P2509 OBD-II Trouble Code: ECM/PCM Power Input Signal Intermittent

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2509 code

P2509 is a diagnostic trouble code (DTC) for "ECM/PCM Power Input Signal Intermittent". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $114.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford $114.99 $20.0
Toyota $114.99 $20.0
BMW $124.99 $20.0
SCHEDULE P2509 DIAGNOSTIC Get a fair and transparent estimate upfront

P2509 code definition

The P2509 diagnostic trouble code is an indication that the ECM/PCM power input signal is having an intermittent problem.

Related Trouble Codes:

What the P2509 code means

The powertrain control module (PCM/ECM) receives information from several circuits. A contact relay is used to supply voltage to the PCM. The battery voltage circuit, ground circuit, and ignition power circuit are located on the contact relay. In addition to these three circuits on the contact relay, the PCM receives information through an output signal. If the voltage of these signals does not remain within the specifications that have been predetermined by the manufacturer, the PCM will store the P2509 diagnostic trouble code and the Check Engine Light will come on.

What causes the P2509 code?

  • Blown fuse
  • Faulty fusible link
  • Faulty circuits
  • Faulty battery
  • Faulty battery cables
  • Faulty PCM relay
  • Faulty powertrain control module

What are the symptoms of the P2509 code?

  • Check Engine Light on
  • Engine won’t start
  • Engine won’t crank
  • Engine shuts down
  • Check Engine Light faulty

How does a mechanic diagnose the P2509 code?

  • Diagnostic trouble codes should be diagnosed in the order that they appear in the PCM.

  • Use an OBD-II scanner to collect all trouble codes that have been stored by the PCM as well as freeze frame data.

  • Inspect the PCM wiring for damage, frays, breaks, and shorts.

  • If the PCM wiring has damage, frays, breaks, or shorts, repair or replace them.

  • Inspect the battery cables for loose connections, broken terminals, and corrosion.

  • Repair or replace battery cables as necessary.

  • Clear all diagnostic trouble codes from the PCM and operate the vehicle or complete a test drive to see if the P2509 diagnostic trouble code comes back.

  • If the P2509 diagnostic trouble code does come back, test the PCM relay to see if it is working properly.

  • Inspect and test the fuse and fusible link.

  • Clear all diagnostic trouble codes from the PCM and operate the vehicle or complete a test drive to see if the P2509 diagnostic trouble code comes back.

  • If the P2509 diagnostic trouble code does come back, test the electrical circuitry of the relay and fuse system.

  • Clear all diagnostic trouble codes from the PCM and operate the vehicle or complete a test drive to see if the P2509 diagnostic trouble code comes back.

  • If the P2509 diagnostic trouble code does come back, inspect the battery and charging system for proper operation.

  • Repair or replace the battery and/or charging system components as necessary.

  • Clear all diagnostic trouble codes from the PCM and operate the vehicle or complete a test drive to see if the P2509 diagnostic trouble code comes back.

  • If the P2509 diagnostic trouble code does come back, place the key in the ignition and turn it to the on position. If the Check Engine Light does not come on, a faulty relay is possible.

  • If the relay is not faulty, replacing and reprogramming the PCM may be necessary.

Common mistakes when diagnosing the P2509 code

It is common for misdiagnosis to occur when components other than the PCM are overlooked. Often the PCM does not need to be replaced and reprogrammed and repairing or replacing relay fuses, other fuses, battery wiring, or the battery itself can resolve the P2509 diagnostic trouble code. Replacing and repairing these components is much more cost effective than replacing and reprogramming the PCM.

How serious is the P2509 code?

A diagnostic trouble code is normally considered serious when it causes drivability issues or a change in performance. When the P2509 diagnostic trouble code is stored in the PCM the car will experience drivability and performance issues in that it may not start or the engine will completely shut down. For this reason, this diagnostic trouble code is considered serious and should be diagnosed and repaired as soon as possible.

What repairs can fix the P2509 code?

Additional comments for consideration regarding the P2509 code

The P2509 diagnostic trouble code is not always an indication that the powertrain control module (ECM/PCM) needs to be replaced and reprogrammed. It is common for low battery voltage or a bad relay fuse to be the cause of this trouble code. This should not be overlooked during diagnosis of the P2509 trouble code.

Need help with a P2509 code?

YourMechanic offers certified mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

Check Engine Light
trouble codes
P2509

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P2509 code.

SCHEDULE P2509 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(7400)

Rating Summary
6879
249
58
41
173
6879
249
58
41
173
 at YourMechanic

David

13 years of experience
393 reviews
David
13 years of experience
Chevrolet Malibu L4-2.4L - Check Engine Light is on Inspection - Marietta, Georgia
He explained everything to me in detail on what I needed to know about my car. Definitely recommend him for getting the job done.
 at YourMechanic

Raymond

37 years of experience
402 reviews
Raymond
37 years of experience
Toyota Camry L4-2.2L - Check Engine Light is on - Las Vegas, Nevada
Raymond did a great job however I was charged for two hours labor and he was only here less than 45 minutes. should I expect this on future appointments with your mechanic ?
 at YourMechanic

Shane

17 years of experience
217 reviews
Shane
17 years of experience
Volkswagen EuroVan V6-2.8L - Check Engine Light is on Inspection - Austin, Texas
Arrived on time. Explained the issues he found and how he will fix it. I have parts on order and will schedule an appointment to have Shane install the parts when they arrive.
 at YourMechanic

Kanstantsin

19 years of experience
51 reviews
Kanstantsin
19 years of experience
Ford F-150 V8-4.6L - Check Engine Light is on Inspection - Littleton, Colorado
Kanstantsin arrived early. Was very courteous and professional. Will highly recommend to anyone. Thank you Kanstantsin.


More related articles

P2740 OBD-II Trouble Code: Transmission Fluid Temperature Sensor B Circuit
P2740 means system is receiving a high temperature reading due to low fluid level or a failing transmission or other electrical or sensor problem.
P2711 OBD-II Trouble Code: Unexpected Mechanical Gear Disengagement
P2711 means a malfunction was detected from the output shaft speed sensor due to failing transmission components or electrical issues and/or problems.
P0623 OBD-II Trouble Code: Generator Lamp Control Circuit
P0623 means there is a voltage problem between the ECU and the generator control module due to bad battery or alternator, or a weak or dead battery.

Related questions

Car died after battery, brake, and Check Engine light came on.
Hi there. When you get this combination of warning lights and symptoms it is typically the result of a battery that has failed. If the battery voltage gets low enough then the check engine light and the brake light can...
Need to know if I should replace my turbo or not
Hi, thanks for writing in. The turbo system is comprised of several different components. Without knowing the exact trouble code, it would be hard to guess at what is going on. There could be a bad sensor, a leaking intake...
Transmission slipping and Check Engine Light is on
Hi there. From your description of the transmission slipping when warm, leads me to believe, the transmission fluid is not low. The vehicle's computer is, apparently, recognizing the fault and turns the Check Engine Light on (https://www.yourmechanic.com/services/check-engine-light-is-on-inspection). Accessing the codes...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com