Diagnostic Aids

Code 43 can be caused by a faulty knock sensor connection at ESC module or ECM. Also, check controller-to-ECM signal line for an open or short to ground.

CODE 43 ECM TERMINAL & CIRCUIT WIRING IDENTIFICATION

Application	ECM Terminal	Wire Color
All With 4L60-E Transmission Knock Signal	B15	Dark Blue
All With 4L80-E Transmission Knock Signal	D5	Dark Blue

Fig 1: CODE 43, Schematic, ESC W/ Spark Control Module

Fig 2: CODE 43, Flowchart, ESC W/ Spark Control Module