P1339 — Fuel Pump Control Module Communication Failure

Does P1339 mean the fuel pump itself is defective?

Not necessarily. P1339 identifies a communication-circuit fault involving the fuel pump control module, and the pump or module may sometimes continue operating normally.

Can the vehicle safely be driven with P1339?

Only cautiously if the engine runs consistently and no fuel-system warning is present. Any stalling, no-start behavior, fuel odor, or visible leak should stop driving immediately.

Can an ELM327 or AIScanAuto reader diagnose P1339?

They can confirm whether P1339 is stored and may reveal related codes, but generic hardware may not communicate with the fuel pump control module or display live circuit data.

What should be checked before replacing the fuel pump control module?

Check the module connector, power supply, grounds, and communication wiring to the engine controller first. P1339 alone does not prove that the module or fuel pump has failed.

When your OBD2 scanner displays P1339, the engine control unit has identified that a sensor or actuator circuit is behaving outside its programmed acceptable range. This generic powertrain code flags any abnormality in the monitored system's electrical performance — the exact component depends on which circuit the control module was watching when the failure occurred. P1339 falls into the broader category of vehicle electrical faults and gets stored once the out-of-range condition persists long enough to meet the manufacturer's trigger threshold.

Modern ECUs run constant self-checks on every sensor and actuator circuit. They compare actual voltage, resistance, and signal patterns against factory specifications. When something drifts outside those boundaries for a set number of consecutive drive cycles, the module logs P1339 and illuminates the Check Engine light. The freeze frame data captured alongside the code is invaluable — it records engine speed, load, coolant temperature, and vehicle speed the instant the fault was detected, giving you precise conditions to replicate during diagnosis.

Symptoms of P1339

When P1339 sets, you may notice one or more of the following:

• Check Engine light is illuminated on the dashboard
• The vehicle may enter limp-home mode, limiting speed and RPM until the issue is resolved
• The system tied to the faulty circuit runs intermittently or stops functioning entirely
• Fuel economy may drop noticeably during normal driving
• In rare cases involving critical sensors, a no-start condition becomes possible

Common Causes of P1339

The most frequent reasons this code appears include:

• A weak or intermittent ground connection at the affected component or control module
• Corrosion, moisture intrusion, or physical damage to electrical connectors
• Broken or frayed wiring within the circuit harness from age, heat, or accidental damage
• An internal driver failure within the ECU or PCM itself
• Loose terminal connections allowing high resistance or complete opens
• Chafed wiring that intermittently shorts to ground or another circuit

Diagnosing P1339

Follow these steps to pinpoint the exact failure:

1. Connect your OBD2 scanner and verify P1339 is present. Record the freeze frame data — this snapshot shows engine RPM, load, temperature, and speed at the moment the fault occurred and helps you reproduce the failure condition.
2. Scan for any additional diagnostic trouble codes. Related codes often point directly to the failing component or circuit. Check manufacturer TSB databases and nhtsa.gov for service bulletins covering your specific make, model, and year — many P0xxx codes have documented factory fixes or software updates.
3. Perform a hands-on inspection of all wiring and connectors associated with the affected circuit. Look for broken insulation, bent pins, corrosion buildup, or any sign of water entry.
4. With the connector unplugged, check reference voltage, ground, and signal wire continuity using a multimeter. Compare your readings against manufacturer specifications.
5. Perform a wiggle test on the harness while monitoring live data on your scanner. Any signal dropout or erratic reading confirms an intermittent open or short within the wiring.
6. Clear the code and complete a test drive that mimics the freeze frame conditions — the same RPM, load, temperature, and speed range. If P1339 returns, you have confirmed an active fault rather than an intermittent event.

Repair Options and Costs

Address the cheapest possible causes before replacing expensive components:

• Wiring repair or connector replacement: $80–$250
• Sensor or actuator replacement: $150–$500
• Control module repair or replacement: $300–$1,000

Total Cost to Fix P1339

Your actual repair bill depends entirely on what component is failing. Based on typical independent shop labor rates in the United States, most P1339-related repairs fall between $80 and $1,000 total. Wiring and connector issues represent the majority of cases and cost the least. Sensor or actuator failures occupy the middle range, while control module work sits at the high end. An accurate diagnosis before purchasing parts is essential — the worst-case scenario is rarely the first thing to investigate.

Can You Drive with P1339?

In most situations, the vehicle remains drivable when P1339 is stored. You may experience reduced performance, disabled convenience features, or a loss of power depending on which system is affected. However, if the related fault causes stalling, prevents the engine from starting, or triggers warnings related to braking or steering systems, treat this as urgent and seek repairs immediately.

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