Here's a breakdown of possible causes and troubleshooting steps:
* Faulty Sensor Replacement: It's possible one or both of the new sensors are defective. Double-check their installation to ensure they are properly seated and connected. Consider getting them tested (auto parts stores often offer this service) to rule out this possibility.
* Transmission Control Module (TCM) Issues: The TCM receives signals from the speed sensors and other components to control shifting. A faulty TCM can cause erratic shifting or complete failure to shift, even with new sensors. This usually requires professional diagnosis and potentially replacement or repair.
* Transmission Fluid and Filter: Low, dirty, or burnt transmission fluid can severely impact shifting. Check the fluid level; it should be within the specified range on the dipstick (engine running and at operating temperature). If the fluid is dark, smells burnt, or contains debris, a fluid and filter change is urgently needed.
* Solenoids or Valves: Internal transmission solenoids or valves control fluid flow to the clutches and bands, enabling shifting. A faulty solenoid or valve can prevent proper shifting. Diagnosis usually requires specialized tools and knowledge.
* Wiring Harness Problems: Damaged or corroded wiring between the sensors, TCM, and transmission can disrupt signals. Inspect the wiring harness for any damage, especially near the transmission.
* Other Sensors: While you replaced the speed sensors, other sensors can also contribute to transmission problems. The engine speed sensor (sometimes called the crankshaft position sensor) and throttle position sensor are particularly important.
What to do next:
1. Re-check Sensor Installation: Make absolutely sure the new sensors are correctly installed and securely connected.
2. Check Transmission Fluid: Inspect the fluid level and condition. If it's low, dirty, or burnt, have it changed immediately. A low fluid level can cause serious transmission damage.
3. Obtain Diagnostic Trouble Codes (DTCs): Use an OBD-II scanner to retrieve the DTCs stored in the car's computer. These codes will pinpoint the likely cause of the CEL and provide more specific information for diagnosis. Auto parts stores often offer free code scanning.
4. Professional Diagnosis: Given that the problem persists after replacing the sensors, it's highly recommended to take your Stratus to a qualified transmission specialist or mechanic for a proper diagnosis. Trying to troubleshoot this further without specialized tools and knowledge could lead to more damage and costly repairs.
Ignoring a persistent transmission problem can lead to catastrophic failure, so prompt professional attention is vital.
