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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSBMW1993740IL (E32/2) V8-3982CC 4.0L DOHC (M60)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSDESCRIPTION AND OPERATIONENGINE CONTROL SYSTEM INPUTSPOWER SUPPLY
1993 BMW 740iL (E32/2) V8-3982cc 4.0L DOHC (M60)
Power Supply
1993 BMW 740iL (E32/2) V8-3982cc 4.0L DOHC (M60)SECTION Power Supply
BATTERY POWER, KEY ON AND ENGINE MAIN RELAY VOLTAGE SUPPLY INPUTS
The engine control module receives a number of power supply inputs. These inputs provide information as well as operating power for the engine control module.
- KL 30 - Constant battery power: The engine control module requires continual voltage supply from the battery to store system adaptation values and fault codes. It also monitors the voltage level of the power supply as an input signal. If the voltage value weakens below a certain threshold, the engine control module adjusts certain output functions to compensate for the lower voltage value. i.e.: modify pulse width duration of fuel injectors, modify dwell time of ignition, etc.
- KL 15 - Ignition Key On input: The ignition key on input informs the engine control module that the engine is about to be turned on. This input signal is often called the "wake up call". When received, the engine control module provides a ground for the engine control module relay causing the relay to activate.
- KL 15 - Engine Main Relay Power Supply: Once the Engine Control module relay is activated, the closed contacts of the relay provide the operating power for the control module as well as the system components.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.