P1682 on RAM: How to Diagnose & Fix
Ignition 1 Switch Circuit 2
1 RAM model · 1 documented issue · $100-$400 repair
P1682 on RAM by model: symptoms, diagnosis and fix
Rams with the Sentry Key Immobilizer Module (SKIM/WCM) can lock out the fuel injectors if the module fails to read a valid transponder key. The engine cranks, fires for ~2 seconds, then dies, and the security/theft light stays on or blinks. Causes include a failing SKIM/WCM, a damaged antenna ring around the ignition lock, a worn transponder chip in the key, or wiring/connector corrosion.
Common Symptoms
- Engine cranks, starts for ~2 seconds, then stalls
- Security/theft light on solid or blinking
- Intermittent no-start that clears after re-inserting key
- No-start with a worn or non-transponder key
How to Fix
Read the security light while cranking (blinking = SKIM lockout). Diagnose with a scan tool that can access SKIM (basic code readers can't). Fix per cause: reprogram/relearn keys, replace the antenna ring, or replace and re-flash the SKIM/WCM (dealer or locksmith with the PIN). Verify battery/ground first. Typical $100-$400 depending on module vs. key relearn.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Ilco Y160-PT 4D-64 transponder key blank
2002-2005 Dodge Ram 1500 as explicitly listed; must be cut to the vehicle and programmed. With two valid keys, some builds support owner programming; otherwise use a locksmith/dealer.
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Sources for this issue (2)
P1682 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P1682 mean on a RAM?
P1682 stands for "Ignition 1 Switch Circuit 2." A manufacturer-specific code used primarily by GM (Chevrolet, GMC, Buick, Cadillac), also listed in GM service data as "Driver 5 Line 2." The engine control module is fed by two separate ignition 1 voltage circuits - one from the ignition switch and one from the run/crank or powertrain relay through a fuse - and P1682 sets when the voltage difference between them exceeds the allowed limit. Because those feeds power the throttle actuator control circuits, this code often accompanies reduced-power mode, a crank-no-start, a no-crank condition, or a stall. On RAM it is documented across 1 model: 1500.
What are the most common causes of P1682?
The most common causes of P1682 are: Failed underhood fuse block / relay center (a very commonly reported cause), Worn or failing ignition switch, Blown fuse or failed run/crank or powertrain relay, Corroded, loose, or damaged ignition-feed connectors, Open or high-resistance wiring in either ignition 1 circuit, Poor ECM ground or corroded ground strap, Faulty engine control module (diagnose last). The specific cause varies by vehicle.
How much does it cost to fix P1682 on a RAM?
Published repair estimates on RAM range from $100 to $400 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P1682 on a different make?
View P1682 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.