Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Chart C5 - Electronic Spark Control (ESC) System Check
Electronic spark control is accomplished with a module that sends a voltage signal to ECM. As the knock sensor detects engine knock, voltage from ESC module to ECM is shut off and this signals ECM to retard timing.
- Tests ESC to see if it can detect a knock and can retard spark timing.
- By disconnecting ESC module, ECM sees low voltage at terminal B7 and should retard timing. After approximately 4 seconds, "SERVICE ENGINE SOON" light will come on and Code 43 will be stored.
- Checks for proper voltage output (measured on AC scale) of knock sensor. Low or no voltage would indicate an open circuit to terminal E or faulty sensor.
- Checks to see if constant retard is due to a faulty knock sensor or module, or if a false voltage signal is being transmitted on wire from knock sensor by induction from an adjacent wire, such as a spark plug wire, ignition wire, etc. Re-route wires as necessary.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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