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.
Timing Advance System
ECM controls ignition timing advance based upon sensor input signals that reflect ignition timing needs. If timing problems are experienced, inspect input signals for proper operation. See TIMING ADVANCE SYSTEM INPUT SIGNALS table. To check input signals, see ENGINE SENSORS & SWITCHES or ECM pin voltage charts in PIN VOLTAGE CHART S article in the ENGINE PERFORMANCE Section.
| Application | Model Usage | ||||||
|---|---|---|---|---|---|---|---|
| A/C Clutch Signal | (1) Q45 | ||||||
| Mass Airflow Sensor | G20, J30 & Q45 | ||||||
| Battery Voltage | G20, J30 & Q45 | ||||||
| Crankshaft Position Sensor | G20, J30 & Q45 | ||||||
| Engine (Coolant) Temperature | G20, J30 & Q45 | ||||||
| Ignition (START) Signal | G20, J30 & Q45 | ||||||
| Park/Neutral (Inhibitor) Switch | G20, (2) J30 & (3) Q45 | ||||||
| Power Steering Pressure Switch | J30 & Q45 | ||||||
| Throttle Position Sensor | G20, J30 & Q45 | ||||||
| Closed Throttle Position Switch | J30 & Q45 | ||||||
| Vehicle Speed Sensor | G20, J30 & (2) Q45 | ||||||
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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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