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.
Chart B-7, BCM-To-Cps Wake-Up Signal Problem
You are at this chart because odometer, with key on, read all 8's, was blank, high beams would not cycle, courtesy lights would not turn on, but lights on chime would sound when activated. These symptoms indicate a loss of 7 volts from Central Power Supply (CPS) to data network components, used to power the microprocessor chip, or CPS has lost system wake-up signal from BCM, which is used to turn on 7-volt power supply.
- This checks circuit No. 555, CPS wake-up signal, a short to ground, a fault in BCM or BCM connector, or a bad CPS.
- This checks an open in circuit No. 555.
- This checks an open circuit in CPS ground, which will disable 7-volt power supply.
- This checks short to ground in each 7-volt circuit from CPS, a faulty component in network or a faulty CPS.
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.