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/System Description
The control module has 2 internal 5-volt reference busses called 5-volt reference 1 and 5-volt reference 2. Each reference bus provides 5-volt reference circuits for more than one sensor. Therefore, a fault condition on one 5-volt reference circuit will affect the other 5-volt reference circuits connected to that reference bus. The control module monitors the voltage on the 5-volt reference busses.
The 5-volt reference 1 bus provides 5 volts to the following sensors:
- The manifold absolute pressure (MAP) sensor
- The fuel tank pressure (FTP) sensor
- The accelerator pedal position (APP) sensor 2
- The engine oil pressure (EOP) switch
- The camshaft position (CMP) sensor
The 5-volt reference 2 bus provides 5 volts to the following sensors:
- The APP sensor 1
- The throttle position (TP) sensor 1 and 2
- The air conditioning (A/C) refrigerant pressure sensor
- The crankshaft position (CKP) sensor
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.