B1203

Code

ALFA ROMEO B — Body

Fuel level sender circuit fault

Brand: ALFA ROMEO

Type: B — Body

Views: UK: 7 EN: 14 RU: 8

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Page language: EN

Open or short in fuel level sender wiring (broken wire, chafing, pinched harness)
Corroded or loose connector at the sender or instrument cluster/ECU
Failed fuel level sender (float/potentiometer or tank module)
Poor or missing ground for the sender circuit
Faulty instrument cluster or body control module input
Water/contamination or mechanical binding of the float

Retrieve freeze frame and live data with a diagnostic tool — note fuel level reading and related parameters
Check battery voltage and stabilise to rule out low-voltage related faults
Visual inspection of wiring and connectors at the fuel tank access point and instrument cluster
Check fuses and module grounds related to the instrument cluster/BCM
Wiggle harness while observing live fuel-level signal for intermittent faults
Measure sender resistance and/or voltage while moving the float (with tank access)

Typical sender resistance varies by model — many senders read roughly 0–90 Ω or 10–180 Ω between empty and full (consult factory manual for exact values)
Typical sender supply/reference voltage: approx. 5 V (or vehicle-specific reference from BCM/cluster)
Typical sender signal voltage range: approx. 0.5–4.5 V across float travel (confirm with service data)
Open-circuit: infinite resistance or no signal; Short-to-ground: near 0 V; Short-to-Vref: near reference voltage
Measure resistance while moving float to verify smooth, continuous change (no abrupt jumps)

Verify trouble code(s) and record live fuel level readings and related data with scan tool. Note whether the fault is permanent or intermittent.
Check battery voltage and grounds. Ensure stable supply voltage to modules before testing the sender.
Visually inspect and test connectors at the fuel tank module and instrument cluster/BCM for corrosion, bent pins, or water intrusion. Repair or clean as needed.
Back-probe the sender signal and reference pins at the tank connector. With ignition ON, verify reference voltage present and measure signal voltage while moving the float (or gently moving sender arm).
With harness disconnected, measure sender resistance across its terminals while moving the float. Compare to factory specification; look for smooth resistance change without open/short jumps.
Perform continuity and short checks on wiring from the tank connector to the cluster/BCM: check for short-to-ground, short-to-Vref, and open circuits.
Wiggle test the harness and connectors while observing live data to reproduce intermittent behavior. If intermittent, localise and repair wiring or connector.
If wiring and connectors are good and sender resistance/voltage out of spec, replace the fuel level sender or tank module. If sender OK, consider instrument cluster/BCM input fault and test/replace per manufacturer procedure.
After repair, clear DTCs and confirm proper operation via live data and road test. Re-scan for return of code.

⚠️ Status

Fuel level sender circuit fault detected. Signal open/short or out-of-range — inspect sender, wiring, connector, and module inputs.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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