Error code · Engine

P1682 — Ignition 1 switch circuit 2

Don’t put off the repair

For makes: Chevrolet, Cadillac, GMC

A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.

Possible causes

What you can do yourself

  1. The engine may not start or may stall.
  2. Check the engine unit fuses and relays under the hood and see that they sit tight with no corrosion.
  3. Check the battery and terminals: at low voltage control units lose communication.
  4. Per GM bulletin PIT6486 (Envision 2024–2026) the cause was inside the engine harness fuse block — it was replaced.

Stop and don’t drive on if:

  • The Check Engine light is flashing
  • The temperature gauge is in the red or the overheating light is on
  • The red oil pressure light is on
  • Smoke from under the bonnet, a burning or petrol smell
  • Strong jerking, knocking from the engine, or the car barely moves
OOleg’s tip: check the connector

Often the cause is simple — there is no contact in the connector (plug). Look at the connector from the back: remove the rubber seal and you will see whether a wire is corroded or has come off completely. Corrosion shows up as green deposits. Ideally, gently pull each wire towards you one at a time: a sound wire stays in place, while a corroded one simply comes off — it needs to be repaired.

Unplug and inspect connectors with the ignition off.

This is the GM meaning (Chevrolet, Cadillac, GMC). On other makes this number means something else: if your car isn’t made by GM, change the make at the top.

Source: GM PIT6486 (static.nhtsa.gov)

The explanation comes from the error code reference in the AvtoElektrik PRO app.

Need a mechanic’s help?

Couldn’t fix it yourself? Oleg, an auto electrician, does computer diagnostics and repairs: he comes out anywhere in Almaty or sees you at his workshop.

Want to figure it out yourself?

Oleg’s course “Car computer diagnostics with a scan tool”: how to hook up a scanner, read codes and live data, and use them to find the cause. The first lessons are free.

Scan tool diagnostics course →

Nearby codes

All codes in P10xx–P16xx →

Who keeps this reference

The reference is kept by Oleg Dmitriev, an auto electrician from Almaty with 26 years of experience: computer diagnostics of cars and trucks, repair of control units (ECUs). Can’t find the cause? Message him.