Code
P1199
JAGUAR
P — Powertrain
Fuel Level Input Circuit Low
Views:
UK: 47
EN: 55
RU: 36
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring between fuel level sender and ECU/BCM
- Corroded or loose connector at the fuel sender or ECU/BCM
- Failed or stuck fuel level sender (sending unit or float)
- Poor ground at sender or module
- Faulty instrument cluster, BCM, or PCM input circuit
- Water intrusion or contamination in the fuel tank connector/harness
Symptoms
- Incorrect or no fuel level reading on the dash gauge
- DTC P1199 stored and MIL may or may not be illuminated
- Intermittent fuel gauge operation (works after tapping or wiggling connector)
- Possible no-start is unlikely, but other body/BCM functions could be affected if shared circuits are damaged
What to check
- Read stored codes and freeze frame data with a scan tool; record fuel level sensor voltage or % if available
- Visually inspect fuel tank wiring harness, connector, and sender for damage, corrosion, or moisture
- Backprobe the fuel level input at the ECU/BCM and measure voltage with key ON (engine OFF)
- Disconnect the sender connector and measure resistance of the sender across its terminals while moving the float (observe smooth, continuous change)
- Check continuity and for short to ground between the sender signal wire and ground
- Check and verify proper ground at the sender and at the module grounds
Signal parameters
- Expected signal type: variable voltage or variable resistance from fuel level sender to module
- Typical voltage range: ~0.2–5.0 V (low = empty, high = full) — exact range depends on model
- A low input condition is usually indicated when the measured voltage is near 0 V or below the lower threshold expected by the controller
- Resistance of sender should vary smoothly across float travel (no open circuit or abrupt jumps)
Diagnostic algorithm
- Connect a diagnostic scanner and verify P1199 is current or historic; note freeze frame and live fuel level data.
- Inspect external wiring and connectors at the fuel tank/sender for corrosion, bent pins, water intrusion, or damage. Repair any visible issues and retest.
- With the ignition ON (engine OFF), backprobe the fuel level input pin at the ECU/BCM and measure voltage. If voltage is near 0 V, proceed to wiring checks.
- Disconnect the sender harness at the tank. Measure resistance of the sender across its terminals and operate the float; verify a smooth, continuous change in resistance. If open or erratic, replace sender assembly.
- Check continuity of the signal wire between the sender connector and the ECU/BCM input; check for short to ground or power. Repair any damaged wiring or harness chafing.
- Verify good ground(s) for the sender and related module grounds. Clean and tighten ground connections as needed.
- If wiring and sender test good, check the ECU/BCM input pin for damage and verify reference circuits (some systems use a reference voltage or pull‑up). Compare to factory pinout/schematic. If the module input is confirmed faulty, follow manufacturer procedure for module repair or replacement.
- Clear codes and confirm the repair by monitoring live data while refueling and road testing to ensure the fuel level reads correctly and P1199 does not return.
Likely causes
- Corroded/loose connector at the fuel sender or ground
- Short to ground in the sender wiring (pinched or chafed harness)
- Failed fuel level sending unit (open or low output)
- Faulty module input (less common) after wiring checks
Fault status
Status
Fuel Level Input Circuit Low — fuel level sender input voltage below expected threshold.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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