B1801
DTC B1800, B1801, B1802, or B1803
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B1800
- Driver Air Bag Deployment Loop Resistance Too Low
DTC B1801
- Driver Air Bag Deployment Loop Resistance Too High
DTC B1802
- Driver Air Bag Deployment Loop Short to Ground
DTC B1803
- Driver Air Bag Deployment Loop Short to Battery
Circuit/System Description
During a frontal crash of sufficient force the inflatable restraint sensing and diagnostic module (SDM) will allow current to flow through the deployment loop in order to deploy the steering wheel module. The SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage.
There are 2 shorting bars used within the steering wheel module coil connector which will short together both steering wheel module stage 1 high circuit and steering wheel module stage 1 low circuit and both steering wheel module stage 2 high circuit and steering wheel module stage 2 low circuit when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing.
Conditions for Running the DTC
Ignition voltage is between 9-16 volts.
Conditions for Setting the DTC
B1800
The steering wheel module deployment loop resistance is low 5 times during primary check.
B1801
The steering wheel module high and/or low circuit is open for 2 seconds.
B1802
The steering wheel module high and/or low circuit is short to ground for 500 milliseconds.
B1803
The steering wheel module high and/or low circuit is short to voltage for 500 milliseconds.
Action Taken When the DTC Sets
* The SDM commands the AIR BAG indicator ON.
* The SIR system is disabled and no deployments are allowed.
Conditions for Clearing the DTC
* The condition for setting the DTC no longer exists.
* A history DTC will clear once 100 malfunction-free ignition cycles have occurred.
Reference Information
Schematic Reference
SIR Schematics ([1][2]Air Bag Systems)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
SIR System Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
* Connector Repairs (Connector Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
* J 38715-A Driver and Passenger SIR Load Tool
* J 38715-XX Load Tool Adaptor
Circuit/System Testing
Note: Refer to SIR Service Precautions (Technician Safety Information).
When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.
* The pretensioner
* The air bag module
* The SDM module
* The air bag wiring harness connector
* The SDM wiring harness connector
Note: The connector and CPA may seat independent of each other. Both the connector and CPA should seat with an audible and/or tactile click. The CPA isolates the shorting-bars within the connector allowing the deployment circuit to operate properly.
1. Verify that the steering wheel module connector and the connector position assurance (CPA) are engaged.
• If the above condition is found, make the appropriate repair.
2. Ignition OFF, disconnect the appropriate steering wheel module harness connector.
3. With the appropriate adaptor, connect special tool J 38715-A .
4. Ignition ON, verify DTC is set as current.
• If DTC is not set or is set as history, replace the steering wheel module.
5. Ignition OFF, disconnect special tool J 38715-A .
6. Disconnect the in-line connector at the steering wheel module coil.
7. With the appropriate adaptor, connect special tool J 38715-A .
8. Ignition ON, verify DTC is set as current.
• If DTC is not set or is set as history, replace the steering wheel module coil.
9. Ignition OFF, disconnect special tool J 38715-A and the appropriate adaptor.
10. Disconnect the harness connector at the SDM.
11. Ignition ON, test for less than 1 volt between steering wheel module coil connector Stage 1 terminal 2 X2 and ground.
• If not within the specified range, test the circuit for a short to voltage.
12. Test for less than 1 volt between steering wheel module coil connector Stage 1 terminal 1 X2 and ground.
• If not within the specified range, test the circuit for a short to voltage.
13. Ignition OFF, test for infinite resistance between steering wheel module coil connector Stage 1 terminal 2 X2 and ground.
• If not within the specified range, test the circuit for a short to ground.
14. Test for infinite resistance between steering wheel module coil connector Stage 1 terminal 1 X2 and ground.
• If not within the specified range, test the circuit for a short to ground.
15. Test for less then 1 ohm between Steering wheel module coil connector Stage 1 terminal 2 X2 and SDM terminal 5.
• If not within the specified range, test the circuit for an open/high resistance.
16. Test for less then 1 ohm between steering wheel module coil connector Stage 1 terminal 1 X2 and SDM terminal 6.
• If not within the specified range, test the circuit for an open/high resistance.
17. If all circuits test normal, replace the SDM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Steering Wheel Inflatable Restraint Module Replacement (Steering Wheel Inflatable Restraint Module Replacement)
* SIR/SRS Wiring Repairs (SIR/SRS Wiring Repairs)
* Control Module References (Programming and Relearning) for SDM replacement, setup, and programming