B1992 code definition
A B1992 trouble code is stored by the Powertrain Control Module (PCM) after it receives a voltage signal from the side mount air bag circuit that falls out of the range signified by the manufacturer's specifications. Some related codes that a mechanic might also find stored in addition to the B1992 trouble code include a B1993, B1994, B1995, B1996, B1997, B1998, and B1999 code.
What the B1992 code means
The storage of a B1992 trouble code by the PCM means that the voltage from the side mount air bag circuit is higher or lower than the parameters set by the vehicle manufacturer. Subsequently, the Supplemental Restraint System (SRS) light will come on when the B1992 trouble code is stored. Also, in most vehicles, the SRS is disabled, including the air bags not deploying or the seatbelts not tightening as they should.
What causes the B1992 code?
Some common causes of a B1992 trouble code include loose or bad wiring, a fault with the ground wire, or a fault within the air bag itself. A mechanic should keep in mind that having to disconnect the battery also causes the SRS system to reset. And, in some cases, this action might require a mechanic to reprogram the control module associated with the air bag system. The air bag system may be prevented from working until this step is performed.
What are the symptoms of the B1992 code?
Probably the only indicator of a bad driver side air bag is the storage of the relevant code and the illumination of the SRS warning light. In instances where the light does not work properly, the PCM will indicate a problem by initiating a series of audible tones that sound while driving.
How does a mechanic diagnose the B1992 code?
To safely diagnose trouble codes stored in response to a problem with a vehicle's air bag system, a mechanic needs to use an advanced scanner and a digital multimeter with its output set at 10 mA or less. This is to prevent any damage to the air bag system, or even possibly the deployment of the air bag, while diagnosing the issue. In addition to these safety precautions, the mechanic should also perform the following diagnostic steps:
- The mechanic should start by clearing the code and retesting the system to see if the code returns.
- To test the vehicle air bag system, the mechanic should start the vehicle and shake the wire harness and connectors to see if there are any loose connections or shorts.
- The mechanic should also take the vehicle for a test drive to see if the code is stored again, usually signified by the illumination of the SRS Warning Light.
- If the code is not stored again, the mechanic should download any stored trouble codes and freeze frame data.
- Next, after properly disconnecting both battery cables, the mechanic should inspect any wiring, connectors, or components in the wiring harness.
- The mechanic should also inspect the battery to make sure it is carrying a full charge. They should also check the battery cable terminals for corrosion.
- After replacing any bad or faulty wiring or connectors, they should clear the code, reconnect the battery cables, reprogram the control modules associated with the air bag system, if necessary, and retest the system to see if the trouble code returns.
- If the code returns, the mechanic should check should test the voltage and ground signal of the driver side air bag circuit.
- If no signal or voltage are detected, the mechanic should disconnect the PCM and any related control modules before testing the continuity of the circuit with the battery ground.
- The mechanic should also test the continuity between the PCM and any related control modules.
- Finally, they should clear the code and retest the system to see if the B1992 trouble code returns.
Common mistakes when diagnosing the B1992 code
A common mistake made with a B1992 trouble code is for a mechanic to overlook simple fixes, such as a loose connection or poorly charged battery, and to replace more expensive components. The result is the problem remains and the code returns.
How serious is the B1992 code?
A B1992 trouble code is very serious as it can affect the safety of the vehicle occupants. As such, a vehicle owner should have a mechanic diagnose and fix the trouble code as soon as possible to prevent injury or death from an accident.
What repairs can fix the B1992 code?
To repair and clear a B1992 trouble code, a mechanic needs to perform the following:
- Replace any damaged or faulting wiring, connectors, and components. The mechanic must also check to make sure that all wiring and connectors are tightly secured.
- Install a new battery if the old one is bad.
- The mechanic should also clean the battery cable connectors of any corrosion, replacing the clamps if necessary.
- Replace the driver's side air bag if the component tests as faulty.
- Replace any air bag control module that tests as faulty.
Additional comments for consideration regarding the B1992 code
When diagnosing a vehicle's air bag system, it is important that the mechanic disconnect both battery cables first to prevent accidental deployment of the air bag. In addition, the mechanic should wait at least three minutes before proceeding after disconnecting the battery cables. During this three-minute time span, it is still possible for the air bag and the seat belt pre-tensioner to deploy.
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