Diagnostic Instructions

DTC Descriptors

DTC B0021 01: RF Side Deployment Loop Short to Battery

DTC B0021 02: RF Side Deployment Loop Short to Ground

DTC B0021 04: RF Side Deployment Loop Open Circuit

DTC B0021 0D: RF Side Deployment Loop Resistance Above Threshold

DTC B0021 0E: RF Side Deployment Loop Resistance Below Threshold

Diagnostic Fault Information

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
Side Impact Module - RF High Control	B0021 02	B0021 0D, B0021 04	B0021 04	B0021 01	B0021 0E
Side Impact Module - RF Low Control	B0021 02	B0021 0D, B0021 04	B0021 04	B0021 01	B0021 0E

Circuit/System Description

During a side or 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 side impact module. A shorting bar is located in the electrical connector of the side impact module. The side impact module high control circuit and low control circuit are shorted together by the shorting bar when the electrical connector is disconnected. The shorting bar helps to prevent unwanted deployment of the inflator module during servicing.

The SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If the result of any deployment loop circuit test is below specification, DTC B0021 and the appropriate symptom byte sets.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0021 01

The RF side impact module high and/or low circuit is short to voltage for 120 milliseconds.

B0021 02

The RF side impact module high and/or low circuit is short to ground for 120 milliseconds.

B0021 04

The RF side impact module high and/or low circuit is open for 120 milliseconds.

B0021 0D

The RF side impact module deployment loop resistance is greater than 3.9 ohms for 120 milliseconds.

B0021 0E

The RF side impact module deployment loop resistance is less than 1.1 ohms for 120 milliseconds.

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Diagnostic Aids

If DTC B0021 0E is setting, be certain that all circuit shorting bars are isolated after connecting circuit components. There are shorting bars in most circuit connectors, including the SDM and inline harness connectors. DTC B0021 0E will set if the shorting bars are engaged when the ignition is ON.

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

SIR System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

Each inflatable restraint module requires a specific adapter to connect the load tool to the SIR system.

Circuit/System Testing

Important: Refer to SIR Service Precautions.

When removing the connectors, inspect for terminal damage or corrosion. Inspect the connector body for damage to the locators that disengage the shorting bars when connected. Damage or corrosion to the following components requires repair or replacement of the affected component/connector:

•	Inflatable restraint module

•	SDM module

•	Front end sensor wiring harness connector

•	SDM wiring harness connector

Important: The connector and connector position assurance (CPA) may seat independent of each other. Both the connector and CPA should seat with an audible and/or tactile click. Correct connection isolates the shorting-bars within the connector allowing the deployment circuit to operate properly.

1. Verify that the inflatable restraint RF side impact module connector and CPA are engaged.

⇒	If the above condition is not found, make the appropriate repair.

2. Ignition OFF, disconnect the harness connector at the RF side impact module.
3. With the appropriate load tool adapter, connect J 38715-A or SA9409Z-A in place of the RF side impact module.
4. Ignition ON, with a scan tool, verify that DTC B0021 is set as current.

⇒	If the DTC is not set or is set as history, cycle the ignition OFF, disconnect the load tool and adapter, reconnect the harness connector at the RF side impact module, and cycle the ignition ON. If the DTC resets after reconnecting the module, replace the RF side impact module.

5. Ignition OFF, disconnect the load tool and the adapter.
6. Disconnect the harness connector at the SDM.
7. Ignition ON, test for less than 1.0 volt between the appropriate control circuit listed below and ground:

•	Control circuit terminal 20

•	Control circuit terminal 21

⇒	If not within the specified range, test the control circuit for a short to voltage.

8. Ignition OFF, test for infinite resistance between the appropriate control circuit listed below and ground:

•	Control circuit terminal 20

•	Control circuit terminal 21

⇒	If not within the specified value, test the control circuit for a short to ground.

9. Test for less than 1 ohm between the appropriate control circuit terminal and SDM terminal listed below:

•	Control circuit terminal 1 and SDM terminal 21

•	Control circuit terminal 2 and SDM terminal 20

⇒	If not within the specified range, test the control circuit for an open/high resistance.

10. If all circuits test normal, replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.