B0020
DTC B0019 or B0020
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 B0019 01
- Passenger Instrument Panel Air Bag Deployment Loop Stage 1 Short to Battery
DTC B0019 02
- Passenger Instrument Panel Air Bag Deployment Loop Stage 1 Short to Ground
DTC B0019 08
- Passenger Instrument Panel Air Bag Deployment Loop Stage 1 Signal Invalid
DTC B0019 0D
- Passenger Instrument Panel Air Bag Deployment Loop Stage 1 High Resistance
DTC B0019 0E
- Passenger Instrument Panel Air Bag Deployment Loop Stage 1 Low Resistance
DTC B0020 01
- Passenger Instrument Panel Air Bag Deployment Loop Stage 2 Short to Battery
DTC B0020 02
- Passenger Instrument Panel Air Bag Deployment Loop Stage 2 Short to Ground
DTC B0020 08
- Passenger Instrument Panel Air Bag Deployment Loop Stage 2 Signal Invalid
DTC B0020 0D
- Passenger Instrument Panel Air Bag Deployment Loop Stage 2 High Resistance
DTC B0020 0E
- Passenger Instrument Panel Air Bag Deployment Loop Stage 2 Low Resistance
Diagnostic Fault Information
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 an air bag or pretensioner. There are 2 shorting bars which will short together control circuits, when the connector is disconnected. This will help to prevent unwanted deployment of the air bag or pretensioner during servicing.
Conditions for Running the DTC
Ignition voltage is between 9-16 V.
Conditions for Setting the DTC
B0019 01, B0020 01
The air bag control circuit is shorted to voltage for 2 seconds.
B0019 02, B0020 02
The air bag control circuit is shorted to ground for 2 seconds.
B0019 08, B0020 08
The air bag control circuit is open for 2 seconds.
B0019 0D, B0020 0D
The air bag deployment loop resistance is greater than 4.2 ohms for 2 seconds.
B0019 0E, B0020 0E
The air bag deployment loop resistance is less than 1.4 ohms for 2 seconds.
Action Taken When the DTC Sets
* 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 deployments.
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.
Diagnostic Aid
Note: The following diagnostic aids apply for both current and history DTCs.
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:
* Passenger instrument panel air bag
* Inline harness connectors
* Harness side of the SDM connector
Terminal fretting or incorrectly seated connectors 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. DTCs of deployment loops which are in the seat can occur because of stress or damage to the harness due to seat movement. Move the seat to the full extent of travel while using the scan tool to observe deployment type loop parameters.
Reference Information
Schematic Reference
SIR Schematics [1][2]Air Bag Systems
Connector End View Reference
Component Connector End Views Sunshade - Left (DH6)
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 Control Module References for scan tool information
Special Tools
EL-38125-580 - Terminal Release Tool Kit
Circuit/System Verification
Note: Refer to SIR Service Precautions Technician Safety Information.
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.
* Seat belt buckle pretensioner
* Passenger instrument panel air bag
* Seat side air bag
* Roof rail air bag
* SDM
* Seat belt retractor pretensioner wiring harness connector
* Passenger instrument panel air bag wiring harness connector
* Seat side air bag wiring harness connector
* Roof rail air bag wiring harness connector
* SDM wiring harness connector
Note: 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. 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.
1. Verify the appropriate scan tool Deployment Loop Resistance parameters stay consistently between 2.1 and 4.0 ohms without any spikes or dropouts while moving the harness near each connector listed below:
* F105 passenger instrument panel air bag
* Any inline harness connector
* K36 SDM
• If less than 2.1 or greater than 4.0 ohms
Refer to Circuit/System Testing.
• If there are spikes or dropouts, perform the following
* Inspect each connector terminal and harness 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 ohms without any spikes or dropouts
2. All OK
Circuit/System Testing
1. Ignition OFF. Scan tool disconnected. It may take up to 2 minutes for all vehicle systems to power down. Disconnect the F105 passenger instrument panel air bag inline harness connector X254.
2. Test for greater than 25 ohms between the appropriate control circuit terminals listed below on the K36 SDM side of the connector:
* F105 passenger instrument panel stage 1 X254 terminal A1 and A2
* F105 passenger instrument panel stage 2 X254 terminal B1 and B2
• If 25 ohms or less
1. Disconnect the X2 harness connector at the K36 SDM.
Note: Some connectors may be equipped with shorting bars as a safety component to prevent accidental inflator deployment. When testing on a connector with shorting bars, the shorting bars must be disabled to ensure accurate test results. Insert an appropriate pick from EL-38125-580 and depress the shorting bars above the appropriate terminals. This will lift the shorting bar from the terminal and allow accurate test results. Take care not to damage the connector, shorting bar, or terminal when depressing the shorting bar.
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 ohms
3. Ignition ON.
4. Test for less than 11 V between the control circuit terminals listed below and ground:
* X254 control circuit terminal A1
* X254 control circuit terminal A2
* X254 control circuit terminal B1
* X254 control circuit terminal B2
• If 11 V or greater
1. Ignition OFF. Disconnect the X2 harness connector at the K36 SDM. Ignition ON.
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
5. Ignition OFF. Test for greater than 25 ohms between the control circuit terminals listed below and ground:
* X254 control circuit terminal A1
* X254 control circuit terminal A2
* X254 control circuit terminal B1
* X254 control circuit terminal B2
• If 25 ohms or less
1. Disconnect the X2 harness connector at the K36 SDM.
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 ohms
6. Install a 3 A fused jumper wire between the control circuit terminals listed below:
* F105 passenger instrument panel air bag stage 1 X254 terminal A1 and A2
* F105 passenger instrument panel air bag stage 2 X254 terminal B1 and B2
7. Ignition ON.
8. Verify the scan tool Deployment Loop Resistance parameter is less than 2 ohms.
• If 2 ohms or greater
1. Ignition OFF. Disconnect the X2 harness connector at the K36 SDM.
2. Test for less than 2 ohms in each control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K36 SDM.
• If less than 2 ohms
9. Ignition OFF. Reconnect the inline harness connector X254. Disconnect the F105 passenger instrument panel air bag harness connector. Ignition ON.
10. Test for less than 11 V between the control circuit terminals listed below and ground:
* F105 passenger instrument panel air bag control circuit terminal 1
* F105 passenger instrument panel air bag control circuit terminal 2
* F105 passenger instrument panel air bag control circuit terminal 4
* F105 passenger instrument panel air bag control circuit terminal 5
• If 11 V or greater
Repair the short to voltage on the circuit.
• If less than 11 V
11. Ignition OFF.
12. Test for greater than 25 ohms between the control circuit terminals listed below and ground:
* F105 passenger instrument panel air bag control circuit terminal 1
* F105 passenger instrument panel air bag control circuit terminal 2
* F105 passenger instrument panel air bag control circuit terminal 4
* F105 passenger instrument panel air bag control circuit terminal 5
• If 25 ohms or less
Repair the short to ground on the circuit.
• If greater than 25 ohms
13. Install a 3 A fused jumper wire between the control circuit terminals listed below:
* F105 passenger instrument panel air bag stage 1 X254 terminal A1 and A2
* F105 passenger instrument panel air bag stage 2 X254 terminal B1 and B2
14. Ignition ON.
15. Verify the scan tool Deployment Loop Resistance parameter is less than 2 ohms.
• If greater than 2 ohms
Repair the open/high resistance in the circuit between the F105 passenger instrument panel air bag connector and the X254 inline harness connector.
• If less than 2 ohms
16. Ignition OFF, connect the harness connector at the F105 passenger instrument panel air bag, press in the CPA (if equipped) until an audible and/or tactile click is heard.
17. Ignition ON, clear DTCs. Operate the vehicle within the Conditions for Running the DTC.
18. Verify DTC B0019 or B0020 is not set.
• If DTC B0019 or B0020 is set
Replace the F105 passenger instrument panel air bag.
• If DTC B0019 or B0020 is not set
19. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Instrument Panel Airbag Replacement Instrument Panel Airbag Replacement
* SIR/SRS Wiring Repairs SIR/SRS Wiring Repairs
* Control Module References Control Module References for SDM replacement, programming and setup