What is electronic spark timing?
The Electronic Spark Control, also called the Knock Sensor, is an electronic device built by General Motors to help regulate the timing inside of the engine. Outside factors such as the humidity or altitude where the engine is operating can also cause timing issues.
How do you test an electronic ignition module?
Connect the ground lead from the 12-volt test light to the negative terminal on the ignition coil. Have your partner crank the engine over several times. Your test light should flicker on and off. If so, your module is working properly and no further testing is necessary.
How do you test a spark control module?
How to Test an Ignition Control Module
- Remove one plug wire at the spark plug and insert an old spark plug into the end of the plug boot.
- Check for voltage at the coil positive terminal when the ignition key is on.
- Locate the ignition module positive (+) wire.
- Locate the ignition module negative (-) wire.
When to use code 42 electronic spark timing circuit?
Code 42 – Electronic Spark Timing Circuit (EST) Circuit Description. When the system is running on the Ignition Module, that is, no voltage on the by-pass line, the Ignition Module grounds the EST signal. The ECM expects to see no voltage on the EST line during this condition.
How does the ignition module control the timing?
During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then “tells” the ignition module via the EST circuit.
How does a GM Electronic spark control module work?
Once the sensors of the Electronic Spark Control system have detected a vibration, they send an electronic signal to the powertrain control module. This module is essentially a small computer, and can determine the exact location of the engine knock.