Engine Controls - TEC/Crankshaft Speed

Model Sedona[VQ], Sorento[BL], Amanti[GH]

Group Fuel system(14)

Number KT2006122602

Date Friday January 05, 2007

Area N. America

Subject
Tooth Error Correction (TEC) learn for 3.8L Delph Engine Management

- Description

Tooth Error Correction, or TEC, is a learned algorithm used to compensate for variations in rotational speed of the crankshaft and target wheel (flywheel) due to manufacturing tolerances. Additionally, manufacturing tolerance of any rotational component that could affect crankshaft rotational speeds, such as the transmission torque converter, are also learned. Without TEC learned algorithm compensation, cylinder misfire detection can be compromised.

TEC for the most part is learned without having to perform any learn procedure, and is relearned or updated on a regular basis when specific engine operation conditions (enabling criteria) are met. Once this occurs, TEC is saved in non-volatile memory and cannot be erased. The TEC LEARN parameter on the Global Diagnostic System (GDS) changes from NO to YES. This being said, any component changed that could affect TEC, makes cylinder misfire detection suspect until TEC relearns, even though TEC on GDS shows YES.

TEC can be forced to learn, allowing technicians to assure that TEC is not a contributing factor to false cylinder misfire detection.

TEC is learned:

^ Over a period of 60 seconds of accumulated DFCO (Decel Fuel Cut Off)

^ Between 1500 and 4000 RPM

^ Between 32°F and 230°F Coolant Temp

^ No current or pending DTC's

To force TEC to occur, drive the vehicle in a manner that will allow these stated conditions to be met. This can easily be done by driving a warmed-up vehicle in manual 2nd gear, raising the engine speed to just above 4000 RPM, then removing your foot completely from the accelerator pedal until the engine speed drops to just below 1500 RPM. Repeat this procedure until 60 plus seconds of accumulated DFCO has occurred.

Forced TEC should be performed after any of the following components have been changed:

^ PCM

^ Crankshaft Position Sensor

^ Flywheel / Flex plate / Drive plate

^ Crankshaft / Engine Assy

^ Transmission Assy

^ Harmonic Balancer

Note:
GDS Units must be updated to version 1.09 or higher to support the latest version of the TEC Learn parameter. The TEC Learn parameter is available in the Current Data function of the Engine System. THE TEC LEARN PARAMETER SHOULD BE CHECKED AT KEY ON, ENGINE OFF.

TEC LEARN parameter is only supported on the GDS.