Hummer H3 P1682: Ignition 1 Switch → Circuit 2

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P1682 is a diagnostic trouble code that indicates that your Hummer H3’s ignition switch is having a voltage problem.  It is typically caused by a faulty ignition switch, although there can be other causes as well.

There are two “circuits” to the ignition switch.  The first one goes to the ECM through the throttle actuator control.  The second ignition voltage circuit (the one in question) goes through the ignition switch.

P1682 Hummer H3

 

P1682 Symptoms:  Hummer H3

With P1682 you’ll experience a no start or intermittent start condition.  The check engine light will be on as well.

Hummer H3 P1682

 

P1682 Causes:  Hummer H3

Here are the most common causes of P1682:

 

Ignition Switch

A bad ignition switch is the most common reason that P1682 will occur.  You’re going to need to test it before you replace it.  It’s a pretty straightforward process.  Here’s an article that covers everything that you would need to know about testing it.  

See also:  Hummer H3: Bad Ignition Switch Symptoms

 

Fuse Block

As the fuse block expands and contracts, it can eventually cause a hairline crack in the wire that runs from the ignition.  A good sign that this is the problem is when your H3 won’t start when the engine is hot, but it will once it cools all the way off.  Here is a fantastic video that covers this scenario.

This is particularly common on the Chevy Trailblazer, GMC Envoy, and Chevy SSR.  They all use a fuse block that is known to do this.

 

ECM

The ECM should be last on the list.  It is possible a bad ECM could be the cause.  At this point, it would be wise to take your Hummer H3 to a mechanic that is skilled in diagnosing a bad ECM before throwing money away on the problem. 

 

P1682 Affected Makes

This article is meant to help with diagnosing P1682 in vehicles manufactured by General Motors such as:

  • Buick
  • Cadillac
  • Chevrolet
  • GMC
  • Hummer
  • Isuzu
  • Oldsmobile
  • Pontiac
  • Saturn

It has a different meaning for other auto manufacturers, so make sure you are using the right article for your vehicle.

 

Conclusion: P1682 Hummer H3

Good luck diagnosing P1682 in your H3 made vehicle.  If there is anything that you would like to add, please leave a comment below.  Thank you!