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 MANUALSBMW1987L7 (E23) L6-3430CC 3.4L SOHC (M30)REPAIR AND DIAGNOSISTRANSMISSION AND DRIVETRAINTRANSMISSION CONTROL SYSTEMSDESCRIPTION AND OPERATIONFUNCTIONAL DESCRIPTIONSAFETY FUNCTIONS
1987 BMW L7 (E23) L6-3430cc 3.4L SOHC (M30)
Safety Functions
1987 BMW L7 (E23) L6-3430cc 3.4L SOHC (M30)SECTION Safety Functions
Safety Functions
Manually Engaged Downshifts
Manual downshifts are not carried out at excessively high speeds. At a vehicle speed above approx. 5 mph (8 km/h), the reverse lock prevents reverse gear being shifted hydraulically.
On-Board Diagnostics
By way of plausibility checks and checking the line connections for shorts or breaks, the control unit can detect and store defects.
Mechanical Emergency Program
In the event of failure of the transmission valve body control or when defects are detected which lead to critical driving situations (e.g.: impermissible downshifts), the mechanical emergency program is activated. Power supply to the solenoid valves in the transmission control unit is switched off (emergency program) and the failure display activated. The main pressure assumes its maximum value and the reverse lock and P/N shift-lock, if installed, of the selector lever are not active.
EGS Control System Failure
In the event of failure of the control unit, the power supply to the solenoid valves is cut (emergency program).
Engine Overrev Protection
To ensure the engine cannot be overrevved by downshifting during a control unit failure, the transmission shifts to 4th gear (emergency program) while driving. After restarting the engine, a hydraulic forced gearshift function ensures the vehicle drives in 3rd gear (emergency program).
Manually Engaged Downshifts
Manual downshifts are not carried out at excessively high speeds. At a vehicle speed above approx. 5 mph (8 km/h), the reverse lock prevents reverse gear being shifted hydraulically.
On-Board Diagnostics
By way of plausibility checks and checking the line connections for shorts or breaks, the control unit can detect and store defects.
Mechanical Emergency Program
In the event of failure of the transmission valve body control or when defects are detected which lead to critical driving situations (e.g.: impermissible downshifts), the mechanical emergency program is activated. Power supply to the solenoid valves in the transmission control unit is switched off (emergency program) and the failure display activated. The main pressure assumes its maximum value and the reverse lock and P/N shift-lock, if installed, of the selector lever are not active.
EGS Control System Failure
In the event of failure of the control unit, the power supply to the solenoid valves is cut (emergency program).
Engine Overrev Protection
To ensure the engine cannot be overrevved by downshifting during a control unit failure, the transmission shifts to 4th gear (emergency program) while driving. After restarting the engine, a hydraulic forced gearshift function ensures the vehicle drives in 3rd gear (emergency program).
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.