Skip the auto shop - Our mechanics make house calls

B1203 OBD-II Trouble Code: Fuel Sender Circuit Short To Battery

diagnostic check engine light

B1203 code definition

A B1203 diagnostic trouble code indicates that the fuel tank sender circuit has shorted.

What the B1203 code means

The fuel sender uses varying levels of voltage to gauge the vehicle's fuel levels. The insulation for the fuel sender may be faulty or wear to the point where electrical currents cross, resulting in a shorted circuit. This damage will make it impossible for the fuel sender to report accurate fuel levels to the dashboard panel.

What causes the B1203 code?

A B1203 code shorted circuit is usually a result from a fault in the wiring insulation. The fuel sender itself may also be defective.

What are the symptoms of the B1203 code?

In the case of a B1203 code, the fuel gauge may read as empty, regardless of the amount of fuel currently in the tank. The fuel gauge may also read as full regardless of fuel intake.

In addition, for the purpose of diagnosing the issue, the vehicle's onboard computer will log a B1203 code and the dashboard trouble light will be illuminated.

How does a mechanic diagnose the B1203 code?

A mechanic can first diagnose the B1203 code by reading the vehicle's computer with an OBD-II code scanner. The actual tank level may be checked with a dipstick. The fuel sender itself should be examined for signs of fault. All wiring and circuitry relating to the fuel sender unit should be thoroughly inspected for signs of damage.

Common mistakes when diagnosing the B1203 code

The tank should be inspected with the battery leads removed first, as fuel vapour is extremely flammable and a live battery may prove a risk.

How serious is the B1203 code?

A malfunctioning fuel sender will likely render the vehicle's fuel gauge inoperable. This code should be taken seriously and repaired as soon as is possible.

What repairs can fix the B1203 code?

Drain the fuel tank before attempting any repairs. Below are fixes that should resolve the B1203 code:

  • Repairing or replacing faulty or damaged wires
  • Refitting or replacing the fuel sender

Additional comments for consideration regarding the B1203 code

Body-related trouble codes are specific to particular models of vehicle. The meaning of a B Class trouble code will depend on the make and manufacturer. Refer to the vehicle manual if you're unclear on whether a given code description pertains to your model.

Need help with a B1203 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222 code means The manufacturer specifies a range of acceptable voltage to be produced from the throttle position...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....
How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...


Related questions

Q: 3 warning lights on, power steering, VMS, and electronic lights. Any clue?

The fact that these lights are on is a warning to the driver that there are fault codes stored because one of more control systems have detected a problem. The vehicle will have to be read with a code scanner...

Q: OBD-II failed for smog check

Unfortunately without more information as to why your Toyota Corolla did not pass the emissions test, it is difficult to determine the cause for the failed smog check. Provided that the ODB2 port itself has power and is allowing the...

Q: Check Engine Light is on - 2012 Nissan Xterra

Anytime a code is stored, it will stay stored and the Check Engine Light will stay on until the ECM memory is cleared. If the problem is fixed, then the light and code should not come back. Many times a...