B1021

DTC B1021 Driver Deployment Loop Resistance High (Part 1 Of 3):

DTC B1021 Driver Deployment Loop Resistance High (Part 2 Of 3):

DTC B1021 Driver Deployment Loop Resistance High (Part 3 Of 3):

Wiring Diagram:

CIRCUIT DESCRIPTION
When you turn the ignition switch to the ON position, the inflatable restraint Sensing and Diagnostic Module (SDM) performs tests in order to diagnose malfunctions. Next, the SDM measures IGNITION 1 and the deployment loop voltages in order to verify normal voltage ranges. Then, the SDM proceeds with the Resistance Measurement test. During one portion of the Resistance Measurement test, the SDM does the following:
^ Grounds the Driver Side Low terminal 10 through an internal current sink.
^ Connects the Driver Side High terminal 9 to an internal constant current source. This current produces proportional voltage drops in the deployment loop.
^ Measures the voltage difference between Driver Side High and Driver Side Low.
^ Calculates the resistance of the driver deployment loop using the measured voltage.

CONDITIONS FOR SETTING THE DTC
^ The driver deployment loop and the passenger deployment loop are not open.
^ The driver deployment loop and the passenger deployment loop are not shorted to voltage.
^ The driver deployment loop is not shorted to ground.
^ The driver deployment loop resistance is more than 3.8 ohms. The driver deployment loop consists of the following components:
- The Inflatable Restraint steering wheel module.
- The inflatable restraint steering wheel module coil.
- The harness wiring Of the GRN/RED wire.
- The harness wiring of the GRN wire.
- The connector terminal contact.

The Resistance Measurement test checks for this malfunction. This test only occurs once each ignition cycle when IGNITION 1 is within the normal operating voltage range.

ACTION TAKEN WHEN THE DTC SETS
^ The SDM sets a diagnostic trouble code.
^ The SDM turns ON the AIR BAG warning lamp.

CONDITIONS FOR CLEARING THE DTC
^ Clear the Current DTC if the resistance of the driver deployment loop is less than 3.8 ohms and the ignition switch is cycled.
^ Clear the History DTC under the following conditions:
- You use the scan tool in order to clear the DTC.
- 250 malfunction free ignition cycles have occurred.

When you use the scan tool in order to clear the DTC and the malfunction is still not present, the DTC will not appear until the next ignition cycle.

DIAGNOSTIC AIDS
A poor connection can cause an intermittent condition. Check the following for a poor connection:
^ The connector of the inflatable restraint steering wheel module in the steering wheel column at terminal 1 and at terminal 2.
^ The upper connector of the inflatable restraint steering wheel module coil at terminal 1 and at terminal 2.
^ Terminal 9 and terminal 10 of the SDM.
^ The wire to terminal connections in the GRN/RED wire.
^ The wire to terminal connections in the GRN wire.

The diagnostic table directs the technician to note the entry value of DRIVER RESISTANCE. Comparing the value of DRIVER RESISTANCE can help determine if an intermittent condition exists.

If measurements are requested in this table, use J 39200 the Digital Multimeter with the correct terminal adapter J 35616-A from the Connector Test Adapter kit. If a check for a correct connection is requested, refer Testing for Intermittent and Poor Connections to. If a wire repair, a connector repair, or a terminal J 38125-B repair is requested, use the Terminal Wiring Repair Repair kit, and refer to Wiring Repair. Intermittents and Poor Connections

TEST DESCRIPTION
The numbers below refer to steps in the diagnostic table.
2. This test determines the deployment loop resistance that the Sensing and Diagnostic Module (SDM) measures.
3. This test checks for the correct contact and/or for corrosion of the yellow 2-way connector.
10. This test isolates the malfunction to one side of the yellow 2-way connector of the inflatable restraint module near the base of the steering column.
11. This test determines if the malfunction is in the inflatable restraint steering wheel module coil or in the inflatable restraint steering wheel module.
12. This test checks for the correct contact and/or for corrosion of the SDM connector.
14. This test checks for the correct contact and/or for corrosion of the SDM connector.
19. This test determines if the malfunction is in the GRN/RED wire.
21. This test determines if the malfunction is in the GRN wire.