Iveco 34 – ECAS (Electronically Controlled Air Suspension) Control Unit: Malfunction of the right third-axis electrovalve / lift (Short circuit to + DC)

The electrical circuit controlling the right-side solenoid valve for the third (lift) axle has shorted to positive battery voltage, preventing the valve from operating correctly to route air into or out of the air springs.

• Iveco Stralis
• Iveco Trakker
• Iveco Eurotronic

1. 1

   Inspect the wiring harness running from the ECAS ECU to the right third-axis solenoid valve for chafed insulation, melted wires, or pinches that could cause a short to positive DC power.

2. 2

   Disconnect the bayonet-style electrical connector (DIN 72585) at the solenoid valve and check for water ingress, corrosion, or bent pins that could bridge the connections.

3. 3

   Use a multimeter to test the internal resistance of the right third-axis solenoid coil (24V) to check for an internal short.

4. 4

   Check the ECAS system fuses and relays to ensure the baseline power supply to the valve block is stable and correct.

1. 1

   Preparation

   Safely chock the wheels and support the vehicle chassis.

2. 2

   Depressurize

   Completely depressurize the air suspension system to prevent injury when removing pneumatic components.

3. 3

   Disconnect Power

   Disconnect the vehicle's batteries to prevent further electrical shorts.

4. 4

   Locate the Valve

   Locate the ECAS solenoid valve block mounted on the chassis near the rear/third axle.

5. 5

   Disconnect Lines

   Disconnect the electrical connectors from the solenoids. Mark and disconnect the pneumatic air lines (typically M22x1.5 VOSS fittings) from the valve block.

6. 6

   Remove Valve Block

   Unbolt the mounting hardware and remove the faulty ECAS valve block from the chassis.

7. 7

   Overhaul (Optional)

   If using a repair kit instead of replacing the entire block, remove the valve end caps, extract the faulty solenoids, springs, and valve plates, and install the new components with fresh O-rings.

8. 8

   Installation

   Mount the new or repaired ECAS solenoid valve block back onto the chassis.

9. 9

   Reconnection

   Reconnect all M22x1.5 VOSS air lines and the DIN electrical connectors.

10. 10

    Testing

    Reconnect the batteries, start the truck, and allow the air compressor to build system pressure. Clear the fault codes from the ECAS ECU and perform a suspension leveling test to ensure the third axle lifts and lowers properly.