B1219

Code

Other B — Body

Fuel Tank Pressure Sensor Circuit Failure

Brand: Other

Type: B — Body

Views: UK: 27 EN: 51 RU: 30

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Open or shorted signal/ground/reference wiring between sensor and control module
Corroded, loose, or damaged sensor connector
Failed fuel tank pressure / EVAP pressure sensor
Water/contamination in connector or sensor
Poor sensor reference voltage or ground at the module
Module (ECU/BCM) input circuit fault

Read stored/freeze‑frame data and confirm B1219 and any related EVAP codes
Visual inspection of sensor, connector, and wiring at fuel tank for damage, corrosion, or water
Scan tool: monitor live sensor voltage/data while key ON, engine OFF and while applying vacuum/pressure if possible
Backprobe connector to verify reference voltage, signal voltage, and ground
Check continuity and resistance of signal, reference, and ground wires from sensor connector to module
Wiggle test wiring and monitor for intermittent changes

Reference supply typically ~5.0 V (check vehicle spec)
Sensor output range typically ~0.1–4.9 V (vehicle dependent)
Atmospheric/neutral pressure commonly near mid‑scale (~2.5 V) on many systems
Under vacuum signal usually decreases toward lower voltages; under positive pressure it increases
Expect smooth, monotonic change in voltage when applying vacuum/pressure (no erratic spikes)

Confirm code and note freeze‑frame/related codes (EVAP codes like P0455/P0456 common companions).
Perform visual inspection at tank: connector seated, pins straight, no corrosion/water, wiring not chafed.
With ignition ON (engine OFF) backprobe connector: verify ~5V reference between reference pin and ground; verify good ground (near 0V). If reference or ground missing, trace and repair wiring/fuse/connector.
Measure sensor signal voltage with connector connected at atmospheric pressure (expect near mid‑scale). Wiggle harness to check for intermittent changes.
Check continuity/resistance of signal, reference and ground wires from sensor to module with connector disconnected. Look for opens or shorts to chassis/power.
Apply a controlled vacuum/pressure to the sensor (service tool) and confirm the output voltage changes smoothly and proportionally. If signal does not respond, suspect sensor defect.
If wiring tests good but signal still bad, swap in a known‑good sensor (if available) or replace sensor and retest.
If replacement sensor does not restore correct signal and wiring tests are good, inspect/diagnose module input circuit and related fuses; consider module repair/reprogramming per manufacturer procedures.
After repair clear codes and perform drive cycle or EVAP system test to confirm the issue is resolved.

Wiring or connector fault at tank sensor (broken wire, corrosion, crushed harness)
Sensor element failed (internal short or open)
Intermittent connection from vibration or movement
Faulty reference 5V supply or ground at the control module