B1202

Code

FIAT B — Body

Fuel level sender circuit open

Brand: FIAT

Type: B — Body

Views: UK: 2 EN: 21 RU: 5

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or broken wiring between fuel level sender and instrument/body control module
Corroded or loose connector at sender or module
Failed fuel level sender (float, rheostat) inside fuel pump module
Poor ground at sender or module
Water intrusion or corrosion inside sender connector or pump module
Faulty instrument cluster or body control module (less common)

Symptoms

Fuel gauge reads full, empty, or unpredictable/jumping values
Instrument cluster displays fuel level fault or message
No fuel level information available to ECU/cluster (affects range calculations)
Possible malfunction indicator or warning lamp related to body systems (not always MIL)

What to check

Visual inspection of wiring and connectors at fuel pump module and instrument/body control module
Scan vehicle for stored/active related codes and freeze frame data
Observe fuel level reading from scan tool with key ON engine OFF and while moving float (if accessible)
Backprobe connector at pump/sender to measure signal and reference voltage
Measure resistance of sender with sender removed (compare to specification)
Check ground continuity from sender ground terminal to chassis ground

Signal parameters

Reference supply voltage: typically 5 V (vehicle dependent) present at sender reference pin with ignition ON
Signal voltage: typically 0.5–4.5 V proportional to tank level (0 V or open circuit indicates fault)
Sender resistance (typical): varies by model — commonly 0–300 ohms or 240–30 ohms from empty to full; consult vehicle-specific service data
Open-circuit: infinite/OL resistance between sender signal and reference or ground

Diagnostic algorithm

Read and record all stored DTCs with a compatible scan tool and note freeze frame data
Visually inspect the fuel pump/sender connector and wiring for damage, corrosion, or water ingress
With ignition ON (engine OFF) backprobe the reference pin at the sender connector and verify the reference voltage (usually ~5 V) from the module
Backprobe the sender signal pin and observe voltage on the scan tool/live data; note value and whether it changes when float is moved (if accessible)
If signal is open/0 V, disconnect connector and measure resistance across sender terminals at the pump module; compare to spec — infinite resistance indicates open sender
Check continuity between sender connector signal pin and the instrument/body control module input pin; repair any open or high-resistance sections
Check sender ground continuity to chassis ground; repair poor ground connections
If wiring and connectors are good but sender resistance is out of spec or open, remove and replace sender or pump module as required
After repair, clear codes and verify proper gauge operation and no return of B1202; road test and re-scan to confirm

Likely causes

Broken wire in harness (chafing, pinched, connector detached)
Corroded connector pins at fuel pump/sender or module
Failed sender rheostat or broken float arm inside fuel tank
Bad ground or power reference to the sender
Connector pushed out of pump assembly or damaged during service

Fault status

⚠️ Status

Control module detected an open or interrupted circuit on the fuel level sender input. The module cannot reliably read tank level from the sender and has logged a circuit open fault.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2 hours

Similar codes

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