P1564 — Injection Pump Reduced-Fueling Request

Does P1564 prove the injection pump control module has failed?

No. P1564 records a reduced-fueling request from the injection pump control module, but the actual fault may be wiring, a pressure sensor, fuel delivery, or an internal module problem.

Can the vehicle be driven with P1564 stored?

A short trip may be possible if the engine runs normally, but reduced power, stalling, or a no-start condition can occur. Heavy loading should be avoided until the code is diagnosed.

What should be checked first when P1564 appears?

Start with stored freeze-frame data and live fuel-rail pressure, if available. Then inspect fuel supply conditions, sensor readings, module connectors, grounds, and the related harness.

Will clearing P1564 repair the underlying problem?

No. Clearing the code only resets the controller's memory. If the pressure, wiring, fuel-supply, or module fault remains, P1564 will usually return during subsequent operation.

When your engine control unit runs its self-check routine, it monitors dozens of sensors and actuators at all times. If any of these components sends readings outside the expected range or behaves in an unexpected way, the ECU logs a fault code. Code P1564 appears when self-diagnostics detect abnormal readings or behavior in a sensor or actuator circuit. The specific circuit involved varies by make and model, which is why you'll sometimes see this code followed by a description tied to the affected system.

The powertrain control module doesn't trigger P1564 on a single bad reading. Instead, it waits until the fault shows up repeatedly under the same operating conditions. This threshold prevents false alarms from temporary electrical noise or one-time glitches. When P1564 does get stored, the ECU also captures a freeze frame snapshot — engine load, RPM, coolant temperature, and vehicle speed at the moment the fault occurred. That snapshot is your best clue for recreating the problem during diagnosis.

Once the control module decides the fault is real, it turns on the Check Engine light to warn you. P1564 means something in an electrical circuit is not performing as it should, and tracking down that circuit is the first step toward fixing it.

Symptoms of P1564

• The system tied to this fault operates intermittently or quits working entirely
• Check Engine light remains illuminated
• Fuel economy drops noticeably in some vehicles
• The car may enter limp-home mode, limiting power and speed
• Reduced function of the auxiliary system controlled by the affected circuit
• In rare cases, rough idle or hesitation under load

Common Causes of P1564

• An open circuit, short circuit, or damaged wire somewhere in the harness
• A weak or corroded ground connection at the component or ECU
• Connector pins that are spread, corroded, or not fully seated
• A failed driver inside the powertrain control module itself
• A sensor or actuator that has stopped sending or receiving signals correctly
• Wiring insulation worn through from heat, chafing, or animal damage

How to Diagnose P1564

1. Plug in an OBD2 scanner, verify that P1564 is active, and record all freeze frame data before doing anything else — these parameters show exactly what conditions triggered the code.
2. Look for any related diagnostic trouble codes stored alongside P1564. Secondary codes often point directly to the failing component. Also check your manufacturer's technical service bulletins using your VIN; some P0xxx codes have documented fixes or calibration updates.
3. Perform a thorough visual inspection of the wiring and connectors associated with the --- circuit. Look for melted insulation, green corrosion on terminals, bent pins, or any sign the connector has been pulled loose.
4. With a multimeter, check reference voltage, ground integrity, and signal continuity at the component's connector. Compare your readings to specifications in a repair manual.
5. Gently flex the harness while watching live data on your scan tool or multimeter. If the signal cuts out or spikes, you have found an intermittent wire break.
6. Clear P1564, then drive the vehicle through the exact conditions captured in the freeze frame — same load, RPM range, temperature, and speed. If the code comes back, you have confirmed a real fault.

Repair Options and Costs

Depending on what your diagnosis reveals, here is what you can expect to pay for parts and labor at an independent shop in the United States:

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

Total Repair Cost for P1564

The final bill hinges entirely on which part is at fault. In most cases, the problem is a simple wiring issue or a single failed sensor — both of which fall on the lower end of the price range. Control module failure is the least common cause but the most expensive to address. Plan on spending anywhere from $80 to $1,000 total. Getting an accurate diagnosis before purchasing parts almost always saves money, because the most dramatic repair scenario is rarely the first one to investigate.

Can You Drive with P1564?

For most vehicles, P1564 is a non-critical fault. The car will typically continue running, though you may notice reduced performance from the affected system or a loss of an auxiliary function such as emissions controls. Serious symptoms like stalling, failure to start, or warnings related to brakes and steering are uncommon with this code. That said, ignoring an electrical fault can eventually cascade into bigger problems, so have it checked within a reasonable timeframe.

Driving safety verdict: Short. You can drive the vehicle, but get the code diagnosed and repaired promptly to avoid potential strand or safety concerns.

Related OBD2 Codes

• P1500: Secondary Switch Solenoid Circuit Malfunction
• P1501: APLSOL Solenoid Circuit Malfunction
• P1502: RCNT Solenoid Circuit Malfunction
• P1503: SPCUT Solenoid Circuit Malfunction
• P1504: TCSPL Solenoid Circuit Malfunction
• P1505: Vehicle Speed Sensor Intermittent