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2020 Dodge Ram 1500 - Cranks but No Start, P0627 Code

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Kevin B. · rep 0 · May 22, 5:38 AM · 1 replies · solved · Question

Vehicle: 2020 Dodge Ram 1500 Laramie

Hello everyone,

I'm having a major issue with my 2020 Dodge Ram 1500 (5.7L Hemi, Laramie trim) with about 45,000 miles. This morning, it just cranks and cranks but won't fire up. It was running perfectly fine yesterday.

I plugged in my scanner, and it's showing a P0627 code: 'Fuel Pump 'A' Control Circuit/Open'. This definitely points to a fuel delivery problem, but I'm not sure where to start troubleshooting.

Could it be the fuel pump itself, a relay, or maybe a fuse? I've checked the fuses in the under-hood box, and they all look good. Any advice on how to diagnose this further before I have to tow it to a dealer?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:38 AM

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ClearTheCode admin answer:

The P0627 code, 'Fuel Pump 'A' Control Circuit/Open,' is a clear indicator that your Ram's engine computer (PCM) is not detecting the proper operation or circuit integrity of the primary fuel pump. This is why your truck cranks but won't start – it's not getting fuel.

Here are the most common causes and diagnostic steps:

  1. Fuel Pump Relay: This is a very common failure point. The relay sends power to the fuel pump. If it's faulty, the pump won't receive power. Many vehicles have a similar relay for another system (like the horn or a fan) that you can swap in temporarily to test.
  2. Fuel Pump Fuse: While you mentioned checking fuses, double-check the specific fuse for the fuel pump. Consult your owner's manual for its exact location and rating. A blown fuse means an open circuit.
  3. Wiring Issue: There could be a break, short, or corrosion in the wiring harness leading to the fuel pump or its control module. This is especially true if the truck has been exposed to harsh conditions or recent work.
  4. Fuel Pump Control Module (FPCM): Modern vehicles often use a separate module to control the fuel pump, varying its speed and pressure. A faulty FPCM can prevent the pump from operating.
  5. Fuel Pump Itself: The fuel pump inside the tank could have failed. If it's not receiving power or is mechanically seized, it won't deliver fuel.

Diagnostic Steps:

  • Listen for the Pump: Turn the ignition to the 'ON' position (don't crank). You should hear a faint hum from the rear of the truck for a few seconds as the pump primes. If you hear nothing, it's a strong indicator of a power supply or pump issue.
  • Check Fuel Pump Relay: Locate the fuel pump relay in your fuse box (owner's manual). You can often swap it with an identical, non-critical relay (like the horn relay) to see if the problem resolves.
  • Check for Power at the Pump: This requires a multimeter and some automotive electrical knowledge. Safely lift the truck and locate the fuel pump connector on top of the fuel tank. With the ignition 'ON', check for 12V at the appropriate pins. If there's power but no hum, the pump is likely bad. If no power, trace back through the wiring, FPCM, and relay.

When to see a shop:

If you've checked the relay and fuse and still have no success, or if you're uncomfortable working with electrical systems and fuel lines, it's time to call for a tow to a professional mechanic. Diagnosing wiring issues or replacing the fuel pump (which often requires dropping the fuel tank) is best left to experienced technicians with the right tools and safety equipment.

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