DTC 43

Code 43 - Electronic Spark Control (ESC):

Code 43 - Electronic Spark Control (ESC):

CODE 43 - ELECTRONIC SPARK CONTROL (ESC)

Circuit Description:

Code 43 says that the Electronic Spark Control (ESC) retard signal has been seen by the ECM for too long a period of time. When voltage at Terminal "L" at the ECM is low, spark is retarded. Normal voltage in non-retard mode is about 7.5V or more.

Test Description:

1. Normal voltage would be over 7.5 volts. If 7.5 volts is present at Term. "L", the reason for a Code 43 is a poor connection to ECM or faulty ECM.

2. Over 6 volts indicates an overly sensitive knock sensor or controller, or noise in the engine that fools the knock sensor.

3. Checks for grounded ECM.


4. Checks for an open in wire from ESC to ECM. If over 6 volts was obtained at Term. "C" of the ESC, the fault is an open to Term. "L" of ECM.


5. Checks for proper 12V ignition source to ESC Term. "B". Term, "B" should be battery voltage.


6. Checks to see if spark retard is due to engine knock or a faulty knock sensor. If by disconnecting the knock sensor spark advances, fault is in engine "noise" or sensor. Normally no increase would be noted.


7. Checks to see if spark retard is due to "noise" on ESC to knock sensor line or a faulty ESC controller. By removing terminal "E" from the connector, the determination can be made. If spark advances, check for improper routing of knock sensor signal wire.