P2509Charging System

ECM/PCM Power Input Signal Intermittent

The control module has detected an intermittent power input signal. The module power feed is cutting in and out, usually due to a loose connection, a marginal relay, or damaged wiring.

🚗 Yes, in many cases, but have it checked soon. Intermittent power loss can cause sudden stalling.

MEDIUM

severity

🎯 Top Causes, Ranked by Likelihood

#1Loose or corroded connection$40-$200

35%

An intermittent connection interrupts module power.

#2Marginal main relay$40-$150

25%

A relay that drops out intermittently cuts power.

#3Chafed or broken wiring$80-$300

25%

Damaged wiring makes and breaks contact with movement.

#4Poor ground$40-$200

15%

An intermittent ground disrupts the module supply.

🩺 Common Symptoms

Check engine light is on
Sudden intermittent stalling
Hard starting
Momentary electrical dropouts

💰 Repair Cost: DIY vs Shop

DIY Cost

$40-$300

Shop Cost

$120-$500

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose P2509

1Wiggle-test the module power and ground wiring while monitoring voltage.

2Inspect and reseat connectors and clean grounds.

3Test the main relay for intermittent dropout.

4Repair the loose or damaged connection, then clear and retest.

❓ Frequently Asked Questions

Why does my car stall randomly?

An intermittent power feed to the module can cut out briefly and cause a sudden stall.

Is this hard to find?

Intermittent faults can be. A wiggle test on the power and ground circuits often locates them.

Can I drive with it?

With caution, since it may stall unexpectedly. Have it repaired soon.

🔗 Related Codes

P2505P2506P2507P2510P0685