B1996 code definition
The Powertrain Control Module (PCM) stores a B1996 trouble code when a problem is detected with the passenger side side-mount air bag circuit. Codes stored in conjunction with this code include a B1992, B1993, B1994, B1995, B1997, B1998, and B1999 code.
What the B1996 code means
When the voltage from the passenger side side-mount air bag circuit is higher or lower than that specified by the manufacturer, a B1996 trouble code is stored by the PCM. In addition, the Supplemental Restraint System (SRS) warning light comes on.
What causes the B1996 code?
Most commonly, a B1996 trouble code is caused by loose or faulty wiring or connectors. Some additional causes include a fault with the ground wire, the air bag, or the battery.
What are the symptoms of the B1996 code?
The most common sign of a B1996 trouble code is an illuminated SRS warning light. If for some reason the SRS warning light is not operating properly, the PCM notifies the driver though a series of audible tones that sound while the vehicle is in operation.
How does a mechanic diagnose the B1996 code?
To diagnose a B1996 trouble code, a mechanic needs an advanced scanner, digital volt/ohm meter, and a passenger side side-mount air bag wiring harness schematic. In addition, the mechanic must complete the following steps:
Clear the code and test the system first to see if it returns.
If the code returns, download all freeze frame data, and then start the vehicle.
Test the wiring, connectors, and components in the passenger side side-mount air bag wiring harness for looseness or fault by shaking the wiring harness. The mechanic should use a passenger side side-mount air bag wiring harness schematic to help them with this process.
The mechanic should take the vehicle for a test drive to see if they can recreate the conditions that caused the code storage. While driving, they should make sure to turn the steering wheel from stop to stop.
The mechanic should also disconnect both battery cables before physically inspecting the air bag device. The mechanic should wait at least three minutes after disconnecting the battery to make sure the air bag is totally disarmed.
While disconnected, the mechanic should check both the battery, to see if it is still good, and the battery cable connectors, looking for corrosion or damage. They should also look for corrosion on the battery posts.
They should then reconnect the battery, with the ignition turned to the on position, reprogram the air bag control module if needed, and test the system again to see if the code returns.
If the B1996 trouble code returns, the mechanic should use a digital volt/ohm meter, set to an output of 10 mA or less, to test the reference voltage and ground signal between the passenger side side-mount air bag circuit and the PCM while using a wiring harness schematic.
If no reference voltage or ground signal is detected, the mechanic should disconnect the PCM and the related control modules and check the continuity of the passenger side side-mount air bag circuit with the battery ground.
They should also test the continuity of the air bag control module with the PCM.
Finally, they must clear the B1996 trouble code and retest the system to see if the code returns again.
Common mistakes when diagnosing the B1996 code
One common mistake made by mechanics diagnosing a B1996 trouble code is to assume the air bag mechanism is bad, when in actuality the problem is caused by bad wiring or even a loose connection. The mechanic must fully diagnose all wiring, connectors, and components before proceeding with their diagnosis to make sure the problem does not lie there. Failure to do so can lead to the problem remaining and further trouble code storage by the PCM.
How serious is the B1996 code?
When a B1996 trouble code is stored, the PCM also turns off the SRS system. This could lead to injury or death if an accident happens. That is why it is of utmost importance to get a B1996 trouble code diagnosed and fixed as soon as possible.
What repairs can fix the B1996 code?
To repair a B1996 trouble code, a mechanic must perform the following:
Replace any damaged or faulty wiring, connectors, or components in the passenger side side-mount air bag wiring harness. The mechanic should also test the wiring and connectors in the harness for looseness.
The next step is to install a new battery if necessary.
Then, clean or replace the battery cable connectors if corroded or damaged. In addition, if they are using the old battery, they should clean the posts if they are corroded.
Next, replace the passenger side side-mount air bag circuit if it is bad.
Replace the passenger side side-mount air bag if it is not working properly.
Replace the air bag control module if it is bad.
Additional comments for consideration regarding the B1996 code
Before physically inspecting the passenger side side-mount air bag, the mechanic must first disconnect both battery cables with the ignition on and wait three minutes before proceeding. This keeps the air bag from activating and potentially injuring the mechanic.
Need help with a B1996 code?
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This article originally appeared on YourMechanic.com as B1996 OBD-II Trouble Code: Passenger Side Side-Mount Air Bag Circuit Short to Vbatt and was authored by Cheryl Knight.