VERACRUZ(EN) >2008 > G 3.8 DOHC > Restraint > Troubleshooting>B1387  
General Description
STPS located underneath passenger seat detects horizental position of passenger seat and delivers it to SRSCM.
Signal of STPS is the one of major parameters that determine the way dual output type airbag deploys.
DTC Description
The SRSCM sets DTC B1387 if there is a short to ground in Driver STPS harness.
DTC Detecting Condition
Item
Detecting Condition
Possible cause
DTC Strategy
Check current(PWM type)
Short to ground in STPS harness.
Poor connection of connected part.
Faulty STPS.
Faulty SRSCM.
Enable Conditions
Ignition "ON"
Threshold Value
I > 24.9 mA
Diagnostic
Time
Qualification
More than 1 sec
De-Qualification
More than 2 sec

Specification
Test Condition
Current (A)
Ignition ON
Rearward : 12 ~ 18mA
Forward : 4 ~ 7mA

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.

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 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 "Main harness circuit inspection" 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 STPS connector and SRSCM main harness connector.
4.
Measure resistance between terminal "High" of the STPS harness connector and chassis ground.

■ Specification : ∞

5.
Is the measured resistance within specifications?

▶ Go to "Component Inspection" 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.
Component Inspection
1.
Ignition "ON" & Engine "OFF" and Using a scan tool, clear the DTC.
2.
Ignition "OFF".
3.
Disconnect the battery (-) terminal cable from the battery, and wait at least one minutes.
4.
Disconnect STPS connector .
5.
Substitute the STPS and check for proper operation.
6.
Is DTC present problem ?

▶ 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.

▶ Substitute a known-good STPS, and check for proper operation.
If the problem is corrected, replace STPS and then go to "Verification of Vehicle Repair" procedure.
Verification of Vehicle Repair
Refer to the DESCRIPTION in this TROUBLESHOOTING section.