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.


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.
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?
- Malfunctioning ignition switch
- Open or shorted ignition switch harness
- Electrical connection issues
- Faulty ECM
What Are the Common Symptoms of the P1682 Code?
- Illuminated check engine light
- No start condition
- Weak or dead battery
- Noise coming from the hood
- Dim headlights
- Stalling
- Issues with the fuse
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.
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.
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.