Here's a breakdown of how to approach troubleshooting and potential fixes:
1. Start with the Basics:
* Check the Transmission Fluid: Low, dirty, or burnt transmission fluid is a very common cause of transmission problems. Check the fluid level (with the engine running and warmed up), and inspect its color and smell. If it's dark brown, burnt smelling, or low, a fluid change and filter replacement are necessary. This is the cheapest and easiest fix to try first.
* Check the Battery and Alternator: A weak battery or alternator can cause voltage issues that affect the transmission's computer. Have these tested at an auto parts store.
* Inspect Wiring and Connectors: Look for any damaged, corroded, or loose wiring harnesses and connectors related to the transmission. Pay close attention to the connectors near the transmission itself.
2. More Advanced Troubleshooting (May Require a Mechanic):
* Advanced Scan Tool: A professional-grade scan tool, not just a code reader, is necessary to get more specific information. These tools can access data from the transmission control module (TCM) and provide more detailed diagnostic trouble codes (DTCs) than just the generic P0700. These DTCs can pinpoint the faulty component.
* Transmission Control Module (TCM) Problems: The TCM itself could be faulty. This requires professional diagnosis and potentially replacement or reprogramming.
* Transmission Solenoids or Valves: Internal transmission problems, such as malfunctioning solenoids or valves, could set the P0700 code. Diagnosis typically requires specialized tools and expertise.
* Speed Sensors: Issues with the vehicle speed sensor (VSS) or output speed sensor (OSS) can affect transmission operation and trigger the P0700 code.
* Shift Linkage or Cables (Automatic): Although less likely, problems with the shift linkage or cables (in the case of a cable-operated automatic transmission) can cause issues.
3. When to See a Mechanic:
If you're not comfortable working on your transmission, or after performing the basic checks and the problem persists, take your vehicle to a qualified mechanic specializing in transmissions. Troubleshooting transmission issues can be complex and often requires specialized equipment and knowledge. Incorrect diagnosis and repair attempts can lead to significant damage and increased repair costs.
Important Note: Ignoring a P0700 code can lead to more severe transmission damage. Addressing the underlying issue promptly is crucial.
