The OBD2 code P0700 is a common trouble code that can appear in Chrysler vehicles, signaling a problem within the transmission control system. While it might seem daunting, understanding what this code means and the potential fixes can empower you to address the issue effectively. This guide breaks down the P0700 code specifically for Chrysler owners, drawing on real-world experiences to help you diagnose and resolve the problem.
Decoding the P0700 Code: Transmission Control System Malfunction
The P0700 code technically stands for “Transmission Control System Malfunction.” It’s not a direct indicator of a specific component failure, but rather a general alert that the Powertrain Control Module (PCM) has detected an issue within the Transmission Control Module (TCM). Think of it as a check engine light specifically for your transmission. When the PCM logs a P0700, it means the TCM has identified a problem and has likely stored additional, more specific trouble codes within its own system.
Symptoms Associated with the P0700 Code in Chrysler Vehicles
Experiencing a P0700 code in your Chrysler can manifest in various ways. Some common symptoms include:
- Check Engine Light: This is the most obvious sign, as the P0700 code triggers the Malfunction Indicator Lamp (MIL) or check engine light on your dashboard.
- Transmission Shifting Problems: You might notice your Chrysler shifting harder than usual, hesitating between gears, or getting stuck in a particular gear (like second gear).
- Limited Gear Functionality: In some cases, the transmission might be limited to only a couple of gears, impacting acceleration and top speed.
- Speedometer Issues (Potentially): While less common with P0700 alone, if the issue involves sensors, you might see erratic speedometer readings, though this is more indicative of specific sensor failures.
It’s important to note that the severity of these symptoms can vary. Some drivers may only experience the check engine light and subtle shifting changes, while others might encounter more pronounced transmission problems.
Potential Causes of the P0700 Code in Chryslers
Pinpointing the exact cause of a P0700 code requires further investigation, but common culprits in Chrysler vehicles include:
- Faulty Transmission Input or Output Sensors: These sensors monitor the speed of the transmission’s input and output shafts. If they fail or become erratic, it can trigger a P0700 code and shifting problems.
- Relay Issues: A malfunctioning TCM relay can disrupt power supply to the transmission control system, leading to various issues, including the P0700 code.
- Transmission Control Module (TCM) Problems: While less frequent than sensor or relay issues, the TCM itself can fail or develop internal faults, causing a P0700 code.
- Wiring and Connection Problems: Loose, corroded, or damaged wiring and connectors in the transmission control system can also lead to malfunctions and trigger the P0700 code.
- Low Transmission Fluid or Fluid Issues: Although not directly triggering P0700, low or contaminated transmission fluid can exacerbate existing issues or contribute to transmission problems that indirectly cause the code.
Diagnosing and Addressing the P0700 Code: DIY Steps and Professional Help
When faced with a P0700 code on your Chrysler, here’s a step-by-step approach to diagnosis and repair:
1. Retrieve Stored TCM Codes
The P0700 code is just the starting point. You need to retrieve the more specific codes stored within the TCM. While a generic OBD2 scanner will read the P0700 from the PCM, you often need a more advanced scanner capable of accessing the TCM to read these additional codes. Many auto parts stores or repair shops offer free code scanning services.
2. Initial Checks: Fuses and Relays
Based on experiences shared by Chrysler owners, a simple first step is to check the TCM fuse and relay.
- Locate the Power Distribution Center (PDC): This is typically under the hood, and the owner’s manual will show its exact location and fuse/relay layout.
- Identify TCM and Starter Relays: These relays are often identical and located near each other in the PDC.
- Relay Swap Test (Caution Advised): As suggested in some forums, you can temporarily swap the TCM relay with the starter relay to see if it resolves the issue. Important: This is a troubleshooting step, not a permanent fix. If swapping relays makes the problem disappear, replace the TCM relay with a new one of the correct type immediately.
- Check the TCM Fuse: Inspect the TCM fuse in the PDC for any signs of being blown. Replace it with a new fuse of the correct amperage if necessary.
The location of the Power Distribution Center (PDC) under the hood of a Chrysler vehicle, often used for checking fuses and relays related to the transmission control module.
3. Evaluate Transmission Sensor Function
If relay and fuse checks don’t resolve the P0700 code, faulty input or output sensors are common suspects, especially if you experience shifting problems.
- Input vs. Output Sensor: If your speedometer is still working correctly when the transmission issue occurs, the input sensor is more likely the culprit. If the speedometer also malfunctions, suspect the output sensor.
- Location: These sensors are typically located on the driver’s side of the transmission case.
- Replacement: Replacing these sensors is often a DIY-friendly task for those with some mechanical aptitude. They are usually held in place by a single bolt or clip and have an electrical connector. Disconnect the connector, remove the sensor, and install the new one, ensuring the connector is securely attached.
4. When to Seek Professional Diagnostic and Repair
If you’ve tried the fuse/relay checks and sensor replacement (if applicable and comfortable), and the P0700 code persists, it’s time to consult a qualified mechanic. More complex issues like a faulty TCM, internal transmission problems, or wiring harness faults require professional diagnostic tools and expertise.
A mechanic will:
- Perform a thorough diagnostic scan: Using advanced tools to read all TCM codes and analyze transmission system data.
- Inspect wiring and connections: Checking for any electrical issues.
- Test sensor functionality: Verifying the input and output sensors are operating correctly.
- Diagnose potential TCM faults: If other components are ruled out, the TCM itself might need replacement or reprogramming.
- Assess overall transmission health: In some cases, underlying transmission problems might be contributing to the P0700 code.
Maintaining Your Chrysler’s Transmission to Prevent Future Issues
Preventative maintenance is key to minimizing transmission problems and avoiding P0700 codes. Regular transmission fluid changes, following Chrysler’s recommended service intervals, are crucial. Also, be attentive to any unusual shifting behavior and address minor issues promptly before they escalate into more significant problems.
By understanding the P0700 code, its potential causes, and troubleshooting steps, you can approach transmission issues in your Chrysler with greater confidence and work towards a cost-effective and lasting solution.
