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Home / DTC / P1230 — Open Power to Fuel Pump Circuit

P1230 — Open Power to Fuel Pump Circuit

Detailed page for trouble code P1230.

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P1230

MERCURY P — Powertrain

Open Power to Fuel Pump Circuit

Brand: MERCURY
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Blown/incorrect fuse in fuel pump power circuit
  • Faulty fuel pump relay or relay socket
  • Open, chafed, corroded, or disconnected wiring between fuse/relay and fuel pump
  • Poor or missing ground at fuel pump
  • Faulty fuel pump or failed pump connector
  • Faulty fuel pump driver module or PCM output (manufacturer-specific)

Symptoms

  • Engine cranks but does not start (no fuel delivery)
  • No fuel pump prime or audible pump run when key is turned to ON
  • Intermittent stalling or no-start condition
  • No voltage measurable at fuel pump connector when pump should be powered
  • Possible diagnostic trouble codes related to fuel delivery

What to check

  • Verify customer complaint and reproduce no-prime/no-start condition
  • Inspect fuel pump fuse and fuse rating; replace if blown and retest
  • Check and swap fuel pump relay with known-good relay of same type
  • Visually inspect wiring and connectors for damage, corrosion, or disconnection
  • Backprobe fuel pump power and ground pins while key ON and during cranking
  • Measure voltage at relay output and at fuel pump connector (expect battery volts when commanded)

Signal parameters

  • Battery voltage at pump power pin during Key ON (prime) and cranking: ~11–14 V if circuit is good
  • Pump power circuit resistance: near 0 ohms between fused battery feed and pump power pin (short low-ohm path)
  • Fuel pump relay coil resistance: typical 50–200 ohms (vehicle-specific)
  • Fuel pump current draw when running: typically 4–10 A (varies by pump/model)
  • No voltage present at pump power pin when relay/fuse is open or circuit is broken

Diagnostic algorithm

  1. Confirm symptom: Turn key to ON; listen for pump prime for 2–3 seconds. If no sound, proceed.
  2. Check fuse: Locate and inspect fuel pump fuse(s). Replace a blown fuse and see if pump primes. If fuse blows again, suspect short to ground.
  3. Swap relay: Swap fuel pump relay with identical known-good relay (if available). If pump runs, replace relay.
  4. Backprobe at pump connector: With ignition ON and while cranking, backprobe power and ground wires at the pump connector. If no power but relay output has voltage, inspect wiring between relay and pump.
  5. Verify relay output: Backprobe relay socket while commanding pump (Key ON/crank). If relay coil is being energized but no output, check relay contacts and fused feed.
  6. Check fused battery feed: Verify continuity and voltage from battery/fuse box to relay and to pump. Repair any open circuits, corrosion, or poor connections.
  7. Check grounds: Measure resistance from pump ground to battery negative; repair if high resistance or open.
  8. Inspect wiring harness: Look for chafed wires, pinched sections, heat damage, or rodent damage along routing to fuel tank.
  9. Test pump: If power and ground are present but pump does not run, bench-test or apply fused 12 V to pump to verify operation; replace pump if it fails.
  10. Check control module/driver: If wiring and pump are good but PCM/fuel pump driver output is not switching, consult vehicle-specific service manual for PCM testing and replace only after confirming module fault.
  11. Clear DTCs and retest: After repairs, clear codes and verify normal pump operation and that code does not return.

Likely causes

  • Blown fuse or failed fuel pump relay
  • Disconnected or corroded connector at fuel pump
  • Open wiring between relay/fuse and pump due to chafe or broken conductor
  • Bad ground at the fuel tank/pump assembly
  • Failed fuel pump motor

Fault status

⚠️ Status
Open power circuit to fuel pump detected — no voltage reaching fuel pump when command is present. Possible open fuse, relay, wiring, connector, ground, or failed pump.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

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296

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