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| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
High Control | B0012 02, B0012 0E | B0012 0D | B0012 04, B0012 0D | B0012 01 | - |
Low Control | B0012 02, B0012 0E | B0012 0D | B0012 04, B0012 0D | B0012 01 | -- |
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 driver steering wheel air bag. The SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. There is a shorting bar used within the driver steering wheel air bag coil connector which will short together the driver steering wheel air bag stage high circuit and driver steering wheel air bag stage low circuit when the connector is disconnected. This will help to prevent unwanted deployment of the steering wheel air bag during servicing.
Ignition voltage is between 9-16 V.
The driver steering wheel air bag deployment loop is shorted to voltage for 2 seconds.
The driver steering wheel air bag deployment loop is shorted to ground for 2 seconds.
The driver steering wheel air bag deployment loop is open for 2 seconds.
The driver steering wheel air bag deployment loop resistance is greater than 4.4 Ω for 2 seconds.
The driver steering wheel air bag deployment loop resistance is less than 1.7 Ω for 2 seconds.
| • | The SDM requests the instrument cluster to illuminate the AIR BAG indicator. |
| • | The SDM will store a DTC, however if an event occurs the system will still attempt deployment. |
| • | The condition for setting the DTC is no longer exists. |
| • | A history DTC will clear once 100 malfunction-free ignition cycles have occurred. |
Note: The following diagnostic aids apply for both current and history DTCs.
A worn steering wheel air bag coil can cause a repeated history DTC to set. To verify this condition, turn the steering wheel 360 degrees in one direction then back 360 degrees in the other direction, multiple times, while viewing the scan tool Deployment Loop Resistance 1 and 2 parameters.
An incorrectly installed connector position assurance (CPA) or incorrectly seated connector can cause a shorting bar to short both control circuits together. Check the connectors and CPAs if a DTC with symptom byte 02 or 0E is set, to ensure the shorting bars are not causing the circuits to be shorted together. Shorting bars are used in the locations listed below:
| • | Steering wheel air bag assembly |
| • | Steering wheel air bag coil assembly |
| • | Inline harness connectors |
| • | Harness side of the SDM connector |
Terminal fretting or incorrectly seated connector can cause an open/high resistance condition. Check the circuit terminals for fretting or incorrectly seated connector if a DTC with symptom byte 04 or 0D is set.
If the driver steering wheel air bag has inflated under unexpected conditions and/or DTC with symptom byte 01 is set, check both control circuits for a short-circuit to voltage.
SIR System Description and Operation
Control Module References for scan tool information
Note: Refer to SIR Service Precautions .
Inspect all terminals for damage or corrosion when disconnecting connectors. Damage or corrosion in the following requires repair or replacement of the affected component/connector.| • | Steering Wheel Air bag |
| • | Steering wheel air bag coil |
| • | SDM |
| • | Air bag wiring harness connector |
| • | SDM wiring harness connector |
Note: The connector and connector position assurance (CPA) may seat independently 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.
If the condition is intermittent or cannot be duplicated, disconnect the connectors and add Nyogel lubricant 760G. This procedure will correct the high resistance condition due to terminal fretting corrosion.If less than 2.1 or greater than 4.0 Ω
Refer to Circuit/System Testing.
If there are spikes or dropouts
Replace the X85 driver steering wheel air bag coil.
If within 2.1 and 4.0 Ω without any spikes or dropouts
If the DTC is set as current
Refer to Circuit/System Testing.
If the DTC is set as history
| • | X85 Steering wheel air bag coil |
| • | F107 Steering wheel air bag. |
| • | Any inline harness connector |
| • | K36 SDM |
If the reading is erratic while moving the harness, perform the following
| • | Inspect each connector terminal for damage or corrosion and repair as necessary. |
| • | Apply Nyogel lubricant 760G to each connector terminal. |
| • | Insure each connector and CPA is correctly seated. |
If within 2.1 and 4.0 Ω without any spikes or dropouts
If 25 Ω or less
| 2.1. | Disconnect the X1 harness connector at the K36 SDM. |
| 2.2. | Test for infinite resistance between the two control circuits. |
If less than infinite resistance, repair the short between the two circuits.
If infinite resistance, replace the K36 SDM.
If greater than 25 Ω
| • | Control circuit terminal 1 |
| • | Control circuit terminal 2 |
If 11 V or greater
| 4.1. | Ignition OFF, disconnect the X1 harness connector at the K36 SDM, ignition ON. |
| 4.2. | Test for less than 1 V between the control circuit and ground. |
If 1 V or greater, repair the short to voltage on the circuit.
If less than 1 V, replace the K36 SDM.
If less than 11 V
| • | Control circuit terminal 1 |
| • | Control circuit terminal 2 |
If 25 Ω or less
| 6.1. | Disconnect the X1 harness connector at the K36 SDM. |
| 6.2. | Test for infinite resistance between the control circuit and ground. |
If less than infinite resistance, repair the short to ground on the circuit.
If infinite resistance, replace the K36 SDM.
If greater than 25 Ω
If the reading is erratic while turning the steering wheel
Replace the X85 steering wheel air bag coil.
If 2 Ω or greater
| 8.1. | Ignition OFF, disconnect the X1 harness connector at the K36 SDM. |
| 8.2. | Test for less than 2 Ω in the K85 steering wheel air bag coil and each control circuit end to end. |
If 2 Ω or greater, replace the coil or repair the open/high resistance in the circuit.
If less than 2 Ω, replace the K36 SDM.
If less than 2 Ω
Perform the Diagnostic Repair Verification after completing the repair.
| • | Control Module References for SDM replacement, programming and setup |
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