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.
Starting System
The starting system controls the cranking of the engine. Under normal operation, when the ignition is turned to START, the PCM receives the following inputs:
- Request to crank engine message from the BCM
- PATS enable message from the BCM
- Park or neutral input from the automatic transmission
When the PCM receives the correct inputs, voltage and ground is supplied to the starter relay coil. When the starter relay coil is energized, it provides voltage to the starter solenoid, allowing the starter motor to crank the engine.
The PCM disengages the starter once an engine Revolutions Per Minute (RPM) threshold is reached, a set crank time is exceeded or the ignition is turned off.
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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.