P0234
Fuel Pump Secondary Circuit Intermittent
Powertrain Fuel and Air Metering Fuel Pump Circuit 🟡 Moderate — Fix within a week
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What This Actually Means
In plain language — no jargon

Your car's backup fuel pump (usually in the tank) is losing electrical connection on and off, like a flickering light switch. The engine computer detects this intermittent signal dropout and logs the fault.

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Symptoms You May Notice
3 known symptoms for this code
Engine hesitation or stumbling during acceleration
Difficulty starting or occasional no-start conditions
Check Engine Light illumination
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECM monitors the secondary fuel pump relay circuit voltage and current draw during operation. It expects stable voltage supply and continuous current flow when the pump should be running. If the signal drops below threshold intermittently without the ignition being cycled, the fault is recorded.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Secondary Pump Voltage 12V steady during fuel demand Voltage drops below 10.5V intermittently or signal lost
Pump Current Draw 2-6 amps continuous Erratic current spikes or drops indicating connection loss
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Fuel pump electrical connector
Inspect and clean the secondary pump connector inside the fuel tank access panel for corrosion and poor contact.
2
Fuel pump relay
Swap the secondary fuel pump relay with an identical relay from another circuit to test if the fault follows.
3
Secondary fuel pump assembly
Replace the secondary pump and strainer if electrical checks pass but intermittent operation persists.