B1212 code definition
The B1212 indicates that a related control module has detected that the Switch 2 assembly circuit in the dashboard electronic instrument cluster (EIC) has been shorted.
What the B1212 code means
Some modern vehicles have an EIC, which is an electronic equivalent to analog dashboard indicators. In the case of a shorted circuit, a much higher than usual burst of electricity will surge through the circuit, potentially damaging fuses and wiring.
What causes the B1212 code?
A B1212 code is typically the result of wiring issues related to the EIC's Switch 2 assembly circuit. Electrical connectors and wiring alike may be corroded, disconnected, or damaged due to external forces, such as damage from liquids. Blown fuses often accompany a B1212 code. Although blown fuses may not account for the initial registered code, they will need to be repaired accordingly before the code is properly resolved.
What are the symptoms of the B1212 code?
The electronic dashboard will typically be disabled or act erratically in the case of a verified B1212 scenario. Blown fuses may cause other related systems to fail as well. For the sake of diagnosing the problem, the vehicle computer will log a B1212 trouble code. Although an illuminated trouble indicator request may be sent to the dashboard, if the EIC is compromised it is not likely that it will go through.
How does a mechanic diagnose the B1212 code?
A mechanic can diagnose the B1212 trouble code by inputting the vehicle computer with an OBD-II code reader. A voltmeter or Autohex scanner can be used to pinpoint the source of the short damage along the circuit. In addition, any fuses or components related to the shorted circuit should be examined for signs of damage caused from the overload.
For safety reasons, all shorted wiring should be handled with the power off.
Common mistakes when diagnosing the B1212 code
Blown fuses often accompany a shorted circuit. Blown fuses may be overlooked as a secondary cause of the B1212 issue.
How serious is the B1212 code?
Because the B1212 code compromises the EIC, all dashboard data, including the speedometer, may be disabled. Although this technically doesn't affect the vehicle's drivability, not knowing your vehicle's speed or fuel level is not preferable if driving. It is strongly recommended that this issue be fixed before taking the vehicle to the road.
What repairs can fix the B1212 code?
The wiring related to the electronic instrument cluster should be thoroughly examined with the fuse power off. Any disconnected, corroded, broken or damaged wiring should be repaired or replaced accordingly. Any fuses or components that were blown during the short circuit should be replaced as necessary. Following repairs for the B1212 code, the vehicle should be started up to see if the EIC will light up properly.
Additional comments for consideration regarding the B1212 code
The vehicle's manual may offer more specific guidance on how to address a B1212 trouble code.
Need help with a B1212 code?
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.
This article originally appeared on YourMechanic.com as B1212 OBD-II Trouble Code: EIC Switch-2 Assembly Circuit Short To Ground and was authored by Conor Fynes.