B1998 code definition
The B1998 trouble code notes a side mount air bag circuit error on the passenger side.
What the B1998 code means
The B1998 code is a generic OBD-II trouble code that detects an air bag circuit problem in the side-mount air bag on the passenger side of the vehicle. The side mount air bag is responsible for protecting the side of the occupant in the front passenger seat, and is located on the passenger side B-pillar. If the vehicle is in a collision, the side mount air bag deploys into the passenger, to provide protection. Whenever a circuit malfunction from the side mount air bag on the passenger side is noted by the air bag control module, body control module, or powertrain control module (PCM), the B1998 trouble code may be detected.
What causes the B1998 code?
By far the most common cause of the B1998 trouble code is damaged electrical components. Usually this means shorted wires in the circuit, but blown fuses and loose connectors can also be the culprit. These damaged electrical parts may be in the side mount air bag circuit, the clockspring, or possibly the air bag control module. It is also fairly common for the B1998 code to be triggered by a defective clockspring, or a malfunctioning side mount air bag system. The code can also be stored due to a failed air bag control module, though this is rare, or due to a defective PCM or body control module, though this is very rare.
What are the symptoms of the B1998 code?
When the B1998 trouble code is detected, the air bag system will not function properly. Should an accident occur, the side mount air bag on the passenger side will almost surely fail to deploy. It is also quite possible that all of the air bags will fail, leaving the vehicle devoid of a critical safety feature. The code is often accompanied by an illuminated check engine soon Warning Light, or the air bag Warning Light.
How does a mechanic diagnose the B1998 code?
The B1998 trouble code should be diagnosed with a standard OBD-II trouble code scanner. A certified technician will use the scanner to view the freeze frame data and gather information about the code. Additional trouble codes will also be checked for, and, if detected, should be diagnosed in the order that the scanner displays them in. The codes will then be reset, the vehicle restarted, and the B1998 code checked for again. If the code is no longer present, then an intermittent issue or an erroneous detection are likely to blame.
If the code is still detected, then the mechanic will visually inspect the electrical components in the side mount air bag system, and replace any fuses, wires, or connectors that have been damaged or otherwise compromised. Next, the technician will inspect the clockspring, and the side mount air bag system. The air bag control module should then be tested.
After any replacements or repairs are made, the trouble codes will again be reset, the vehicle again restarted, and the B1998 code once more checked for. By doing this, the technician will know as soon as the issue has been fixed.
Common mistakes when diagnosing the B1998 code
The most common error when diagnosing this code is the failure to observe the OBD-II trouble code diagnosis protocol. It is highly important that mechanics abide by the protocol at all times, as it helps guarantee accurate and efficient inspections.
Side mount air bag systems and clocksprings are often inaccurately condemned, because failed electrical components were overlooked.
How serious is the B1998 code?
A vehicle with the B1998 code will still be drivable, and will not have any drivability issues. However, the air bag system will probably not function properly, which at best means the side mount air bag on the passenger side will not deploy, and at worst means all of the air bags will be inoperable. Because air bags are one of the most vital safety features that frequently save lives, the car should not be driven until an inspection and repair have been performed.
What repairs can fix the B1998 code?
Possible repairs for the B1998 trouble code are:
- Replacement of wires, connectors, or fuses
- Replacement of the side mount air bag system
- Replacement of the clockspring
- In rare cases, replacement of the air bag control module
- In very rare cases, replacement of the PCM or body control module
Additional comments for consideration regarding the B1998 code
This code is a manufacturer specific trouble code. A manufacturer specific code is one that has a varying definition depending on the automaker. The B1998 trouble code suggests a side mount air bag circuit failure in some cars, but detects a very different body issue in many other vehicles. It is important that the mechanic always be aware of the vehicle that is being worked on when diagnosing this code.
Need help with a B1998 code?
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This article originally appeared on YourMechanic.com as B1998 OBD-II Trouble Code: Passenger Side Side-Mount Air Bag Circuit Open and was authored by Brady Klopfer.