AutoCodesGMC – P1682 GMC

P1682 GMC Code - Ignition 1 Switch Circuit 2

Quick Answer

There are 2 ignition 1 voltage circuits supplied to the Engine Control Module (ECM). Common causes include Faulty ignition switch, Ignition Switch harness is open or shorted, Ignition Switch circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1682 GMC indicates Ignition 1 Switch Circuit 2.
Common causes
Common causes include Faulty ignition switch, Ignition Switch harness is open or shorted, Ignition Switch circuit poor electrical connection.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 119,456
How popular is this code, among other codes? Medium
Table of contents Created and updated by William Orellana on Aug 11, 2022
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Code P1682 GMC Description

There are 2 ignition 1 voltage circuits supplied to the Engine Control Module (ECM). The first ignition circuit is provided by the powertrain relay, through a fuse. This ignition 1 voltage circuit supplies power to all the internal ECM circuits associated with the throttle actuator control (TAC) operation. The second ignition 1 voltage circuit is supplied by the run/crank relay through a fuse and is used to power the remaining internal ECM circuits. If the ECM detects a voltage difference between the 2 ignition 1 voltage circuits, DTC P1682 will set.
OBDII Code P1682 GMC - Ignition 1 Switch Circuit 2 - AutoCodes.com
P1682 GMC Code - Ignition 1 Switch Circuit 2

What are the Possible Causes of the DTC P1682 GMC?

  • Faulty ignition switch
  • Ignition Switch harness is open or shorted
  • Ignition Switch circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How to Fix the DTC P1682 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1682 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P1682 GMC code?

Need more information on how to fix the P1682 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific GMC Models

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1682 GMC Code

1. What are the common symptoms of OBDII code P1682 GMC (Ignition 1 Switch Circuit 2)?

Symptoms may include issues with starting the vehicle, intermittent stalling, or warning lights on the dashboard.

2. What are the possible causes of OBDII code P1682 GMC?

Potential causes include a faulty ignition switch, wiring issues, a malfunctioning ignition lock cylinder, or a problem with the vehicle's computer system.

3. How can I diagnose the source of OBDII code P1682 GMC?

Diagnosis typically involves checking the ignition switch for proper operation, inspecting the wiring for damage or loose connections, and using a diagnostic scanner to read the trouble codes.

4. Can a DIY enthusiast repair OBDII code P1682 GMC?

While some basic troubleshooting like checking connections and fuses can be done by DIYers, diagnosing and repairing complex issues related to this code may require professional assistance.

5. What are the implications of ignoring OBDII code P1682 GMC?

Ignoring this code can lead to more severe issues over time, such as the vehicle not starting at all or unexpected stalling while driving.

6. Is it safe to drive with OBDII code P1682 GMC active?

It is not recommended to drive with this code active, as it may pose a risk of sudden stalling, which can compromise safety on the road.

7. How much does it typically cost to repair OBDII code P1682 GMC?

The cost of repairs can vary depending on the exact cause of the issue, but it may range from a few hundred to a few thousand dollars, including parts and labor.

8. Can resetting the OBDII code P1682 GMC turn off the check engine light?

Resetting the code may temporarily turn off the check engine light, but if the underlying issue is not addressed, the light is likely to come back on after a short period.

9. Are there any preventive measures to avoid OBDII code P1682 GMC in the future?

Regular maintenance, such as checking the condition of the ignition system components and addressing any issues promptly, can help prevent the recurrence of this trouble code.

10. Will OBDII code P1682 GMC affect the vehicle's fuel efficiency?

In some cases, this code may lead to poor fuel efficiency due to irregular engine operation, so addressing the underlying issue promptly can help maintain optimal fuel economy.

Discuss the causes and fixes for P1682 GMC OBDII Code

  • My mother-in-law's 2008 Chevrolet Impala has a terrible start issue. Whenever it is cold there doesn't seem to be a connection to the starter. It takes several minutes turning on and off the ignition into the start position before it will finally crank. The starter, starter relay, battery and ignition switch have all been replaced. The car has been to the dealer five times and they can't figure out what's wrong with it. It finally now shows a p1682 code which it hasn't earlier. I noted that whenever the car won't start it won't start using the remote start on the key fob also. I also noted that after the car warms up and will then start every time, the key fob remote start still doesn't work at that time. The last time it was at the dealership they said they thought it was fixed but they didn't know what if anything they had done to fix it. They didn't charge for that trip. It worked for several weeks after that, but not is back in the no-cold-start mode again. The only thing that hasn't been replaced is the computer.

  • Although I couldn't find any similar cases on a national database of repairs for the 2008 Impala, it does look like the Powertrain Control Module (PCM) may have and internal problem.

  • I have a 2008 GMC Acadia and it started shifting funny, like a delayed shift and a little harder than usual. Got the codes read and its throwing 3. P0700, P1682 and P0716. Any suggestions on where I can start first as I have just spent $2k on the front end just two weeks ago?

  • The P1682 it is not related on how the transmission shifts. The P0700 is an information code and just means that there is a problem with the transmission. You should focus more on the P0716 code.

    The most common problem for the P0716 code is the Transmission Input Shaft Speed Sensor and/or the transmission filter.

    I recommend start by changing the transmission fluid and filter.

    P0716 GMC - Transmission Input/Turbine Speed Sensor Range/Performance
    Read more: https://www.autocodes.com/p...

  • Hello I have a 2007 Envoy Denali which has codes P1682, PO689 and Po690. I have paid this mechanic who has told me that it was my modular system and that I needed to change my ignition switch which I paid to have them both repaired. My car drove me the next day to work but to only stop after picking up my daughter again for the 2nd time. Now he say its my Crank Position Censor. How do I know that to be true after all of this? Any suggestions on what I should do at this point?

  • For the P1682, P0689 and P0690 codes the ignition switch was the most likely cause of the codes. The Crankshaft Position Sensor is no related to the previous codes, but it's possible that now you may have the code for the Crankshaft Position Sensor code. Do you know what code do you have now?

  • my gmc acadia p1682 comes up. when i turn it off the check ingine light stays on and my battery get eaten up within a half hour. ive changed my ignition module still having this problem. it also comes and goes as it wants sometimes thr truck is fine and then its like this. any suggestions

  • Sounds like you have a problem with the ignition switch. What year is your Acadia?

  • A week ago my 2009 impala had the same code p1682 after it completely shut off while driving showing “engine power reduced” with the engine light on and I changed the fuse block with one from the junkyard and it started working fine and a week later same thing happens it shuts off while driving and same code please help

  • Other than the ignition switch, I have not seen any other components setting the P1682 code. The ignition switch is the most common problem. Also, make sure you check the battery and alternator.

  • engine ran fine before I switched transmission and now i have
    P2101 -Throttle actuator position
    P1682 -Ignition switch circuit 2
    P2176 -Minimum throttle position not learned

  • Did you use a transmission from the same vehicle model, year and engine? if you did, then you need to double check the installation, you may accidentally disconnected or damage a connector.

  • I have a 2008 gmc acadia went out to vehicle and the radio was running, got into driver seat put key in ignition and it turned off, but check engine light is on, code is p1682, started vehicle then turned off and engine was still running, what could this be, please help

  • There are some tests that needs to be done in order to determine exactly what the problem is, but it's possible that you may have a problem with the ignition switch or the ignition switch relay.

  • Thank you I will try this

  • Currently working on a 2016 GMC 2500 with a 4.8l vehicle has P1682 code. the vehicle had no issues starting and running but we replaced the module. Now the vehicle will not start with the new or old module. any suggestions would be greatly appreciated.

  • Having the same problem on my 2014 GMC Acadia. I've replaced the ignition switch, the battery and the MAF sensor. What happens is my cars traction control turns off, reduce engine flashes and goes into limp mode. Most of the times I can turn it off and back on. Some times it takes a few. It has refused to crank resulting in a row to the dealer. They said it was a faulty wire behind the fuse box. Nope, didn't fix it.

  • Recently got the P1682 on our car after it intermittently wouldn't start after being run for 30+ mins. Drove it to my brother n laws shop, (45miles away) had it scanned and no codes. They started it and turned it off about 15 to 20 times and couldn't get it to do what it had been doing (cranking but not starting). So drove Towards home, (45 miles) stopped and put gas in of which we shut car off for. Then proceeded to my aunts, about 2 miles from our house. Shut the car off. about an hour later it wouldn't start again, and was now showing the dummy light. After we waited about 2 hours for it to start again we drove home. I waited a while and then took it to auto zone to have it scanned since it was throwing a code, and it threw P1682 and P0443. Purge valve was just replaced less than a week ago. Please help been dealing with this for a couple of weeks where it will crank and not start. autozone says their system says to replace ecm.

    Its a 2005 Gmc Envoy Denali 5.3L

  • The P1682 is for the ignition switch or low battery and the P0443 is for the EVAP Purge Solenoid. Does the engine cranks when you try to start the engine? or no crank when you turn the ignition switch?

  • Engine trys to crank but no start, also seems to do it more when its warmer outside or the car is to warm

  • and the EVAP Purge Solenoid was replaced less than a week ago. we have noticed that our car does not like any other brand other than Acdelco or GM parts

  • Engine trys to crank but no start, also seems to do it more when its warmer outside or the car is to warm

    I would start by checking the battery voltage. Make sure the the battery terminals (connectors) are clean and tight. Low battery voltage or loose or dirty terminal will cause a no start problem and set the P1682 code.

  • I have a 2007 GMC Canyon 2.9 L 4 cylinder 2 wheel drive 1682 code I have replaced the throttle body all four spark plugs are for coil packs and the gas pedal throttle position sensor and there is absolutely no response whenever I press the gas pedal it will start fine and stay turned on idling but when you press the gas pedal nothing happens it does not rev up the idle at all., and it does sound like it's missing unhesitating rough idle off and on when he's trying to relearn itself but gas pedal does not do nothing it will not rev up turn on sometimes it turns off but you can turn it back on. I am also pulling a p449 code purge value silicone I replaced it about 2 years ago. Plzzzzzz help please please please please.

  • Have you try clearing the code? how long it takes for the codes to come back?
    Unfortunately, I never had that problem before, but I found 4 instances in a national database of repairs for your model and year. On all 4 vehicles with the same codes P0449 and P1682 codes, the problem was the EVAP Canister Vent Solenoid. You could try disconnecting the Solenoid, to see if that makes any difference.

  • CODE P1682: (accompanied by P2534 low voltage detected and REDUCED ENGINE POWER message)
    Here's what I found.........
    2017 Silverado 2500HD pickup 6.0L/ cranked fine, no start.
    3 BASICS....air, fuel, spark.
    AIR? Yep
    FUEL? Pressure at the rail/ Yep........Injected/ Nope..(dry spark plugs...diagnosed as no injector pulse)
    SPARK? Nope
    So no spark and no injection pulse. These are BOTH controlled by the ECM (computer) using cam and crankshaft position sensor inputs. However, no cam or crank sensor codes were present. So i put those possibilities aside temporarily. Back to the ECM. Research showed that it has TWO sources of power from the ignition switch...... located and checked each fuse. Both fuses good. Check for power at fuses with key on and cranking as well. AHA!! One circuit good, the other did not have power. [This is where it helps to have a wiring schematic or someone with repair shop databases on code issues] . The second circuit fuse happened to be indirectly powered by the POWERTRAIN RELAY located adjacent to it. I swapped it out with an identical relay from the "headlight control" circuit to test it. SUCCESS!!
    Engine ran rough until the P1682 code was cleared from memory.

  • Correction......2007 not 2017 model year

  • Great!! Thank you for sharing!!

    According to a national database of repairs for your mode and year, here is the list of the most common causes for the code and symptoms you have:

    - Ignition Switch
    - Battery
    - Powertrain Control Module

  • Did you ever figure out the problem? Having same issues!

  • You may have water entering the fuse box. There is a factory service bulletin for this issue. check "Tech Notes" above, we have updated the information.

  • 2007 GMC ENVOY DENALI THREW CODE P1682!
    I CHANGED THE IGNITION ONE SWITCH CIRCUIT 2 UNDER COLUMN BUT DIDN'T FIX IT UGH WHAT OR WHERE ELSE CAN I CHECK? I CAN CRANK IT AND GO UPTOWN WHEN I GET BACK INTO CRANK IT UP IT TURNED OVER BUT IT WON'T START JUST LIKE YESTERDAY WAS AT THE DRIVE-THRU OF STARBUCKS AND IT JUST CUT OFF WOULDN'T CRANK BACK FOR HOURS AND HOURS LATER

  • David I’m having the same problem, did you ever find the problem?

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