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.
System Operation
Electronic Spark Control (ESC) circuitry of the ECM retards ignition timing in response to engine detonation. A detonation sensor detects engine knock. The ECM uses detonation sensor inputs to retard ignition timing. A 5-volt reference signal is sent from the ECM to the detonation sensor. ECM internal circuitry reduces the 5-volt signal to 2.5 volts. If engine knock is detected, detonation sensor sends an AC voltage back to the ECM. Amplitude and frequency of AC signal depends on amount of engine knock present. ECM senses AC voltage and retard ignition timing.
A code 43 will be set if the ECM senses a detonation sensor voltage signal above 3.5 volts (shorted to ground), or below 1.5 volts (open circuit), for about .6 seconds. A code 43 can also be set if the detonation sensor produces an AC signal longer than 3.7 seconds during a 3.9 second period.
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.