Circuit Description
The following diagnostics are designed to diagnose circuit failures for both single stage and dual stage air bag systems. The light duty G/H models are equipped with dual stage air bags and the heavy duty G/H models are equipped with single stage air bags. The inflatable restraint steering wheel module deployment loop consists of a steering wheel module, steering wheel module coil, steering wheel module high control, and steering wheel module low control circuits. There are shorting bars used within the steering wheel module coil connector which will short together the steering wheel module high and steering wheel module low control circuits when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a diagnostic trouble code (DTC) will be stored in memory.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B0022 Driver Frontal Deployment Loop Resistance Low |
| • | DTC B0024 Driver Frontal Deployment Loop Voltage Out of Range |
| • | DTC B0026 Driver Frontal Deployment Loop Open |
| • | DTC B0042 LF/Driver Frontal Deployment (Stage 2) Resistance Low |
| • | DTC B0043 LF/Driver Frontal Deployment (Stage 2) Voltage Out of Range |
| • | DTC B0044 LF/Driver Frontal Deployment (Stage 2) Open |
Conditions for Running the DTC
Ignition 1 voltage is within the normal operating voltage range.
Conditions for Setting the DTC
| • | DTC B0022 - stage 1 or B0042 - stage 2 will set when the steering wheel module deployment loop resistance is less than 1.3 ohms for 500 milliseconds. |
| • | DTC B0024 - stage 1 or B0043 - stage 2 will set when one of the following conditions occur: |
| - | The SDM detects the voltage at steering wheel module high control is shorted to ground or voltage for 500 milliseconds. |
| - | The SDM detects the voltage at steering wheel module high control is less than 2.4 volts and steering wheel module deployment loop resistance is less than 6 ohms for 500 milliseconds. |
| • | DTC B0026 - stage 1 or B0044 - stage 2 will set when one of the following conditions occurs: |
| - | The SDM detects the steering wheel module deployment loop resistance is greater than 4.8 ohms for 500 milliseconds. |
| - | The SDM detects the voltage at steering wheel module high control is less than 2.4 volts and steering wheel module deployment loop resistance is 6 ohms or greater for 500 milliseconds. |
Action Taken When the DTC Sets
The SDM commands the AIR BAG indicator ON via Class 2 serial data.
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | You issue a scan tool CLEAR DTCs command. |
| • | A history DTC will clear once 255 malfunction-free ignition cycles have occurred. |
Diagnostic Aids
The following can cause an intermittent condition:
| • | A short between the steering wheel module high and low control circuits |
| • | An open or a high resistance in the steering wheel module high or low control circuits |
| • | A malfunctioning shorting bar on the steering wheel module coil connector |
Refer to Testing for Intermittent Conditions and Poor Connections .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step inspects the steering wheel module coil in-line connector.
-
This step tests for a malfunctioning steering wheel module or steering wheel module coil.
-
This step tests for current DTCs. If DTC B0022 or B0042 is present, test for a short between the steering wheel module high and steering wheel module low control circuits for stage 1 or stage 2. If DTC B0024 or B0043 is present, test for a short to ground or voltage in the steering wheel module high and steering wheel module low control circuits for stage 1 or stage 2. If DTC B0026 or B0044 is present, test for an open or high resistance in the steering wheel module high and steering wheel module low control circuits for stage 1 or stage 2.
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | |||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||||
Do the connectors exhibit any signs of corrosion, terminal damage, or poor connections? | Go to Step 3 | Go to Step 4 | |||||||
3 |
Did you complete the replacement? | Go to Step 11 | -- | ||||||
4 |
Important: When installing the J 38715-A Driver and Passenger Load Tool for testing the dual stage I/P module, the correct 4-way load tool adapter must be used. Failure to use the correct 4-way load tool adapter will set additional codes when testing. Does the scan tool indicate that either DTC B0022, B0024, B0026, B0042, B0043, or B0044 are current? | Go to Step 6 | Go to Step 5 | ||||||
Does the scan tool indicate that either DTC B0022, B0024, B0026, B0042, B0043, or B0044 is current? | Go to Step 9 | Go to Step 10 | |||||||
6 |
Did you find and correct the condition? | Go to Step 11 | Go to Step 7 | ||||||
Did you find and correct the condition? | Go to Step 11 | Go to Step 8 | |||||||
8 | Replace the SDM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 11 | -- | ||||||
9 | Replace the steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement . Did you complete the replacement? | Go to Step 11 | -- | ||||||
10 | Replace the steering wheel module. Refer to Control Module References for replacement, setup, and programming . Did you complete the replacement? | Go to Step 11 | -- | ||||||
11 |
Does the DTC reset? | Go to Step 2 | System OK | ||||||
