DTC 43

Code 43 - Electronic Spark Control (ESC):

Wiring Diagram For Code 43 - Electronic Spark Control (ESC):

CODE 43 - ELECTRONIC SPARK CONTROL (ESC)


Circuit Description:

Code 43 means the ECM has been low voltage at CKT 485 terminal B7, for longer than 4 seconds with the engine running.

The voltage drops at terminal B7 when the ESC module shuts off because it receives a knock signal.

This system also performs a functional check once per start up to check the ESC system. To perform this test the ECM will advance the spark when coolant is above 90~C and at W.O.T. The ECM then checks the signal at B7 to see if a knock is detected. The functional check is performed once per start up and if knock is detected when coolant is below 90~C (194~F) the test has passed. If the functional check fails, the "Service Engine Soon" light will remain on until ignition is turned off or until a knock signal is detected.


Test Description:

1. Checks to see if ECM recognizes a problem.

2. This will determine if the system is functioning at this time.

3. The ESC module supplies voltage to the ECM. It should always be over 6 volts unless the system is sensing engine detonation.



4. Checks for intermittent ESC operation. If the voltage is now over 6 volts, it is a faulty ESC terminal "C" connection or ESC module.

5. Checks for grounded ECM.

6. Checks for open ignition circuit.