01 6-Speed DSG Automatic Transmission Common Faults: Causes, S… • 02 From Rack and Pinion to Steer-by-Wire: The Evolution of Ste… • 03 The Significance of Regular Car Servicing and Smart Fuel Co… • 04 Choking Up Your Ride? Signs You Need Throttle Body Cleaning • 05 Is it bad to brake while cruise control is enabled? • 06 Engine Cranks, Has Spark But Won't Start: Diagnose the Prob… • 07 Types of Spanners: Uses, Advantages, and Material Compositi… • 08 People Shocked After Mechanic Explains the Hidden Danger of… • 09 How to tell if a broken timing belt damaged the engine? • 10 Automatic Transmission Stuck in Gear? Here’s What You Need … •

DTC codes / Chrysler codes / P1284

P1284 · ChryslerFuel Injection Pump Battery Voltage Out Of Range

P1284 on Chrysler vehicles means the engine control module (ECM) has detected that the battery voltage feed to the fuel injection pump circuit is outside the expected range, either too low or too high. The ECM monitors this voltage to ensure the pump's electronic actuator receives stable power for precise fuel delivery, and it sets the code when the signal falls below or rises above calibrated thresholds.

SystemPowertrain
Code typeChrysler specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Engine may crank but fail to start or stall shortly after starting
  • Rough idle or misfire under load due to incorrect fuel delivery
  • Reduced engine power or limp mode in some driving conditions
  • Intermittent hesitation or stumble during acceleration

Common causes, most likely first

  1. Weak or failing battery that cannot maintain stable voltage under load
  2. Corroded, loose, or damaged battery terminals and cables
  3. Faulty fuel injection pump relay or blown fuse in the pump power circuit
  4. Chafed or open wiring between the battery, relay, and fuel injection pump
  5. Poor ground connection at the engine block or chassis
  6. Internal fault in the fuel injection pump actuator or its connector
  7. Voltage regulator issue in the alternator causing overvoltage

How to diagnose and fix it

  1. Perform a battery load test and inspect terminals for corrosion; clean and tighten as needed
  2. Check all fuses and relays related to the fuel injection pump circuit and replace any faulty ones
  3. Measure voltage at the fuel injection pump connector with the key on and engine cranking; compare to battery voltage
  4. Inspect the wiring harness from the battery to the pump for chafing, breaks, or loose connectors
  5. Test the ground circuit from the pump to the engine block using a voltage drop test
  6. If voltage supply is correct, test the fuel injection pump actuator resistance and compare to specifications
  7. Clear the code and verify repair with a test drive; if it returns, perform a wiggle test on the harness while monitoring live data

Voltage drop tests before parts replacement

  • A common misdiagnosis is replacing the fuel injection pump when the real problem is a weak battery or corroded ground that causes voltage to drop only under load.
  • The code can be set by a failing alternator that produces overvoltage, which damages the pump actuator over time, so always check charging system voltage.
  • Intermittent P1284 often traces to a chafed wire in the harness near the pump, which only shorts when the engine moves or the vehicle hits bumps.
  • Some Chrysler models require a relearn procedure after battery replacement or pump service, and skipping it can cause the code to reappear even with good voltage.

Can I keep driving with P1284?

If the engine runs normally, you can drive cautiously to a repair shop, but avoid heavy acceleration or towing. If the engine stalls, hesitates, or enters limp mode, stop driving and have the vehicle towed to prevent damage to the fuel injection pump.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Chrysler vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage