P1238 – Fuel Pump Secondary Circuit Malfunction: Symptoms, Causes, Diagnosis & Repair Cost (2026 Guide)

P1238

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Overview

The control module stored P1238 because it detected a problem with: Fuel Pump Secondary Circuit Malfunction.

P1238 relates to Fuel Pump Secondary Circuit Malfunction. Use a quality scan tool, follow wiring diagrams for your vehicle, and confirm tests before replacing expensive parts.

What does the P1238 code mean?

When P1238 is set, the vehicle’s diagnostics detected an issue described as: Fuel Pump Secondary Circuit Malfunction. In practice, the ECM/PCM (and related modules) compare sensor inputs, commanded outputs, and self-tests for that subsystem. The exact repair depends on whether the fault is wiring-related, component-related, or a rationality/performance issue for this circuit or system.

Common symptoms of P1238

  • Hard starting
  • Rough idle
  • Hesitation or stumble
  • Check engine light
  • Fuel odor in some cases
  • Reduced fuel economy

Possible causes

  • Fault affecting Fuel Pump Secondary Circuit Malfunction (wiring, connector, or component)
  • Control module strategy or calibration issue
  • Electrical fault in the monitored circuit
  • Component failure in the described system
  • Control module or software calibration issue (less common—verify tests first)
  • Past repairs or aftermarket parts causing out-of-spec operation

How to diagnose P1238

  1. Scan for P1238 and review freeze frame / pending codes for related faults
  2. Inspect connectors and wiring related to: Fuel Pump Secondary Circuit Malfunction
  3. Compare live data and commanded vs actual values for the affected system (per service information)
  4. Perform circuit tests appropriate to the fault type (continuity, voltage, resistance) before replacing parts
  5. Confirm power and ground integrity at the relevant module or sensor
  6. After repair, clear DTCs and verify under the conditions that originally set P1238

Tip: Use a scan tool that shows live data and freeze frame for the conditions when the code set.

Severity of code P1238

Moderate: Have this code diagnosed soon; ignoring it can lead to worse fuel economy, repeat failures, or secondary damage.

Can you drive with P1238?

Short trips may be okay if the vehicle feels normal, but have it diagnosed—especially if performance, safety warnings, or overheating are present.

Avoid heavy acceleration, towing, or long highway drives until the cause of P1238 is confirmed and repaired.

How to fix it (step-by-step)

  1. Start with visual inspection and connector cleaning/tightening where needed
  2. Confirm failure mode with testing—avoid swapping parts without evidence
  3. Repair wiring or replace the failed component per manufacturer procedure
  4. Clear faults, run relearns if required, and road test to confirm

Repair & fix options

  • Test component against service limits
  • Clear codes and verify with drive cycle
  • Inspect connectors and wiring first
  • Clear codes and verify repair with a drive cycle and readiness where applicable
  • Reinspect related monitors if the code returns after repair

Typical repair cost

$120 – $3,500+ depending on cause

Estimated cost breakdown for P1238
Repair type Typical range
Diagnostic And Minor $120 – $400
Common Component Work $180 – $900
Major Subsystem Repair $400 – $2,200
Severe Or Replacement $900 – $3,500+

How to help prevent P1238 in the future

  • Fix new codes early before secondary damage or catalyst stress
  • Keep connectors clean and secure; address rodent or water intrusion in harnesses
  • Use the correct fluids/parts for your vehicle and service intervals
  • Avoid ignoring pending codes after battery work or repairs

When to see a mechanic

Schedule diagnosis if the check engine light is on, drivability is worse, or you notice new noises, smells, or warning lamps. For safety-related (SRS/ABS) or overheating symptoms, prioritize a qualified shop immediately.

Common mistakes when diagnosing P1238

  • Replacing sensors/modules without verifying wiring and reference voltages
  • Ignoring related codes that identify the real root cause
  • Clearing codes without a verification drive cycle

Common vehicles & notes for P1238

  • Ford / Chevrolet models (common examples—verify for your vehicle)
  • Toyota / Honda applications vary by engine and model year
  • Many other makes—this is a standardized OBD-II definition: Fuel Pump Secondary Circuit Malfunction

P1238 is reported across many platforms including Ford, Chevrolet, Toyota, Honda. Always use VIN-specific service information for testing limits and calibration steps.

Frequently asked questions

What does P1238 mean?

P1238 indicates a fault involving Fuel Pump Secondary Circuit Malfunction, based on what the control module detected during self-tests or live monitoring.

Is it safe to drive with P1238?

If the vehicle runs normally and no warning lights are flashing, short trips may be reasonable—but avoid ignoring symptoms like misfire, overheating, ABS/SRS warnings, or major loss of power.

How much does it cost to fix P1238?

Typical repairs often fall in the ranges shown on this page, but final cost depends on labor rate, parts quality, and whether the issue is wiring vs. a major component.

What is the most common cause of P1238?

Most shops start with wiring/connectors and the directly monitored component for “Fuel Pump Secondary Circuit Malfunction,” then expand testing if the fault returns.

Will P1238 clear itself?

It may become intermittent, but if the underlying fault remains, the code will usually return—especially after a drive cycle.

Can a weak battery cause P1238?

Low system voltage can cause odd sensor/module behavior, but you should still validate the actual DTC and perform normal circuit/component tests.

Related tools

This information is for educational purposes only and is not a substitute for hands-on diagnosis. Always follow manufacturer service information and consult a qualified automotive technician for repairs.