Code
B1219
ALFA ROMEO
B — Body
Fuel tank pressure sensor circuit
Views:
UK: 7
EN: 8
RU: 6
AI status
Completed
Completed
100%
Causes
- Open or short in fuel tank pressure sensor wiring or connector
- Corroded or loose connector pins at sensor or module
- Failed/contaminated fuel tank pressure (EVAP) sensor
- Poor sensor reference/ground (5V reference missing or unstable)
- Mechanical damage or blockage in EVAP lines or sensor port
- Intermittent wiring fault caused by chafing or water ingress
Symptoms
- Malfunction Indicator Lamp (MIL) or warning light illuminated
- Evaporative emission (EVAP) system fault messages
- Difficulty refueling or fuel tank venting issues (slow fill/halts)
- Fuel odor near tank or filler
- Failed emissions or EVAP leak test during inspection
- Occasional or constant DTC present depending on fault type
What to check
- Read DTCs and freeze frame data with a scan tool; record present/previous codes and long/short term fuel trims
- Visually inspect fuel tank pressure sensor connector and wiring for damage, corrosion, water, or poor sealing
- Backprobe sensor terminals with ignition ON (engine OFF) to verify reference voltage, ground continuity and signal voltage
- Perform wiggle test on harness while monitoring live data for intermittent changes
- Smoke-test EVAP system to confirm there are no external leaks affecting readings
- Measure resistance/continuity between sensor ground and vehicle chassis ground
Signal parameters
- Typical sensor signal: 0.5–4.5 V (varies by manufacturer) corresponding to tank vacuum/pressure range — confirm Alfa Romeo factory spec
- Reference supply: stable +5 V (or specified reference) on sensor reference terminal with ignition ON
- Sensor ground: near 0 Ω to chassis ground (
- Idling/KOEO expected signal: consult model-specific chart — abnormal fixed voltage (0 V or 5 V) indicates open/short
Diagnostic algorithm
- Connect a capable scan tool, confirm B1219 and any related EVAP codes (P0452/P0453/P0455 etc.). Note freeze frame and live data.
- Visually inspect sensor and harness at tank for damage, corrosion, loose mounting or water ingress. Repair obvious issues.
- With ignition ON (engine OFF) backprobe: verify sensor reference voltage (~5 V), signal voltage, and ground. Record values.
- If reference or ground missing, trace wiring to fuse/ECU and repair open/corroded connection. Check fuses and module power supply.
- If voltages present but signal out of range (stuck high/low or erratic), perform wiggle test while monitoring live data to detect intermittent wiring faults.
- Smoke-test EVAP system to rule out leaks that could cause out-of-range pressure readings and inspect sensor port for blockage.
- If wiring and EVAP plumbing check good but signal remains out of spec, replace fuel tank pressure sensor with OEM or specified part.
- After repair, clear codes, perform function test and drive/evap readiness cycle; re-scan to ensure code does not return.
- If code returns and wiring/sensor verified, consider module input circuit fault and pursue module-level diagnostics or replacement per manufacturer guidance.
Likely causes
- Damaged harness between sensor and module
- Water corrosion at sensor connector
- Failed sensor electronics
- Blown fuse or loss of 5 V reference supply
- Blocked or disconnected EVAP hose causing out‑of‑range readings
Fault status
Status
Fuel tank/EVAP pressure sensor circuit fault detected — signal out of range, open, shorted or intermittent. Check wiring, connector, sensor and EVAP plumbing.
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