "OFF", connect scantool.

2.	Ignition "ON" & Engine "OFF", select "Diagnostic Trouble Codes(DTC)" mode.

3.	Monitor diagnostic trouble code and present of trouble code.

4.	Using a scan tool, clear the DTC.

Is DTC present problem ?

▶ Go to "W/Harness Inspection" procedure.

▶ 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 "Verification of Vehicle Repair" 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 PAB module and connect the dummy (0957A-38200) and dummy adapter (0957A-2E110) to PAB connector of the clock spring harness connector.

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

Lay Removed PAB 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 "Main harness circuit inspection" procedure.
	▶ Substitute a known-good PAB assembly, and check for proper operation. If the problem is corrected, replace PAB and then go to "Verification of Vehicle Repair" procedure.

Main harness Circuit Inspection

1.	Ignition "OFF".

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

Disconnect PAB connector and SRSCM main harness connector.

Lay Removed PAB facing upward for unexpected air bag deploy.

Measure resistance between terminal "Low.2" and "High.2" of the PAB harness connector.

Specification : 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 and then go to "Verification of Vehicle Repair" procedure.
	▶ Substitute the SRS main harness and check for proper operation. If the problem is corrected, replace SRS main harness and then go to "Verification of Vehicle Repair" procedure.

Verification of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.

1.	Connect scantool and select "Diagnostic Trouble Codes(DTC)" mode.

2.	Using a scantool, clear the DTC.

3.	Operate the vehicle within DTC Enable conditions in General information.

Are any DTC present ?

	▶ Go to the applicable troubleshooting procedure.
	▶ System is performing to specification at this time.