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  • DTC P1682 stands for “Ignition 1 Switch Circuit 2,” and this is logged when the PCM detects a voltage difference between multiple ignition feeds.
  • Code P1682 is often caused by a malfunctioning ignition switch, a bad electrical connection, and an open or shorted ignition switch harness.
  • The most common symptoms of code P1682 include a lit check engine light, a weak or dead battery, or an engine that struggles to start.

Like any other component in your vehicle, the parts of your ignition may malfunction for several reasons. Code P1682 is a generic trouble code related to a fault in the ignition switch circuit.

What Does the P1682 Code Mean?

Diagnostic trouble code (DTC) P1682 stands for “Ignition 1 Switch Circuit 2.”

The ignition switch indirectly activates the relay that provides voltage from the battery to the ignition coil and the injectors.

multiple ignition feeds to the pcm ecm
There are multiple ignition feeds to the PCM/ECM and the PCM expects all of the voltages at those inputs to be very near the same voltage. If any of the five voltage feeds in the system shown in this diagram is less than the PCM/ECM expects to see, code P1682 or another similar code will be stored. Other systems are similar. | Image Source: Richard McCuistian.

A vehicle’s electronic control module (ECM) usually relies on two or more ignition 1 voltage circuits and will also have an always-hot battery circuit for “keep alive” memory. These circuits deliver power to all internal ECM circuits that are connected to the operation of your ride’s throttle actuator control (TAC). This switch is connected to the powertrain relay. Another circuit is used to apply power to other internal ECM circuits. It’s connected to the crank/run relay.

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Once the electronic control module (ECM) detects that there’s a voltage difference between these two circuits. It’ll trigger the P1682 code.

Note: The definition of code P1682 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

P1682 on GM Vehicles 

On GM vehicles, the code P1682 is defined as “Driver 5 Line 2.” The code is set when the vehicle’s computer detects that the voltage difference between circuit 1 and circuit 2 is higher than the maximum threshold set by GM.

What Are the Common Causes of the P1682 Code?

What Are the Common Symptoms of the P1682 Code?

How to Diagnose the P1682 Code

The P1682 is a manufacturer-specific code, so there’s no universal diagnostic procedure that would work for all vehicles. Keep in mind that the way a vehicle is designed tends to vary based on its manufacturer.

See also  Underhood Checks

If you’re not sure how to determine what’s causing the problem, it’s best to take your vehicle to an auto repair shop for a proper diagnosis. Otherwise, you can do it yourself.

How to Fix the P1682 Code

Resolving a P1682 error code can be challenging, especially if you don’t have the knowledge and equipment to clear the code. If that’s the case, your best option is to let a licensed mechanic address the issue for you.

But if you’re confident that you can resolve the trouble code on your own, make sure you have the right repair guide before you get started. Find vehicle-specific guides from resources like Chilton or an ALLDATA subscription.

Where to Get a New Ignition Switch for Your Ride

A P1682 code can be caused by a bad ignition switch or an issue with its harness or electrical connections. It’s a good thing that finding a replacement ignition switch for your ride is easy when you shop online.

See also  Bad Starter Solenoid Symptoms

There’s no need to go to multiple physical stores just to hunt down the right ignition switch for your ride. is your one-stop destination for quality automotive parts. We carry a wide selection of ignition switches that are designed for various makes and models.

Our ignition switches are engineered to match or exceed standards, so you can be sure that they’re reliable and durable. Use our vehicle selector to ensure the perfect fit, and place your order with just a few clicks.

Need to get back on the road as soon as possible? We’ll ship your order from the nearest distribution center, so you can expect your package to arrive in a matter of days.

Don’t let ignition problems ruin your vehicle’s performance. Explore our extensive catalog today, and order a new ignition switch for your ride. 

About The Authors
Written By Automotive and Tech Writers

The Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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