Test 06 - Control Unit, Front Wheel Simulation

1987 BMW L7 (E23) L6-3430cc 3.4L SOHC (M30)SECTION Test 06 - Control Unit, Front Wheel Simulation




TEST SEQUENCE
1. Connections needed:
- T-plug (4a) with adapter (A) at Antilock Brake System (ABS) wire harness (1)
- T-plug (4b) and adapter (B) at ABS control unit (2)
- Connecting lead from adapter (A) and (B) to cigar lighter - red telltale lamp must come "On"
- Switch position at adapter (A) on '7' model and test step 06 (left), at adapter (B) on '7' model and 5 A - compare with nominal pressure drop values
2. Switch "On" ignition; note voltage between leads 1 and 10.
3. When pressure buildup values appear, press acknowledge key.
4. When pressure drop values appear, press acknowledge key. Compare with nominal values.
5. Repeat test step with switch position 2 A (adapter "B"), compare with nominal pressure retention values.





Nominal Values

6. Compare the displayed actual values obtained from the test equipment with the nominal values provided above. If nominal values are not obtained, proceed with the troubleshooting procedures below as needed.

TROUBLESHOOTING
Voltage Between Wires 1 And 10
- Turn "On" ignition.
- Run engine.

Battery charged (check).

Solenoid Valve
Left Pressure Buildup, Drop, Hold

- Due to high switching "On" power, possibly repeat test step with engine running.

Replace control unit and repeat test step.

- If in test steps 08, 09 and 10 valves do not "Switch" or pump does not "Run":

Replace hydraulic unit.

Right Pressure Buildup, Drop, Hold
- Due to high switching "On" power, possibly repeat test step with engine running.

Replace control unit and repeat test step.

- If in test steps 06, 09 and 10 valves do not "Switch" or pump does not "Run":

Replace hydraulic unit.



RENDER: 1.0x

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:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.