P1698 Code: Here's How to Solve It Fast

The P1698 trouble code is a diagnostic trouble code (DTC) that indicates a communication issue between the Powertrain Control Module (PCM) and the Transmission Control Module (TCM). Specifically, it signifies that the PCM is not receiving messages from the TCM via the Controller Area Network (CAN) bus. This can lead to various symptoms affecting vehicle performance, particularly concerning transmission operation. Understanding this code is crucial for vehicle owners and DIY mechanics, as resolving it often involves diagnosing communication failures within the vehicle's electrical system.

P1698 Code Meaning	P1698 Code Common Causes
No CCD Messages Received From TCM	Faulty TCM or PCM
Bus Communication Failure	Open or shorted wiring in the bus line
Intermittent Signal Loss	Poor electrical connections
Faulty Ground Connections	Low battery voltage or faulty battery
Failed Modules	Corrosion in connectors or terminals

Symptoms of P1698 Code

When the P1698 code is triggered, several symptoms may manifest, indicating a problem with the transmission and its communication with the engine control module. Common symptoms include:

• Check Engine Light: The most noticeable symptom is the illumination of the check engine light on the dashboard.
• Transmission Issues: Drivers may experience hard shifting, slipping gears, or failure to shift at all.
• Speedometer Malfunction: The speedometer may not function correctly, giving inaccurate readings or failing to register speed.
• Rough Idle: The vehicle might exhibit a rough idle condition when starting.
• Gauges Flickering: Instrument cluster gauges may flicker or display erratic behavior.

Technical Explanation of P1698 Code

The P1698 code is primarily associated with the communication network within the vehicle. The PCM and TCM communicate over a data bus using a protocol known as CCD (Chrysler Collision Data). When this communication fails, it can lead to various operational issues.

How Communication Works

The PCM relies on data from the TCM to manage engine performance and transmission functions effectively. If there is a disruption in this communication—due to wiring issues, faulty modules, or poor connections—the PCM will set the P1698 code.

Importance of Proper Communication

Proper communication between these modules is essential for:

• Optimizing Shift Points: The TCM uses data from the PCM to determine when to shift gears based on engine load and speed.
• Maintaining Engine Performance: Without accurate data exchange, engine performance can be adversely affected, leading to increased emissions and reduced fuel efficiency.

Step-by-Step Diagnosis of P1698 Code

Diagnosing a P1698 code involves several steps to identify and rectify the underlying causes effectively.

Step 1: Initial Scan

1. Use an OBD-II scanner to confirm that the P1698 code is present.
2. Check for any accompanying codes that may provide additional context.

Step 2: Visual Inspection

1. Inspect wiring harnesses connecting the PCM and TCM for signs of damage, corrosion, or loose connections.
2. Ensure that all ground connections are secure and free from corrosion.

Step 3: Test Power and Ground

1. With a multimeter, check for proper voltage at the TCM connector.
2. Verify that ground connections are intact and have low resistance.

Step 4: Check Communication Lines

1. Use a scan tool capable of reading live data from both modules.
2. Monitor data flow between the PCM and TCM; look for any discrepancies in expected values.

Step 5: Component Testing

1. If wiring checks out, test both the PCM and TCM for functionality using manufacturer-specific diagnostic tools.
2. Replace any faulty components as necessary.

Solution Methods for P1698 Code

Resolving a P1698 code typically involves addressing communication failures between the PCM and TCM. Here are several methods to consider:

Method 1: Repair Wiring Issues

• Cost Estimate: $50 - $150 depending on labor rates and parts needed.
• Inspect and repair any damaged wires in the bus line connecting the PCM and TCM.

Method 2: Replace Faulty Modules

• Cost Estimate: $300 - $800 for parts (PCM or TCM).
• If either module is determined to be faulty after testing, replace it with an OEM part.

Method 3: Clean Connectors

• Cost Estimate: Minimal; primarily labor if done at home.
• Clean any corroded connectors using electronic cleaner to ensure good electrical contact.

Method 4: Battery Check

• Cost Estimate: $100 - $200 if replacement is needed.
• Ensure that both primary and auxiliary batteries are functioning properly; replace if necessary.

Warnings and Recommendations

• Always disconnect the battery before working on electrical components to prevent shorts or further damage.
• If you are not comfortable performing these diagnostics or repairs yourself, seek assistance from a professional mechanic who has experience with your vehicle's make and model.

Closing Paragraph

The P1698 trouble code can be daunting for many vehicle owners and DIY mechanics due to its implications on transmission performance. However, understanding its meaning, symptoms, technical details, and diagnostic steps can empower you to address this issue effectively. By following systematic troubleshooting methods and being aware of potential pitfalls, you can restore proper communication between your vehicle's control modules and ensure smooth operation once again.

Frequently Asked Questions About P1698

• What does it mean when my car shows a P1698 code?
  The P1698 code indicates that there is no communication between the Powertrain Control Module (PCM) and Transmission Control Module (TCM), which can lead to various transmission issues.
• Can I drive my car with a P1698 code?
  While it may be possible to drive your car with this code present, doing so can result in poor transmission performance and potential further damage.
• How much does it cost to fix a P1698 code?
  The cost can vary widely based on whether it's a simple wiring issue or requires replacing modules; estimates range from $50 for minor repairs up to $800 for module replacements.
• What should I do first if I see a P1698 code?
  The first step is to perform a visual inspection of wiring and connectors related to both the PCM and TCM.
• Is it safe to ignore a P1698 code?
  No, ignoring this code could lead to more severe transmission problems down the line.
• How do I clear a P1698 code?
  You can clear it using an OBD-II scanner after addressing any underlying issues causing it.
• Can bad weather affect my vehicle's ability to communicate?
  Yes, temperature changes can impact electrical connections; intermittent issues may arise in colder conditions.
• When should I seek professional help for a P1698 code?
  If you are unable to diagnose or repair the issue after following basic troubleshooting steps, it's advisable to consult with a professional mechanic.