DTC 43

Fig. 032 - WIRING DIAGRAM for Code 43 Electronic Spark Control. VIN 3, VIN 9:

CODE 43, ELECTRONIC SPARK CONTROL (ESC)

Code 43 means the ECM has seen low voltage at CKT 457, terminal B7 in the ECM A-B for connector, longer than 4 seconds with the engine running.
This voltage drops when the ESC module shuts off because it receives a knock signal.

Fig. 031 - Chart - Code 43 Electronic Spark Control:

1. Checks to see if ECM recognizes a problem.
2. The ESC module supplies voltage to the ECM. It should always be over 6 volts unless the system is sensing engine detonation.
3. Checks for intermittent ESC operation. If the voltage is now over 6 volts, it is faulty ESC terminal C connection or ESC module.
4. Checks for grounded ECM.
5. Checks for open ignition circuit.