P001685 with long crank

Ever turned the key in your car and heard that dreaded whirr... whirr... whirr... before the engine finally coughs to life? That's a long crank, and in the world of automotive diagnostics, it often points to a specific culprit: diagnostic trouble code (DTC) P001685. This code, while seemingly cryptic, is a breadcrumb leading you towards understanding a potential issue with your vehicle's engine timing and its impact on starting. Understanding this code can save you a trip to the mechanic and provide you with the knowledge to communicate effectively if professional help is needed.

What Exactly Does P001685 Mean? Decoding the Code

DTC P001685, in simplified terms, indicates a problem with the correlation between the crankshaft position sensor and the camshaft position sensor. Your engine relies on precise timing between these two components for optimal combustion. The crankshaft position sensor monitors the position and speed of the crankshaft, which is directly connected to the pistons. The camshaft position sensor, on the other hand, monitors the position of the camshaft, which controls the opening and closing of the engine's valves. The Engine Control Unit (ECU), the brain of your car, uses the data from these sensors to orchestrate the fuel injection and ignition timing.

When the ECU detects that the signals from these two sensors are out of sync, it flags the P001685 code. This desynchronization means the ECU is uncertain about the exact position of the pistons and valves, leading to difficulties in starting the engine - hence the "long crank." The specific definition of the code can vary slightly depending on the vehicle manufacturer, but the core issue remains the same: a timing discrepancy.

Why is a Long Crank a Big Deal? More Than Just an Inconvenience

A long crank isn't just annoying; it's a symptom of a potentially larger problem. While you might be tempted to ignore it if the car eventually starts, persistent long cranks can lead to more serious issues down the line.

Increased Wear and Tear: Repeatedly cranking the engine for extended periods puts extra strain on the starter motor, battery, and other engine components. This can shorten their lifespan and lead to premature failure.
Poor Fuel Economy: An engine struggling to start often consumes more fuel during the cranking process. Over time, this can add up and negatively impact your fuel efficiency.
Potential Engine Damage: In severe cases, a timing misalignment can lead to more significant engine damage. If the valves and pistons collide due to incorrect timing, it can result in costly repairs.
Catalytic Converter Issues: Extended cranking can flood the engine with unburnt fuel, which can then damage the catalytic converter. Replacing a catalytic converter is an expensive repair.
Driveability Problems: Even if the car eventually starts, a timing issue can sometimes lead to rough idling, hesitation during acceleration, and overall poor engine performance.

Digging Deeper: Common Causes of P001685

Now that we understand the code and its potential consequences, let's explore the common culprits behind P001685:

Faulty Crankshaft or Camshaft Position Sensor(s): The sensors themselves can fail due to age, damage, or electrical issues. A sensor that is providing inaccurate or intermittent readings will trigger the code.
Timing Chain/Belt Problems: The timing chain or belt connects the crankshaft and camshaft, ensuring they rotate in sync. If the chain or belt is stretched, worn, or has jumped a tooth, it will disrupt the timing and trigger the code. This is more common in vehicles with higher mileage or those that haven't had regular maintenance.
Low Engine Oil Level: Low oil levels can lead to increased friction and wear on engine components, including the timing chain/belt. This can exacerbate timing issues and trigger the code.
Oil Control Valve (OCV) Issues: Some vehicles use Oil Control Valves (OCVs) to regulate oil flow to the camshaft phasers, which control variable valve timing. A malfunctioning OCV can disrupt the timing and trigger the P001685 code.
Wiring or Connector Problems: Damaged, corroded, or loose wiring and connectors to the crankshaft or camshaft position sensors can interfere with the signal transmission and trigger the code.
ECU Problems: While less common, a faulty ECU can sometimes misinterpret the sensor signals and trigger the code. This is usually diagnosed after ruling out other potential causes.
Camshaft Phaser Problems: Camshaft phasers are part of a variable valve timing (VVT) system, which adjusts valve timing for optimal performance. If the phasers are malfunctioning, the timing can be off, leading to the P001685 code.

Diagnosing P001685: A Step-by-Step Approach

Diagnosing P001685 requires a systematic approach to identify the root cause. Here's a general process:

Scan the Vehicle's Computer: Use an OBD-II scanner to confirm the presence of the P001685 code and check for any other related codes. Additional codes can provide valuable clues about the underlying problem.
Visual Inspection: Carefully inspect the wiring and connectors to the crankshaft and camshaft position sensors for any signs of damage, corrosion, or looseness. Also, check the engine oil level.
Sensor Testing: Use a multimeter to test the crankshaft and camshaft position sensors. You can check their resistance and signal output to determine if they are functioning properly. Consult your vehicle's repair manual for specific testing procedures and acceptable values.
Timing Chain/Belt Inspection: This is often the most challenging part of the diagnosis. Inspect the timing chain or belt for wear, stretching, or damage. This may require removing the timing cover for a thorough inspection. Look for signs of wear on the guides and tensioners as well.
Oil Control Valve (OCV) Testing: If your vehicle has OCVs, test their functionality. You can usually do this by checking their resistance and verifying that they are receiving power and ground.
Camshaft Phaser Inspection: Inspect the camshaft phasers for any signs of damage or malfunction. This may require specialized tools and knowledge.
ECU Testing (Last Resort): If all other components check out, the ECU may be the culprit. However, this is rare and usually requires professional diagnostic equipment and expertise to confirm.

Important Note: Diagnosing P001685 can be complex, and some steps require specialized tools and knowledge. If you're not comfortable working on your vehicle's engine, it's best to consult a qualified mechanic.

Fixing the Problem: Potential Solutions

The solution to P001685 depends entirely on the underlying cause. Here are some potential fixes:

Replace a Faulty Sensor: If the crankshaft or camshaft position sensor is faulty, replacing it with a new one is the solution. Ensure you use a high-quality replacement sensor.
Replace the Timing Chain/Belt: If the timing chain or belt is stretched, worn, or damaged, it needs to be replaced. This is a more involved repair that requires careful attention to detail.
Repair Wiring or Connectors: If there are damaged, corroded, or loose wiring or connectors, repair or replace them as needed.
Replace the Oil Control Valve (OCV): If the OCV is malfunctioning, replacing it can resolve the issue.
Replace Camshaft Phasers: If the camshaft phasers are damaged, replacing them will correct the timing issue.
Address Low Oil Levels: Ensure the engine oil level is correct and that there are no leaks.
ECU Repair or Replacement: In rare cases, the ECU may need to be repaired or replaced. This is a complex procedure that should be performed by a qualified technician.

After any repair, it's crucial to clear the P001685 code and retest the system to ensure the problem is resolved.

Preventing P001685: Proactive Maintenance

While some causes of P001685 are unavoidable, there are steps you can take to minimize the risk:

Regular Oil Changes: Maintain proper engine oil levels and adhere to the manufacturer's recommended oil change intervals. This helps to lubricate engine components and prevent wear.
Timing Belt/Chain Replacement: Follow the manufacturer's recommended schedule for timing belt or chain replacement. Replacing these components proactively can prevent catastrophic engine damage.
Regular Inspections: Have your vehicle inspected regularly by a qualified mechanic. This can help identify potential problems before they escalate into more serious issues.
Monitor Engine Performance: Pay attention to any changes in engine performance, such as rough idling, hesitation, or decreased fuel economy. These could be early warning signs of a potential problem.
Use Quality Parts: When replacing any engine components, use high-quality parts from reputable manufacturers. This ensures proper fit and performance.

Frequently Asked Questions

Q: Can I drive my car with a P001685 code? A: It's not recommended. Driving with this code could lead to further engine damage. It's best to get it diagnosed and repaired as soon as possible.
Q: How much does it cost to fix P001685? A: The cost varies widely depending on the cause. A sensor replacement might be a few hundred dollars, while a timing chain replacement could be over a thousand.
Q: Can low oil cause P001685? A: Yes, low oil can contribute to timing chain wear and trigger the code. Maintaining proper oil levels is crucial.
Q: Is P001685 a serious problem? A: Yes, it can be. While seemingly minor, it indicates a timing issue that can lead to significant engine damage if left unaddressed.
Q: Can I fix P001685 myself? A: It depends on your mechanical skills and tools. Some repairs are straightforward, while others require specialized knowledge and equipment.

The Takeaway

Dealing with a P001685 code and a long crank can be frustrating, but understanding the underlying causes and potential solutions empowers you to take control of the situation. Remember to approach the diagnosis systematically and don't hesitate to seek professional help if needed to ensure the problem is resolved correctly.