What Is P1682?
P1682 is a General Motors-specific diagnostic trouble code that signals a problem with the Ignition 1 Switch Circuit 2. This code means your vehicle’s onboard diagnostic system has detected an electrical fault in the secondary ignition switch circuit. Unlike generic OBD-II codes, P1682 is proprietary to GM vehicles and indicates a serious electrical issue that can affect multiple vehicle systems simultaneously.
The ignition switch is a critical component that controls power distribution to essential systems including the engine, steering, brakes, and airbags. When the P1682 code is triggered, it means the vehicle’s computer has lost proper signal from the ignition switch circuit, which can have serious safety implications.
What Does P1682 Mean?
The P1682 code specifically refers to “Ignition 1 Switch Circuit 2” on GM vehicles. This is the secondary circuit within the ignition switch assembly that provides power to various vehicle systems. When this circuit fails or becomes unstable, the engine control module (ECM) detects the fault and stores the code.
The ignition switch in modern GM vehicles uses multiple circuits to distribute power safely. Circuit 2 is responsible for powering specific systems that need to remain active even when the engine is off (like the airbag system and power steering control modules). When this circuit malfunctions, the vehicle’s safety systems can be compromised.
Important Note: P1682 is frequently associated with a known GM recall affecting millions of vehicles, particularly certain model years of Chevrolet Cobalt, Saturn Ion, and other GM vehicles. If your vehicle matches the recall criteria, you should contact your GM dealership immediately for a free replacement.
Common Symptoms of P1682
- Multiple Warning Lights: Check Engine Light, Airbag Light, and other warning indicators illuminated simultaneously
- Engine Stalling: Engine may stall unexpectedly while driving, especially during turns or low-speed maneuvers
- Loss of Power Steering: Power steering may cut out intermittently or completely, making the vehicle difficult to steer
- Airbag System Malfunction: Airbag warning light illuminates, indicating the airbag system is not functional
- Electrical System Instability: Dashboard lights flicker, radio cuts out, or other electrical components behave erratically
- Difficulty Starting: Engine cranks slowly or fails to start reliably
- Loss of Gauges: Instrument cluster may go dark or display erratic readings
- Intermittent Issues: Problems may come and go, especially when turning the steering wheel
Possible Causes (Ranked by Frequency)
1. Ignition Switch Electrical Failure (Most Common)
The ignition switch itself is the most likely culprit. Over time, the internal contacts within the switch can wear, corrode, or fail electrically. This is especially common in older GM vehicles or those with high mileage. The switch may have internal arcing or broken connections that prevent proper circuit completion.
2. GM Ignition Switch Recall Issue
Many P1682 codes are directly related to a major GM recall. Certain ignition switches were found to have a design defect where the switch could slip out of the “Run” position, cutting power to the engine and other critical systems while driving. This is a critical safety issue that GM addressed through recalls on millions of vehicles. Check your vehicle’s recall status immediately.
3. Damaged Wiring in Steering Column
The wiring harness that connects the ignition switch to the vehicle’s electrical system runs through the steering column. This wiring can become damaged from repeated steering wheel movement, impact, or age. Broken, pinched, or abraded wires will cause circuit 2 to fail intermittently or completely.
4. Worn Ignition Cylinder
If the ignition cylinder (the part where you insert the key) is worn, it may not properly engage the switch contacts. This wear can cause intermittent electrical connection loss, particularly when the key is turned or the steering wheel is moved.
5. Corroded or Loose Connectors
The electrical connectors at the ignition switch can corrode or loosen over time, especially in vehicles exposed to moisture, salt, or extreme temperatures. Corrosion on connector pins prevents proper electrical contact, while loose connectors cause intermittent circuit failures.
6. Defective Steering Column Switch Assembly
In some cases, additional switches in the steering column (like the turn signal or wiper switches) can fail and affect the ignition circuit through shared wiring or connector issues.
Diagnostic Steps
Step 1: Check for Recalls
Before proceeding with any diagnosis, visit the NHTSA website (nhtsa.gov) or your GM dealership and check if your vehicle has an open recall related to the ignition switch. Enter your VIN to see if you’re eligible for a free replacement. If a recall applies, have it completed immediately—this is often the complete solution.
Step 2: Scan for Additional Codes
Use a GM-compatible diagnostic scanner to read all stored and pending codes. P1682 often appears alongside other codes like U0001 (CAN Bus Off), U0100 (Lost Communication with ECM), or B0001 (Airbag Sensor Circuit). These related codes help pinpoint the exact problem.
Step 3: Visual Inspection
Locate the ignition switch under the steering column (consult your service manual for exact location). Inspect the switch and surrounding wiring for:
- Visible damage, cracks, or burn marks on the switch housing
- Corroded or discolored connectors
- Pinched, cut, or abraded wiring
- Loose connectors or terminals
- Water intrusion or moisture inside the switch assembly
Step 4: Test Ignition Switch Continuity
Using a multimeter set to resistance (ohms) mode, test the continuity of the ignition switch circuits. With the key in different positions (Off, Accessory, Run, Start), you should see specific resistance values. Consult your vehicle’s service manual for exact specifications. Infinite resistance or zero resistance in the wrong position indicates a failed switch.
Step 5: Check Wiring and Connectors
Disconnect the ignition switch connectors and inspect the pins for corrosion or damage. Clean corroded connectors with electrical contact cleaner and a small brush. Test connector pin continuity with a multimeter to ensure proper electrical contact throughout the harness.
Step 6: Test Steering Column Movement
With the ignition in the Run position and the diagnostic scanner connected, gently move the steering wheel through its full range of motion. If the code appears or disappears intermittently during this test, it indicates a wiring problem in the steering column rather than a switch failure.
Step 7: Professional Diagnosis
If basic testing doesn’t reveal the problem, take the vehicle to a GM dealership or qualified technician. They have specialized equipment to test the ignition switch circuits under load and can perform more advanced diagnostics.
Repair Cost Estimates
Ignition Switch Replacement (Most Common Fix):
- Parts Cost: $150–$400
- Labor Cost: $200–$500
- Total: $350–$900
Wiring Harness Repair/Replacement:
- Parts Cost: $200–$600
- Labor Cost: $300–$800
- Total: $500–$1,400
Connector Cleaning/Replacement:
- Parts Cost: $50–$150
- Labor Cost: $100–$300
- Total: $150–$450
Recall Repair (If Applicable):
- Cost: FREE at GM dealership if under recall
Note: Costs vary significantly by vehicle model, year, location, and whether the repair is performed at a dealership or independent shop. Dealerships typically charge more but may offer warranty coverage on the repair.
Can I Still Drive With P1682?
Severity: CRITICAL — DO NOT DRIVE
P1682 is a serious code that indicates a safety-critical system failure. You should not drive the vehicle any further than necessary to reach a repair facility. Here’s why:
- Engine Stalling Risk: The engine can stall unexpectedly at any time, including while driving at highway speeds. This creates an immediate collision hazard.
- Loss of Power Steering: Without power steering, the vehicle becomes extremely difficult to control, especially at low speeds or during parking maneuvers.
- Airbag System Failure: If the airbag system is disabled due to this fault, you have no protection in a crash.
- Brake System Issues: Some GM vehicles may experience brake system problems related to ignition switch failures.
- Recall Safety Issue: If this code is related to the known GM recall, your vehicle has a documented safety defect.
Recommended Action: Have the vehicle towed to a repair facility rather than driving it. If you must drive to a nearby shop, do so slowly on local roads only, avoid highways, and be prepared for sudden engine stalling or power steering loss.
Frequently Asked Questions
Q: Is P1682 the same as the GM ignition switch recall?
A: P1682 is often related to the GM ignition switch recall, but not always. The recall affects specific model years and vehicle models. Check your vehicle’s VIN on the NHTSA website or with your GM dealership to confirm if your vehicle is under recall. If it is, the repair is free. Even if your vehicle isn’t under recall, P1682 still indicates a serious ignition switch problem that requires immediate attention.
Q: Can a bad battery cause P1682?
A: While a severely discharged or failing battery can cause various electrical codes, P1682 specifically indicates an ignition switch circuit problem. However, a weak battery might mask an intermittent ignition switch issue. If you’ve recently replaced the battery and still see P1682, the ignition switch is likely the culprit. If you haven’t replaced the battery recently, have it tested as part of your diagnostic process.
Q: Will clearing the code fix the problem?
A: No. Clearing the P1682 code will only temporarily remove the warning light. The underlying electrical fault will remain, and the code will return within a few driving cycles. The only way to fix P1682 is to repair or replace the faulty ignition switch, wiring, or connectors. Clearing the code without addressing the root cause is dangerous because it masks a critical safety issue.
Q: Can I replace the ignition switch myself?
A: Ignition switch replacement requires removing the steering column cover and working with electrical connectors. If you have automotive experience and the proper tools, you may be able to do this yourself. However, because this is a safety-critical system, professional installation is strongly recommended. Improper installation could leave your vehicle unsafe or create new electrical problems. Additionally, if your vehicle is under recall, GM dealerships perform the replacement free of charge.
Q: Why does P1682 happen more when I turn the steering wheel?
A: If the code appears or worsens when turning the steering wheel, it indicates the problem is likely in the wiring harness that runs through the steering column. As the column moves, damaged or pinched wires lose connection intermittently. This is different from a failed ignition switch itself. A technician can test this by monitoring the code while moving the steering wheel through its full range.