Technical Description of OBD-II Trouble Code
Forced Engine Shutdown – Torque Management System
What does that signify?
This is a generic diagnostic trouble code (DTC) that is applicable to many OBD-II vehicles (1996-newer), including vehicles from Buick, Cadillac, Chevrolet, GMC, VW, Ford, etc. The repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
If your OBD-II equipped vehicle has stored a code P06AF, it means that the powertrain control module (PCM) has detected an irregularity in the torque management system. The irregularity was severe enough to warrant or perceive a forced engine shutdown. This code is only applicable to vehicles with automatic transmissions.
Torque management systems in OBD-II vehicles are designed to reduce engine torque during automatic transmission shifts. This is done to prolong the lifespan of the transmission and other driveline components. The torque management system is activated by the PCM, which calculates data from various sensors such as the throttle position sensor (TPS), transmission input and output speed sensors, and mass airflow (MAF) sensor. Once a torque management strategy is configured, the PCM initiates and repeats it with each applicable drive cycle.
The PCM achieves the reduction in engine torque by retarding ignition timing. If the PCM determines that ignition timing cannot be retarded or engine torque cannot be effectively controlled to the extent that engine shutdown becomes necessary, a code P06AF may be stored and the service engine soon/malfunction indicator lamp (SES/MIL) may illuminate. Illumination of the SES/MIL may require multiple ignition cycles with a failure.
What is the severity of this DTC?
Torque reduction systems are not critical to vehicle operation. Most drivers would not notice if the torque management system fails to operate, and many have reported preferring the way their automatic transmission shifts with the torque management disabled. The severity of this code is classified as severe due to the potential for the torque management system to shut down the engine.
What are some of the symptoms of the code?
Symptoms of a P06AF trouble code may include:
What are some of the common causes of the code?
Possible causes for this code may include:
What are some P06AF troubleshooting steps?
Prior to diagnosing the code P06AF, any other stored diagnostic codes (especially those related to the torque management system) should be diagnosed and repaired.
To diagnose a code P06AF, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information.
Using your vehicle information source, search for technical service bulletins (TSB) that match the stored code, vehicle (year, make, model, and engine), and exhibited symptoms. Finding the appropriate TSB may provide diagnostic information to guide you towards a successful diagnosis.
Connect the scanner to the vehicle diagnostic port and retrieve all stored codes and relevant freeze frame data. It is recommended to write down this information in case the code is intermittent. After recording the data and freeze frame information, clear the codes and test drive the vehicle until one of two things occur: the code is restored or the PCM enters readiness mode.
If the PCM enters readiness mode, the code is intermittent, making it more difficult to diagnose. However, if the code is restored, continue with the diagnosis.
Obtain connector face views, connector pinout charts, component locators, wiring diagrams, and diagnostic flow charts specific to the code and vehicle in question using your source of vehicle information.
Visually inspect all related wiring and connectors. Repair or replace any wiring that is cut, burned, or damaged. It is also recommended to check chassis and engine grounds. Use your vehicle information source to obtain ground junction locations for related circuits.
If no other codes are stored and the P06AF code continues to reset, use the DVOM to test controller power supply fuses and relays. Replace any blown fuses, relays, and fusible links as necessary. It is important to test fuses with the circuit loaded to avoid misdiagnosis.
If all controller power and ground circuits are intact and the P06AF code persists, a defective controller or controller programming error may be suspected. Keep in mind that replacing the controller will likely require reprogramming. Reprogrammed controllers may be available through aftermarket sources for some applications, while other vehicles/controllers may require on-board reprogramming that can only be done through a dealership or other qualified source.
Visually inspect system controllers for signs of water, heat, or collision damage. Any controller showing signs of damage should be considered defective.
