P0627
Fuel Pump A Control Circuit / Open
Powertrain Fuel and Air Metering Fuel pump control 🟡 Moderate — Fix within a week
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What This Actually Means
In plain language — no jargon

The ECU detected a break or disconnection in the electrical circuit controlling your fuel pump, similar to a light switch that won't turn on because the wire is cut. Without a working fuel pump, your engine won't receive gasoline and will either refuse to start or stall while running.

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Symptoms You May Notice
3 known symptoms for this code
Engine cranks but won't start or hard start condition
Vehicle stalls while driving or at idle
No fuel pump priming noise when ignition turned on
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors voltage and current flow through the fuel pump relay control circuit. It expects to see proper voltage drop across the pump motor when commanded on, and detects an open circuit when resistance is infinitely high or voltage doesn't reach the pump. A timeout or no-response condition triggers this fault.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Fuel pump circuit voltage 12-14V when pump commanded on 0V or insufficient voltage detected at pump
Fuel pump current draw 4-8 amps at operation 0 amps or open circuit detected
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Fuel pump relay
Locate the relay in the engine bay fuse box, swap it with an identical relay from another circuit to test if the fault clears.
2
Fuel pump wiring harness connector
Inspect the connector at the fuel pump or in-line for corrosion, loose pins, or damage; clean with dielectric grease and reseat firmly.
3
Fuel pump assembly
If wiring and relay check out, the pump motor itself has failed and the fuel pump unit must be replaced.