B1802 on Toyota: How to Diagnose & Fix
Lamp Turn Signal Rear Output Circuit (manufacturer-specific)
1 Toyota model · 1 documented issue · $350-$900 repair
B1802 on Toyota by model: symptoms, diagnosis and fix
A common problem on 10th-generation Corolla models is failure of the steering wheel spiral cable, also called the clock spring. When the ribbon circuit inside the cable breaks, the SRS warning light illuminates and steering-wheel-mounted functions such as the horn or audio switches may stop working. Toyota issued a warranty enhancement and many owners also documented the issue through NHTSA complaints and forum reports.
Common Symptoms
- airbag warning light on
- horn inoperative
- steering wheel audio/cruise buttons stop working
- intermittent SRS light
- airbag system fault stored
How to Fix
Diagnosis usually starts by scanning the airbag system for driver-side squib or spiral cable communication faults, then checking whether the horn and steering wheel buttons also fail intermittently. Repair is replacement of the spiral cable assembly and clearing SRS codes; care is required because the airbag module must be removed and the replacement part must be centered correctly before installation.
Sources for this issue (1)
B1802 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does B1802 mean on a Toyota?
B1802 stands for "Lamp Turn Signal Rear Output Circuit (manufacturer-specific)." B1802 is a manufacturer-specific body code, associated mainly with Ford-family lighting systems, that generally indicates a fault in the rear turn-signal lamp output circuit detected by the lighting/body control module. Because it is manufacturer-specific, the precise wording and fault type (open, short, or failure) can vary by make and model and should be confirmed against the vehicle's service information. The practical effect is typically an inoperative or improperly functioning rear turn signal. On Toyota it is documented across 1 model: Corolla.
What are the most common causes of B1802?
The most common causes of B1802 are: Fault (short or open) in the rear turn-signal wiring, Faulty rear turn-signal bulb, Corroded or damaged bulb socket/connector, Chafed or pinched rear harness, Water intrusion in the rear lamp assembly, Internal fault in the lighting/body control module. The specific cause varies by vehicle.
How much does it cost to fix B1802 on a Toyota?
Published repair estimates on Toyota range from $350 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for B1802 on a different make?
View B1802 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.