Code
B1515
ALFA ROMEO
B — Body
Driver seat occupied switch circuit
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring between the occupied switch and body control/SRS module
- Corroded, loose or disconnected connector under the driver seat
- Faulty driver seat occupied switch or sensor assembly
- Water ingress or debris at the seat connector or switch
- Aftermarket seat or repairs that altered wiring
- Faulty body control module / SRS module (less common)
Symptoms
- Seatbelt reminder chime/indicator behaves incorrectly for driver
- SRS/airbag warning lamp or seatbelt lamp may illuminate
- Occupant classification/seatbelt monitoring not detecting driver reliably
- Possible intermittent fault that changes with seat position or vibration
What to check
- Read freeze frame and live data with a diagnostic scanner to confirm B1515 and view signal state
- Visually inspect connectors and wiring under the driver seat for damage, corrosion, or loose pins
- Wiggle the seat harness while watching live data to reproduce an intermittent change
- Check related fuses and ground points for integrity
- Compare measured signal to expected values (see signal_params)
Signal parameters
- Reference voltage typically 5 V or battery voltage supplied to the seat switch circuit (manufacturer-specific)
- Closed/occupied switch: signal near ground or low resistance to ground (may read ~0–1 kΩ depending on sensor type)
- Open/unoccupied switch: signal high or open-circuit (infinite/very high resistance)
- Intermittent values or floating voltages indicate poor connection or broken conductor
Diagnostic algorithm
- Retrieve and record DTCs and freeze-frame data using a compatible scan tool; note vehicle state when fault occurred.
- Follow manufacturer procedure to disable SRS system power before working near seat wiring and airbags.
- Visually inspect the driver seat connectors, harness, and seat frame area for chafing, pinched wires, corrosion or moisture.
- With connector disconnected, inspect terminal condition and clean or repair corroded terminals; ensure connectors fully lock.
- Using a multimeter, check continuity between the occupied switch pins and the control module connector; check for shorts to ground or battery.
- Measure resistance of the occupied switch (if service manual gives values) or monitor signal voltage while someone sits/stands on the seat to verify state change.
- Wiggle test wiring with connectors connected while watching live data to locate intermittent faults caused by movement.
- If wiring and connectors are good but switch readings are out of specification, replace the driver seat occupied switch/sensor assembly.
- If replacement does not clear the issue, check the receiving module inputs and power/ground; consider module replacement only after wiring and sensor verified.
- Clear DTCs and perform road/seat tests to confirm the fault does not return.
Likely causes
- Wiring damage at the seat base (pinching by seat movement)
- Connector terminals pushed out or bent under the seat
- Failed occupant sensor within seat cushion (resistance/strain sensor)
- Contamination or corrosion in connector from spilled liquids
- Poor repair/installation after seat removal
Fault status
Status
Stored fault — driver seat occupied switch circuit open/short/intermittent. May affect seat occupant detection and related SRS/seatbelt functions. Inspect wiring, connector, and switch.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Repair manuals
Manual library for ALFA ROMEO
89
Browse 89 ALFA ROMEO manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
ALFA ROMEO
-
ALFA ROMEO: 2024
-
ALFA ROMEO: 2023
-
Stelvio
-
ALFA ROMEO: 2022
-
Stelvio
-
ALFA ROMEO: 2021
-
Stelvio
-
ALFA ROMEO: 2020
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email