You’re driving to work one morning, and your car won’t start. The security light on your dashboard is flashing, and you’re left wondering what’s going on.
Your vehicle’s onboard computer may have triggered a P1685 code, indicating it’s received an invalid or incorrect key message from the Sentry Key Immobilizer Module (SKIM) system.
This error code is a red flag, suggesting a problem with your vehicle’s security system. But what’s causing it, and how can you get back on the road?
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Key Takeaways
- The P1685 code is triggered when the onboard computer detects an invalid or incorrect key message from the Sentry Key Immobilizer Module (SKIM) system.
- Faulty key transponders, SKIM module malfunctions, wiring issues, and ECM problems can cause the P1685 code to be triggered.
- Symptoms of the P1685 code include engine starting issues, illuminated Security or Key lights, and loss of power or performance.
- To diagnose and repair the issue, identify the root cause, inspect the key transponder, test the SKIM module, and check the wiring between components.
- A diagnostic scan is necessary to identify the root cause of the issue, and factory manuals or online forums can provide valuable resources for troubleshooting and repair.
Code P1685 Description
When your vehicle’s onboard computer detects an invalid or incorrect key message from the Sentry Key Immobilizer Module (SKIM) system, it triggers the P1685 diagnostic trouble code (DTC).
This code is related to your vehicle’s immobilizer system, which is designed to prevent theft.
The SKIM system prevents unauthorized vehicle operation by disabling the engine unless a valid key with the proper transponder is used.
If the engine control module (ECM) receives an incorrect or invalid key message, it triggers the P1685 code and activates a warning light on the dashboard, indicating a potential issue with your vehicle’s security system.
Common Causes of P1685
Faulty key transponders, SKIM module malfunctions, wiring issues, and ECM problems are common culprits behind the P1685 code.
You’ll want to investigate these potential causes to diagnose the issue. Key fob issues, such as a malfunctioning transponder chip, can prevent the SKIM module from receiving the correct signal, triggering the code.
Immobilizer failure, whether due to a faulty SKIM module or ECM issue, can also cause the P1685 code.
Wiring problems between the SKIM module, key transponder, and ECM can also disrupt communication, leading to the code.
Identifying the root cause is vital to resolving the issue.
Symptoms of P1685
Your vehicle’s P1685 code can manifest in several ways, impacting your driving experience.
You may encounter engine starting issues, where your vehicle won’t start or stalls immediately after starting. The Security or Key light on your dashboard may illuminate, indicating immobilizer issues.
In severe cases, your vehicle may become immobilized and unable to operate. You may also experience a loss of power or performance.
These symptoms can be frustrating and disrupt your daily routine. It’s essential to address these vehicle troubles promptly to avoid further complications.
How to Fix P1685
To fix the P1685 code, you’ll need to identify the root cause of the issue, which can be a faulty key transponder, SKIM module malfunction, wiring issues, or an ECM problem.
Start by inspecting the key transponder for damage and testing it to confirm it’s functioning correctly. If the issue persists, test the SKIM module to determine if it’s sending the correct signal to the ECM.
Check the wiring between the SKIM module, key transponder, and ECM for any breaks or damage. If you find a faulty component, replace it – whether it’s a Key Replacement or a Faulty Module.
Diagnostic Scan
When you’re trying to fix the P1685 code, getting a clear picture of what’s going on is vital, and that’s where a diagnostic scan comes in. This scan helps you identify the root cause of the issue, whether it’s a faulty key transponder, SKIM module malfunction, or wiring problems. You’ll need a scan tool that can communicate with your vehicle’s onboard computer.
| Scan Tool | Vehicle Communication | Cost |
|---|---|---|
| OBD-II Scanner | Standard protocol | $20-$50 |
| Advanced Scan Tool | Augmented protocol | $100-$200 |
| Professional Scan Tool | Advanced protocols | $500-$1000 |
Choose a scan tool that fits your needs and budget to get started with diagnosing the P1685 code.
Checking the Key Transponder
The key transponder is a critical component of the SKIM system, and inspecting it’s an essential step in diagnosing the P1685 code.
You’ll want to check the key transponder for any signs of damage or wear. If you’re using a keyless entry system, make sure the transponder chip is functioning correctly.
Try using a spare key to rule out any issues with the key itself. If the spare key works, it could indicate a problem with the original key’s transponder chip.
Inspect the key’s circuit board for any signs of corrosion or damage.
Testing the SKIM Module
You’ll need to test the SKIM module to determine if it’s sending the correct signal to the ECM, which is essential in diagnosing the P1685 code.
To do this, you’ll need to perform Immobilizer testing to check the SKIM functionality. This involves using a scan tool to monitor the SKIM module’s communication with the ECM.
Look for any errors or irregularities in the signal, which could indicate a faulty SKIM module. You can also use a wiring diagram to identify the specific circuit and connector pins related to the SKIM module’s communication with the ECM.
Inspecting the Wiring
Inspect the wiring between the SKIM module, key transponder, and ECM for any signs of damage, corrosion, or wear.
Check for:
- Cracked or broken insulation exposing copper wires
- Corrosion or rust on connectors or terminals
- Pinched or crushed wires under trim or carpets
- Burn marks or signs of overheating
- Loose or faulty connections causing intermittent signals
Look for any signs of wire damage or faulty connections that could be causing the P1685 code.
Make sure to inspect the wiring carefully, as even minor damage can cause issues with the SKIM system.
Replacing Faulty Components
Faulty components in the SKIM system can prevent proper communication between the key transponder, SKIM module, and ECM, triggering the P1685 code. You’ll need to identify and replace the faulty component to resolve the issue. Common faulty components include the key transponder, SKIM module, and wiring.
| Component | Symptoms | Repair/Replace |
|---|---|---|
| Key Transponder | Inability to start the engine, warning lights on the dashboard | Transponder repair or replacement |
| SKIM Module | Engine stalling, loss of power | SKIM module replacement |
| Wiring | Engine starting issues, immobilization | Wiring repair or replacement |
Cost to Fix P1685
The cost to repair a P1685 code can vary widely, depending on the specific cause of the issue and the labor rates in your area.
You’ll want to get a repair estimate from a qualified mechanic to determine the total cost.
Here are some factors that can affect the cost:
- Parts cost: $50 to $200 for a new key transponder or SKIM module
- Labor cost: $100 to $300 for diagnosis and repair
- Insurance coverage: Check if your insurance policy covers repairs related to the immobilizer system
- Location: Labor rates vary by location, so expect higher costs in urban areas
- Complexity: If the issue is complex, you may need to pay more for diagnostic tests and repairs
Additional Resources
You’ve likely gotten a repair estimate for your P1685 code, but now you want to dig deeper and understand the issue better.
For in-depth information, consult factory manuals specific to your vehicle’s make and model. These resources provide detailed diagrams, troubleshooting guides, and repair procedures.
Online forums dedicated to your vehicle’s brand or model can also be a valuable asset. You’ll find discussions, tutorials, and real-world experiences from owners and mechanics who’ve tackled similar issues.
Take advantage of these resources to gain a deeper understanding of your P1685 code and make informed decisions about the repair process.
More OBD-II Codes
| P1686 | P1687 | P1688 | P1689 |
| P1691 | P1695 | P1155 | P1156 |
| P1157 | P1158 | P1159 | P1161 |
| P1163 | P1164 | P1165 | P1170 |
| P1171 | P1185 | P1189 | P1187 |
| P1190 | P1215 | P1216 | P1217 |
Frequently Asked Questions
Can I Drive My Car With a P1685 Code?
You shouldn’t drive your car with a P1685 code, as it affects car security and keyless functionality, potentially causing immobilization, engine stalling, or loss of power, making it unsafe to operate until the issue is resolved.
Will a P1685 Code Cause My Car to Shut off While Driving?
When you’re driving, a faulty key message can cause your car to shut off, especially if the remote start or ignition switch is malfunctioning, leading to a loss of power and potentially stranding you.
Can I Reset the P1685 Code Myself?
Did you know that 1 in 5 car owners experience immobilizer system issues? You can try to reset the P1685 code yourself by attempting key reprogramming or an immobilizer reset, but it’s recommended to consult a professional to avoid further complications.
Will a New Key Fix the P1685 Code Issue?
You may fix the issue with a new key, but it’s not a guarantee. Key replacement and reprogramming might resolve the problem, especially if the transponder chip is faulty, but it’s essential to diagnose the root cause to certify a proper fix.
Can a Faulty ECM Cause Other Issues Besides the P1685 Code?
Like a puzzle with a missing piece, a faulty ECM can cause a cascade of issues beyond the P1685 code, including erratic immobilizer system behavior, faulty fuel injection, and misfiring engines, making it a ticking time bomb for your vehicle’s performance.
Conclusion
You’ve finally diagnosed the pesky P1685 code, but don’t think you’re out of the woods just yet. While a faulty key transponder or SKIM module might be the culprit, it’s just as likely that a more sinister issue lurks in the shadows, threatening to immobilize your vehicle. Don’t let your guard down – get to the root of the problem and take corrective action to guarantee your vehicle’s security system is back on track.
