A Failed Obdii Test due to a transmission problem can be a costly and frustrating experience. This article explains what Transmission Diagnostic Trouble Codes (DTCs) are, why they cause a failed emissions test, and what your options are if you encounter this issue.
What are Transmission DTCs and Why Do They Cause a Failed OBDII Test?
Your vehicle’s On-board Diagnostics system (OBDII) constantly monitors various components, including the transmission. When a problem is detected within the transmission system, the OBDII system triggers the Malfunction Indicator Lamp (MIL) – often referred to as the “check engine light” – and stores a specific Diagnostic Trouble Code (DTC). These DTCs pinpoint the nature of the problem, aiding mechanics in diagnosis and repair. A transmission DTC can cause a failed OBDII test because transmission problems often lead to increased emissions, exceeding allowed limits.
A variety of issues can trigger a transmission DTC, ranging from minor sensor malfunctions to significant internal damage:
- Faulty Torque Converter Clutch (TCC): The TCC is responsible for locking up the torque converter, improving fuel efficiency at higher speeds. A malfunctioning TCC can lead to slippage and increased emissions.
- Malfunctioning Shift Solenoids: These electronically controlled valves regulate fluid flow within the transmission, controlling gear shifts. A faulty solenoid can result in erratic shifting, poor performance, and increased emissions.
- Transmission Speed Sensors: These sensors monitor the speed of the input and output shafts of the transmission. Inaccurate readings can disrupt proper shifting patterns and affect emissions.
- Low Transmission Fluid: Insufficient fluid levels can cause overheating, damage to internal components, and ultimately, higher emissions.
Repair Costs and Waiver Options for Transmission DTCs
Repairing a transmission problem can be expensive, ranging from $1500 to $3000 or more, depending on the severity of the issue. Sometimes, a simple service like replacing the transmission fluid and filter can resolve the problem. In other cases, more extensive repairs, such as replacing the torque converter or rebuilding the transmission, might be necessary. Because of the potentially high repair costs, some states offer waiver programs to help vehicle owners facing significant expenses.
If you’ve received a failed OBDII test due to a transmission DTC, consider the following:
- Consult a Recognized Emissions Repair Facility (RERF) or Dealership: These certified facilities can accurately diagnose the problem and provide a repair estimate. This documentation is often required for waiver applications.
- Inquire About Waiver Eligibility: Contact your local Department of Public Safety (DPS) or equivalent agency to determine if you qualify for a waiver based on the cost of the required repairs. Remember, only diagnoses and repair estimates from a RERF or dealership are typically accepted.
Engine-Related Issues Mimicking Transmission Problems
It’s important to note that engine problems can sometimes mimic transmission issues. For example, a misfiring engine can disrupt proper shifting and even trigger a transmission DTC. A qualified mechanic at a RERF or dealership will thoroughly inspect your vehicle to ensure the correct diagnosis. This includes checking all electrical circuits and related components to pinpoint the root cause of the problem.
Understanding the Link Between Transmission Problems and Emissions
The transmission is an integral part of your vehicle’s powertrain. Its role in transferring power from the engine to the wheels directly impacts fuel efficiency and emissions output. Therefore, a malfunctioning transmission can lead to a failed OBDII test due to exceeding emissions standards.
