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P0512 OBD-II Trouble Code: Starter Request Circuit

Check Engine Light

Diagnostic Trouble Code (DTC): P0512

P0512 code definition

The P0512 trouble code means that there has been a malfunction with the starter request.

What the P0512 code means

Starting a car is easy enough: put the key into the ignition and turn. However, the actual process behind this task is far more complicated. Mechanical keys are paired with resistors and radio transponders with unique codes. This last part is true with today’s push-button ignition systems. P0512 codes are only ever triggered in this type of vehicle.

The engine immobilizer system in a vehicle must be programmed to detect the transponder. Essentially, the transponder gives off a signal that the immobilizer can recognize with the help of a tiny antenna. Once it does this, the driver only needs to step on the brake pedal and press the start button to bring their vehicle to life.

If it isn’t able to detect this signal, yet an attempt is made to start the automobile, the immobilizer may lock out the starter and trigger the P0512 code.

What causes the P0512 code?

There are a few things that could cause this code:

  • There is a poor electrical connection hampering the immobilizer ability to detect the correct signal
  • The immobilizer antenna is damaged or broken
  • An open or short circuit is preventing the immobilizer from recognizing the correct signal
  • Something is wrong with the transponder inside the owner’s fob
  • There is insufficient voltage because of a weak battery (starting the engine demands the most amount of energy)

What are the symptoms of the P0512 code?

The most obvious symptom of the P0512 code is that the vehicle won’t start. However, there are times when the vehicle will actually cooperate but the code is still stored. Sometimes the automobile will start, but after a short delay. The driver may hear extended cranking before the vehicle finally complies. The Check Engine Light will mostly come on too.

How does a mechanic diagnose the P0512 code?

To begin the process of diagnosing this problem, the mechanic will start by using an OBD-II scanner to confirm the P0512 code has been stored and see if any others have been as well, (i.e. P0513 and P0633, both of which deal with the immobilizer).

After that, the mechanic will move on to inspect the fob for a bad antenna ring or damage that may be keeping it from working. If those components seem fine, they’ll examine all the wiring and electrical connectors connected to the immobilizer to ensure they are all working correctly.

Common mistakes when diagnosing the P0512 code

When the vehicle simply isn’t responding to the owner’s fob, most mechanics will correctly look at this issue early on. Unfortunately, if there is an audible cranking, many may assume that the problem has to do with the fuel and ignition system. Therefore, they will begin looking at the ignition coils, fuel injectors and fuel pumps for signs of a problem.

How serious is the P0512 code?

P0512 isn’t a trouble code that represents danger, but it will need to be repaired before an owner can begin using their vehicle again. Even if there is just a delay before the automobile starts, this will most likely change in the near future.

What repairs can fix the P0512 code?

The most common approaches to fixing the P0512 code are:

  • Repairing or replacing disconnected, damaged, corroded or shorted connectors, wiring and components
  • Replacing or repairing the immobilizer antenna
  • Repairing or replacing the fob
  • Addressing a lack of sufficient voltage

Additional comments for consideration regarding the P0512 code

Even if the owner is able to get their vehicle to start, if it’s clearly struggling and/or making an audible cranking noise, it’s a good idea to have the vehicle repaired right away. Though it may technically still be working, those sounds represent far bigger concerns on the horizon.

Need help with a P0512 code?

YourMechanic offers certified mobile 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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