John Deere 1058.18 – BCU: Information for Operator: Pressure Switch for Air-Brake System Is Not Activated (Pressure Too Low)

Triggered when the control unit detects that the pressure switch for the air brake system has not been activated because the pneumatic pressure in the system has fallen below the required operational threshold.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6230
• 6330
• 6430
• 7430
• 7530
• 5080R
• 5090R
• 5100R
• 5080RN
• 5090RN
• 5100RN
• 6M-1654
• 6M-1854
• 6M-2104
• 6165J
• 6185J
• 6205J
• 6210J

1. 1

   Verify Actual System Pressure: Connect a mechanical air pressure gauge to the air brake system test port to determine if the pressure is genuinely low or if the sensor is providing a false reading.

2. 2

   Inspect for Air Leaks: Check the air compressor, reservoir tanks, air lines, and valve blocks for audible or visible air leaks.

3. 3

   Check Compressor Output: Ensure the engine-driven air compressor is functioning properly and building pressure within the specified time frame.

4. 4

   Inspect the Switch and Wiring: Locate the air brake pressure switch. Inspect the electrical connector and wiring harness for damage, corrosion, or loose pins.

5. 5

   Test the Pressure Switch: Using a multimeter, test the pressure switch for continuity. It should change states (open/closed) when the system reaches the specified pressure threshold.

6. 6

   Test the Harness: If the switch tests good, check the wiring harness between the pressure switch and the BCU for opens, shorts to ground, or high resistance.

1. 1

   Safely park the tractor on level ground, engage the parking brake, and turn off the engine. Chock the wheels.

2. 2

   If an air leak or compressor fault is found: Repair the mechanical source of the low pressure

   (e.g., replace leaking air lines, fittings, or service the air compressor).

3. 3

   If the pressure switch is faulty: Bleed all residual air pressure from the air brake system to prevent injury.

4. 4

   Disconnect the electrical connector from the faulty air brake pressure switch.

5. 5

   Unthread the switch from the air brake manifold or valve block.

6. 6

   Install the new air brake pressure switch.

   Ensure any required thread sealant or O-ring is in place, and tighten to the manufacturer's torque specification.

7. 7

   Reconnect the electrical harness to the switch.

8. 8

   Start the tractor and allow the air compressor to build system pressure.

9. 9

   Verify that the BCU 001058.18 fault code clears from the display and that the air brakes operate correctly.