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.
Powertrain Control Module (PCM)
The PCM is on the CAN and uses this network to communicate with the diagnostic tool. The PCM utilizes an internal termination resistor for normal interface with the CAN. Damage or loss of this termination resistor results in intermittent operation and or failure of the entire CAN. The PCM controls the engine for better fuel economy, emissions control, failure mode detection and storage, all passive anti-theft system (PATS) functions, as well as all 4-wheel drive (4WD) and speed control functions.
For additional 4WD information, refer to FOUR- WHEEL DRIVE SYSTEMS .
For additional speed control information, refer to SPEED CONTROL .
For additional PATS information, refer to ANTI-THEFT - PATS .
See INTRODUCTION - GASOLINE article for diagnosis and testing of the PCM.
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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