P06AF Torque Management System - Forced Engine Shutdown
OBD-II Trouble Code Technical Description
Torque Management System - Forced Engine Shutdown
What does that mean?
This is a generic diagnostic trouble code (DTC) and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Buick, Cadillac, Chevrolet, GMC, VW, Ford, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
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 malfunction was severe enough that a forced engine shutdown was warranted or perceived. Engine torque management codes are applicable to vehicles with automatic transmissions only.
Torque management systems (used in OBD-II vehicles) are designed to reduce engine torque between automatic transmission shifts. This is necessary to aid in the longevity of the transmission and all other driveline components. The torque management system is activated using the PCM. The PCM calculates data from such sensors as the throttle position sensor (TPS), the transmission input and output speed sensors, and the mass airflow (MAF) sensor to determine the parameters which must be applied to the torque management system. Once a torque management strategy has been configured, the PCM initiates it and repeats it with each applicable drive cycle.
The actual reduction in engine torque is realized when ignition timing is retarded by the PCM. If the PCM perceives that ignition timing cannot be retarded or that engine torque cannot be effectively controlled, to the degree that engine shutdown becomes necessary, a code P06AF may be stored and a service engine soon/malfunction indicator lamp (SES/MIL) illuminated. SES/MIL illumination 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 driver’s would not notice if the torque management system failed to operate and many have reported that they preferred the way their automatic transmission shifted with the torque management disabled. The only reason that I would classify this code as severe is because of the ability of 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:
Engine no-start condition Engine hesitation or miss Engine drivability issues Erratic transmission shift patterns Harsh shiftingWhat are some of the common causes of the code?
Causes for this code may include:
Defective transmission input or output speed sensor Failed torque converter Catastrophic mechanical transmission failure Open or shorted wiring and/or connectors or grounds PCM failure or a PCM programming errorWhat are some P06AF troubleshooting steps?
Any other stored diagnostic codes (especially those related to the torque management system) should be diagnosed and repaired prior to diagnosing the code P06AF.
In order to diagnose a code P06AF, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of reliable vehicle information.
Search for technical service bulletins (TSB) that replicate the code stored, vehicle (year, make, model, and engine), and symptoms exhibited using your vehicle information source. Finding the appropriate TSB, could yield diagnostic information that will point you in the direction of a successful diagnosis.
Connect the scanner to the vehicle diagnostic port and retrieve all stored codes and pertinent freeze frame data. I usually like to write this information down in case the code proves to be an intermittent one. After recording all pertinent data and freeze frame information
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