Suspension - Knocking Sound From Suspension

No: 60/01/00/NAS
Ref:
Issue: 1
Date: 04/21/00

ACE Self-Diagnostic Noise Reduction

AFFECTED VEHICLE RANGE:

Discovery Series II (LT) Up to VIN YA 233198
Vehicles with Active Cornering Enhancement (ACE) ONLY

SITUATION:

KNOCK FROM SUSPENSION ON SMOOTH ROADS

The customer may experience an occasional "knocking sound" under certain driving conditions:

^ When travelling at a speed above 15mph, (24km/h)

^ When travelling on a smooth surface with no camber

When the above conditions are maintained for longer than 7 seconds, the ACE system ECU may institute a self-diagnostic routine that closes hydraulic valves momentarily as an operational check. The driver may hear the valve actuation as a "knock".

RESOLUTION:

UPDATED ECU CALIBRATION

Where a customer complaint is confirmed, and the source of the symptoms verified, replace the ACE ECU with the new component detailed in PARTS INFORMATION.

PARTS INFORMATION:

RQT100024 ECU - ACE system

WARRANTY CLAIMS:

60.60.01 Time 1.20hrs.
Replace and calibrate the ACE ECU

FAULT CODE: Y

Normal warranty policy and procedures apply

REPAIR PROCEDURE

1. Verify the source of "knock" is the ACE valve block under the specified conditions.





2. Refer to Workshop Manual repair number 60.60.01 and replace the ACE ECU with the new component. (Figure 1)

3. When the ECU replacement is complete, connect TestBook to calibrate the ACE system.

4. On TestBook, go to the "Vehicle Maintenance - New ECU" Screen.

5. Follow the screen prompts to complete the calibration procedure.