P1355 — Fuel Level Sensor B Intermittent/Bypass Line Monitor

How much does it cost to fix P1355?

Replace the fuel pump — $400–$900; Replace the pressure regulator or sensor — $150–$450; Clean or replace injectors — $200–$800; Replace the fuel filter — $80–$200. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Will P1355 clear itself?

Sometimes P1355 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What does OBD2 code P1355 mean?

Fuel Level Sensor B Intermittent/Bypass Line Monitor (P1355): a powertrain (engine/transmission) fault affecting the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Most often caused by contaminated or incorrect fuel, weak fuel pump or clogged fuel filter, faulty fuel pressure regulator.

What is the most common cause of P1355?

The most common causes are: contaminated or incorrect fuel, weak fuel pump or clogged fuel filter, faulty fuel pressure regulator.

What are the symptoms of P1355?

Drivers most often notice: hard starting or long cranking, fuel smell in severe cases, loss of power under load, increased fuel consumption.

When your engine control unit detects something wrong with how fuel reaches and mixes with air inside the cylinders, it logs a fault code. P1355 is one of those codes. Specifically, P1355 points to a problem detected in the fuel delivery system — the circuitry that monitors fuel level, pressure, and the bypass line that helps regulate mixture. The ECU stores this code when sensor readings swing outside acceptable limits for long enough that it cannot ignore the abnormality.

The engine control module watches this system constantly while the engine runs. Every few drive cycles, it evaluates whether the fuel pressure, injector behavior, and related sensors are behaving as the manufacturer designed them to behave. When those readings deviate from the expected window, the module counts the event. Once the threshold is crossed, P1355 gets stored in permanent memory, the Check Engine lamp illuminates, and a freeze frame snapshot is captured. That snapshot tells you exactly what rpm, engine load, coolant temperature, and vehicle speed existed at the moment the fault triggered — invaluable data when you start tracing the problem.

Symptoms of P1355 do not always announce themselves loudly at first. Some drivers notice the engine takes longer to start or cranks more than usual before catching. Others report a faint fuel odor, particularly when the fault is more advanced. Under heavier loads, the engine may feel sluggish or flat. Fuel economy typically worsens because the mixture ratio is off and the system compensates poorly. The Check Engine Light is the most reliable indicator, though rough idle and hesitation during acceleration also appear regularly. In severe cases, particularly if the fault goes unaddressed for many miles, the engine may stall unexpectedly.

Common Causes of P1355

Several root causes can trigger this code, ranging from simple mechanical issues to sensor failures:

• Air leaks in the intake tract or vacuum lines disturb the air-fuel mixture and confuse the monitor circuit
• Fuel injectors that are clogged, leaking, or electrically faulty deliver incorrect fuel quantities
• A faulty fuel pressure regulator allows rail pressure to drift above or below specification
• A damaged or loose fuel rail pressure sensor, or wiring problems at its connector, send false readings to the ECU
• Contaminated, diluted, or wrong fuel type disrupts normal combustion and sensor behavior

Symptoms You May Notice

• Hard starting or extended cranking time before the engine fires
• Noticeable fuel smell, especially under hood or near the tailpipe
• Reduced power when accelerating or climbing grades
• Fuel consumption climbing without a corresponding change in driving habits
• Check Engine Light remaining solid or flashing under load
• Rough idle, stumble, or hesitation during acceleration

How to Diagnose P1355

A systematic approach keeps you from replacing parts unnecessarily. Follow these steps in order:

1. Connect an OBD2 scanner — Confirm that P1355 is the active code and record the freeze frame data. This data reveals the driving conditions present when the fault occurred, guiding your inspection.
2. Scan for related codes — P0300-series misfire codes, fuel trim codes, or sensor-related codes often accompany P1355 and point toward the actual failing component. Also check manufacturer TSB databases for known issues on your specific make and model year.
3. Inspect wiring and connectors — Visually examine the harness serving the fuel rail pressure sensor, injector circuits, and related grounds. Look for broken insulation, corrosion, loose terminals, or chafing that could cause intermittent signal loss.
4. Measure fuel pressure — Using a quality fuel pressure gauge, check rail pressure at idle and again under manifold vacuum. Compare the readings to factory specification; low pressure suggests a pump or regulator problem, while erratic pressure points toward a regulator or injector leak.
5. Review fuel trim data — Access live data on short-term and long-term fuel trims. Sustained positive or negative trims indicate whether the ECU is adding or removing fuel to compensate, which narrows whether the problem is a leak, restriction, or sensor error.
6. Clear and retest — After repairs, clear the code and drive the vehicle through a complete drive cycle that reproduces the conditions in the freeze frame. If P1355 does not return, the repair was successful.

Repair Options and Costs

Not every P1355 repair requires expensive components. Work through the list from simplest to most costly before committing to a major replacement:

• Fuel filter replacement — $80–$200. A clogged filter starves the injectors and skews pressure readings.
• Fuel pressure regulator or sensor replacement — $150–$450. This corrects rail pressure that sits outside the acceptable band.
• Injector cleaning or replacement — $200–$800. Severely contaminated or electrically failed injectors may need ultrasonic cleaning or outright replacement.
• Fuel pump replacement — $400–$900. When the pump can no longer maintain adequate flow, it must be replaced.

The total bill for resolving P1355 typically lands between $80 and $900 depending on which part fails. Accurate diagnosis before purchasing parts is the single best way to keep costs reasonable — the pump scenario, though the priciest, is rarely the first thing to check.

Can You Drive with P1355?

Exercise caution if P1355 is stored. Fuel and mixture faults can produce hesitation at low speeds, unexpected stalling in traffic, and — in prolonged severe cases — damage to the catalytic converter from an overly rich mixture. Do not plan extended highway trips until the issue has been identified and addressed. Have the code diagnosed promptly to avoid being stranded or causing collateral damage to exhaust components.

Related OBD2 Codes

• P1300: Multi-faults - Bank 1 - With Low Side Shorts
• P1301: Multi-faults - Bank 2 - With Low Side Shorts
• P1302: Injector High Sides Shorted Together
• P1303: IDM Failure
• P1304: Cylinder Head Overtemperature Protection Active
• P1305: Boost Calibration Fault