P1678 Code - Immobilizer Powertrain Identification Failed
Quick Answer
The Engine Control Module (ECM), the Powertrain Interface Module (PIM), and the Body Control Module (BCM) are integral part of the vehicle theft deterrent system. Common causes include Deterrent key not programmed to vehicle, Faulty Deterrent key, Faulty ignition switch. 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
- P1678 indicates Immobilizer Powertrain Identification Failed.
- Common causes
- Common causes include Deterrent key not programmed to vehicle, Faulty Deterrent key, Faulty ignition switch.
- 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.
Code P1678 Description
1.When the ignition is turned ON or the door is unlocked by remote key the BCM and the key exchange security data to verify the correct key is used.
2.Once the correct key has been confirmed and the ignition is turned ON, the PIM and BCM exchange data to confirm the correct BCM and PIM is being used.
3.Once the correct key, BCM, and PIM is confirmed, the PIM and ECM exchange data to allow the vehicle to start.
4.The data exchange processes conducted use various encrypted data exchanges between each of the devices.
What are the Possible Causes of the DTC P1678?
- Deterrent key not programmed to vehicle
- Faulty Deterrent key
- Faulty ignition switch
- Poor electrical connection for Deterrent circuit components
How to Fix the DTC P1678?
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.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1678 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.
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Information for Specific Makes
- P1678 Acura — ABS/TCS Control Module Communication Malfunction
- P1678 Audi — ETS Warning Lamp Circuit Shot To Ground
- P1678 Buick — Immobilizer Powertrain Identification Failed
- P1678 Cadillac — Immobilizer Powertrain Identification Failed
- P1678 Chevrolet — Immobilizer Powertrain Identification Failed
- P1678 GMC — Immobilizer Powertrain Identification Failed
- P1678 Honda — ABS/TCS Control Module Communication Malfunction
- P1678 Pontiac — Immobilizer Powertrain Identification Failed
- P1678 Saturn — Immobilizer Powertrain Identification Failed
- P1678 Volkswagen — ETS Warning Lamp Circuit Shot To Ground
Frequently Asked Questions about P1678 Code
1. What are the common symptoms of OBDII code P1678 (Immobilizer Powertrain Identification Failed)?
When this code is triggered, you may experience issues with starting your vehicle, engine stalling, or the immobilizer system preventing the engine from running.
2. What are the possible causes of OBDII code P1678?
The main causes of this code include a faulty immobilizer system, issues with the powertrain control module (PCM), wiring problems, or a malfunctioning key fob.
3. How can I diagnose the cause of OBDII code P1678?
Diagnosing this code typically involves checking the immobilizer system, inspecting the wiring for any damage or loose connections, and using a diagnostic scanner to read the trouble codes stored in the PCM.
4. Can I still drive my vehicle with OBDII code P1678 present?
It is not recommended to drive your vehicle with this code present, as it may lead to unexpected engine stalling or starting issues, which can pose a safety risk.
5. How can I repair OBDII code P1678?
Repairing this code usually involves addressing the root cause, such as repairing or replacing the immobilizer system components, fixing wiring issues, or reprogramming the PCM to recognize the immobilizer.
6. Can a DIY enthusiast fix OBDII code P1678 at home?
While some basic troubleshooting steps can be performed at home, diagnosing and repairing this code may require specialized tools and knowledge, so it's recommended to seek professional help for an accurate fix.
7. Will resetting the PCM clear OBDII code P1678?
Resetting the PCM may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to return once the problem is detected again.
8. How much does it typically cost to repair OBDII code P1678?
The cost of repairing this code can vary depending on the cause and the extent of repairs needed. It's advisable to get a diagnostic assessment from a qualified mechanic to determine the exact cost.
9. Can extreme weather conditions trigger OBDII code P1678?
Extreme weather conditions can potentially affect the performance of the immobilizer system or other related components, leading to the triggering of this code.
10. Is OBDII code P1678 specific to certain vehicle makes or models?
While this code is related to immobilizer and powertrain identification issues, it can be found in various vehicle makes and models equipped with OBDII systems.
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