P1682 – Driver 5 Line 2 (GM)
Last Updated 2022-10-12
Automobile Repair Shop Owner
|Code||Fault Location||Probable Cause|
|P1682|| P1682 – Driver 5 Line 2 (GM) |
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|Ignition switch, fuses, PCM relays|
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Manufacturer Specific Definitions for P1682
|Acura||AT to ECM - signal A - input high|
|Audi||CAN data bus, ABS - implausible signal|
|Buick||Engine control module (ECM) -ignitionpower supply less than 10 V|
|Cadillac||Engine control (EC) relay/starter motor relay voltage correlation malfunction|
|Chevrolet||Engine control module (ECM) -ignition power supply variation|
|Chrysler||Alternator -voltage low|
|Citroen||Metering Oil Pump Malfunction|
|Dodge||Altemator -voltage low|
|Gmc||Engine control module (ECM) -ignition powersupply less than 10 V|
|Gm||Ignition 1 Switch Circuit 2|
|Honda||AT to ECM- signal A- voltage high|
|Hummer||Throttle control module/engine control module (ECM) -ignition power supply variation|
|Isuzu||Throttle control module/engine control module (ECM) – ignition power supply variation|
|Jeep||Alternator -voltage low|
|Kenworth||P1682 - Oil level high side driver open circuit|
|Oldsmobile||Engine control module (ECM), ignition supply voltage|
|Peterbilt||P1682 - Oil level high side driver open circuit|
|Peugeot||Metering Oil Pump Malfunction|
|Plymouth||Alternator -voltage low|
|Pontiac||Engine control (EC) relay/starter motor relay – voltage correlation malfunction|
|Ram||Altemator -voltage low|
|Saab||Engine control module (ECM) – ignition power supply less than 10 V|
|Saturn||Engine control module (ECM), ignition supply voltage|
|Volkswagen||CAN data bus, ABS - implausible signal|
Table of Contents
- What Does Code P1682 Mean?
- Where is the P1682 sensor located?
- What are the common causes of code P1682?
- What are the symptoms of code P1682?
- Get Help with P1682
What Does Code P1682 Mean?
OBD II fault code P1682 is a manufacturer-specific trouble code that is defined by carmaker General Motors as “Driver 5 Line 2” and is set when the PCM (Powertrain Control Module) detects a difference in voltage that exceeds a maximum allowable threshold between two circuits that supplies it with battery voltage.
NOTE: While most sources, including official GM sources, list code P1682 with the definition “Driver 5 Line 2”, many online non-official GM sources list this code as P1682 – “Ignition 1 Switch Circuit 2”. In practice, the latter definition describes the same problem as the former. Thus, from a diagnostic perspective, the two definitions are interchangeable.
Unlike almost all other manufacturers that use a single circuit to supply power to the PCM, General Motors products use two circuits to supply the PCM with battery power. One circuit passes through the ignition switch and a relay to the PCM to supply current to all internal circuits associated with the TAC (Throttle Actuator Control) system. The second circuit passes through the run/crank relay and a fuse to supply current to all other circuits in the PCM.
In GM-speak, these two circuits are known as Circuit 1 and Circuit 2, respectively, and in a fully functional system, the current in the two circuits will be equal at all times. However, GM vehicles made between about 2004 and 2015 were known to be fitted with poorly designed ignition switches, and as a result, ignition switch failures were common on vehicles that included many Buick, Cadillac, Chevrolet, GMC, Hummer, Isuzu, Oldsmobile, Pontiac, and Saturn models.
The practical effect of ignition switch failures on these vehicles was that the difference in voltage between circuits 1 & 2 sometimes exceeded 3 volts for longer than 2 consecutive seconds, which caused code P1682 to set. However, an additional complication was that different circuits were affected at different times on different vehicles, and under different conditions, which sometimes produced a bewildering array of symptoms.
For instance, when circuit 1 failed, the throttle actuator was sometimes disabled, and a no-start condition would result. Similarly, when circuit 2 was affected, the fuel pump was sometimes deprived of power, which also resulted in a no-start condition, although the engine would typically crank normally in both cases, although there are exceptions to this.
While a major recall campaign in 2014/15 appeared to have resolved the problem on most GM products, this code still makes random appearances on post-2015 GM products, with much the same causes and symptoms as on pre-2015 models.
Where is the P1682 sensor located?
This image shows a comparison between the poorly designed part (at the top) in GM ignition switches and the redesigned part (at the bottom) that largely corrected the overall design problem.
What are the common causes of code P1682?
Causes of code P1682 are similar on all GM products and could include one or more of the following-
- Failed, failing, or defective ignition switch (Most common)
- Defective fuses or fuse box. Note that under some conditions, such as when the vehicle had been parked in the sun, the fuse boxes on some models would deform, which often caused wiring connections in the fuse box to break or lose contact. This particular issue is known to affect Chevy Trailblazer, GMC Envoy, and Chevy SSR models
- Failed, defective, or malfunctioning PCM relays. Note that in cases where an ignition switch failure affected circuit 1, the reduced power feed to this relay often caused contacts in the relay to arc and burn
- Failed, defective, or malfunctioning fuel pumps, as the result of ignition switch failures affecting circuit 2
- Failed or failing PCM, but note that this code often mimics the effects of a failed PCM or corrupted software. Therefore, the fault must be sought elsewhere before any control module, including the PCM, is condemned
What are the symptoms of code P1682?
Common symptoms of code P1682 are also similar across all affected GM products and could include one or more of the following-
- Stored trouble code and illuminated warning light
- A no-start condition, although the engine would typically crank normally
- In some cases, additional codes may be present along with P1682, depending on whether (or not) the persistent primary problem had caused secondary damage to parts and components
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My 2007 G6 gt 3.9 l just stopped running yesterday it gave me a 1682 code and it giving a radio message says eng power reduced car will crank but not start wat could be the problem and what’s some easy test I can do to find the problem?
Locate the PWR/TRN relay in the underhood fuse block
Remove it and take a look at the connections. If the connections look good and the connectors in the fuse block are not pushed out, replace the PWR/TRN relay.
This should solve the issue. If you still have problems, refer to GM diagnostic document 1759603.
Hope all works out for you.
2014 GMC Acadia, P1682 Driver 5 Line 2. Trac light comes on, service stabilitrak and traction control message flashes, check engine light occasionly comes on, has gone into limp mode when happens, but not always. ECM/TCM/PCM, ignition switch, BCM, all replaced. Been happening for a few months. Was having an occasional starting issue and remote start not working until the BCM was replaced. Usually feel engine jump just before everything happens. My shop and dealership can’t figure it out! Any ideas??
Hello Michelle. I believe one of the root causes is water getting into your under hood fuse block. Causing corrosion and it to arc on terminal 51 of the X3 connector. This is something that needs checked first before replacing the fuse block and connector 51 terminal. Let me know how this goes. Good luck.
Thank you for your response. Since my original post, my vehicle has been at the dealership again and they checked both the inside and outside fuse boxes, neither appeared to have any water damage. Since getting it back it has thrown the same code and issues 3 times. Each time I’m able to reset it by turning it off and back on. It is so frustrating to say the least! Thank you again for your time.
No problem. So, I have an update on this issue. My brother has a 2014 Acadia as well with the same problem. Same p1682 code, same engine power reduced message. I fixed it. It may be the same solution for yours. I found a loose ground wire with some corrosion on it. I cleaned it off, tightened it, and drove it for a trip on the highway. It hasn’t returned. It is ground 114 on the engine block. Hope this helps your Acadia as it did my brother’s.
The next time I take it in for this issue, as I’m sure it will happen again, I will let them know what you said. I sincerely appreciate the advice on the direct location to have them look. I have done so much research on my own trying to help them figure it out because it is beyond frustrating to not know when my car is going to act up. Thankfully, each time it does I can at least get it to reset so I’m not stuck somewhere, but I know that luck will run out eventually. I will update after my next shop visit. The dealership and my shop only want me to drop it off when the issue is active because they cant find the issue when its not actively happening. However, it’s hard to do because everytime I turn the car off & back on the issue is reset, even if the CEL stays on. Of course it never acts up when the shop has it no matter how many times they drive it.
Thanks again, and I’ll definitely keep you posted!!
Sounds great Michelle! Keep me posted.👍yeah, it was very hit and miss with my brother’s Acadia as well.
I have a 2017 chevy silverado 1500 and my truck battery was dead.i changed battery and still did not start.it turns over but does not start.codes P1682 cane up driver 5 line2.when u turn key on I hear a click at pump and filter
Hello, I believe your problem lay within the ecm wiring, or in the ignition relay for the engine control. If you can read the ignition control relay from a scan tool, it should be full battery voltage whenever the key is on. If the voltage reads zero, check the actual voltage at the relay. The X50a relay. Also, check the relay feed wire going to the pcm. The terminal is no. 72 going to the ecm. It is a yellow wire. I believe the problem lays between these components. Best of luck.
I got fault code p1682 and U0109 “Fuel pump control module” I change the fuel pump out still pulling the code, my instrument cluster and radio went out an hour before I shut it off, it would turn over just wouldn’t crank when I tried starting.
Hello Sam. Some problem areas to test are, the power train relay, ecm fuses, ignition fuses, and if those are all good, see if you can communicate with the fuel pump control module. These fuse boxes on these have a tendency to melt if left out in the sun constantly.
2006 GMC Envoy Denali with driver and Lane 5 and 2 coad and will not start at all but the ignition does turn on it just won’t turn over except on occasion then it runs fine
Hello.I believe the correct repair for this issue is to replace the under hood fuse block. Reference to TSB #06-06-04-007.
You mean replace the whole fuse box?
Yes sir. They sell whole fuse blocks with fuses and relays included and already in place.
4.3 chevy pick up. Reduce engine power. Codes are o2 sensor , maf sensor, no power readings at the maf, no throttle actuator percentage on scan tool. Fuel reading only open loop.
Hello Alton. When I’ve dealt with this issue before, it was a blown engine fuse. Check the ecm fuses, engine fuse, and ignition fuses and relays.
07 chevy tahoe my truck will not shut off turn the key off and take it out I have to disconnect battery and take main wire of alternator
Hello Mark. It sounds like maybe a pin is broken on your ignition lock cylinder. Or tumbler. I would look here first.
Chevy Tahoe it won’t even crank
Over how to fix i
Fault code p1682 enjoy car is not starting