VERACRUZ(EN) >2008 > G 3.8 DOHC > Restraint > Troubleshooting>B1478  
General Description
Curtain Airbag (hereinafter referred to CAB)is located at driver and passenger side of headliner. It protects passenger's head and shoulder from fragments of glass or something sharpen caused by overturn. CAB is consist of air bag 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 CAB directly, Current of measuring device may cause unexpected air bag deploy.
DTC Description
The SRSCM sets DTC B1473/B1477 if the measured resistance value of DCAB/PCAB circuit is more than the threshold value.
The SRSCM sets DTC B1474/B1478 if the measured resistance value of DCAB/PCAB 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
Poor connection of connected part.
Poor connection between shorting bar and release pin.
Faulty CAB.
Faulty SRSCM.
Enable Conditions
Ignition "ON"
Threshold Value
B1473
B1477
CAB Resistance ≥ 6.1Ω
B1474
B1478
CAB Resistance ≤ 1.1Ω
Diagnostic
Time
Qualification
More than 4 sec
De-Qualification
More than 8 sec

Specification
Test Condition
Resistance
Ignition ON
1.6Ω < CAB resistance < 4.7Ω

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 scantool, clear the DTC.

5.
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.
3.
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.
3.
Disconnect CAB module and connect the dummy (0957A-38200) and dummy adapter (0957A-2G000) to main harness connector.
If dummy and dummy adaptor are not able to be prepared, use a known-good CAB or 2Ω resistor.
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.

6.
Is DTC present problem ?

▶ Go to "Main harness circuit inspection" procedure.

▶ Substitute a known-good CAB assembly, and check for proper operation.
If the problem is corrected, replace CAB 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.
3.
Disconnect CAB connector and SRSCM main harness connector.
4.
Measure resistance between terminal "Low" and "High" of the CAB harness connector.

Specification : approx. 1 Ω below

5.
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
Refer to the DESCRIPTION in this TROUBLESHOOTING section.