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.
Circuit Description
Modules that are connected to the CAN serial data circuits monitor each other for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. the modules have prerecorded information about messages that are exchanged on the serial data circuits. The supervised and periodic messages are used by the receiving module as an availability, and state of health indicator from the transmitting module. If the engine control module (ECM) detects a message that indicates a loss of communication, invalid or corrupted serial data, or an active malfunction in the transmission control module (TCM), that requires ECM intervention, DTC P0701 sets
NO RELATED
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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.