Convertibles, or ‘Out Tops’ as my grandmother would call them, are chic and stylish, exuding glamour and perfect for country drives on glorious sunny days. But what do you do when the convertible roof gets ‘out of sync’? Here at A1 Diagnostics we recently had a case of just that. Pictured below is a BMW Z4 experiencing roof sync issues.
A convertible roof is described as ‘out of sync’ when the control button only seems to action the windows dropping, and doesn’t cause the roof to start folding unless there is manual assistance. There are several causes of this, from switch alignment through to sensor alignment or low pressure in the hydraulics.
BMW Z4s have a ‘Convertible Top Module’ which interprets signals from microswitches to confirm when the roof is locked or unlocked. If this switch doesn’t register properly then the Module thinks there’s a problem and halts movement of the roof. A warning light will flash, too, so the driver is aware that there is a potential problem.
On a more mechanical level, regular operation of the folding roof can cause damage to the wiring harness that runs across the roof and side hinges. Repeatedly opening and closing can damage the wires sitting within the structure of the roof itself. Damage of this nature can cause occasional signal loss to the sensors and microswitches.
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The final cause of out of sync convertible roofs is a drop in hydraulic pressure. Sometimes pumps can lose pressure, or their release valves weren’t fully reengaged. In both these scenarios, the hydraulic pump wouldn’t have enough oomph to draw the roof up to its final position. Latching the roof into place can then be a significant problem.
Happily for our BMW owner, none of these causes are difficult to fix. Diagnostics services, like those run by A1 Diagnostics, can identify issues with the Convertible Top Module and quickly identify whether a microswitch is to blame for the issue. The wiring within the roof itself can be inspected visually and any broken or fraying wires can again be replaced.
The Hydraulic Release Handle which operates the all-important pump can be pushed back into its normal resting place, restoring full power to the hydraulic pump. And the Beemer’s microswitches can be tested by a combination of manual operation and online checks where data from the switches is analysed to see if they are fully operational if moved manually.
All of these techniques can be employed when diagnosing the root causes of an ‘out of sync’ roof. If you’ve got issues with the function of your convertible’s folding roof, get in touch with our team at A1 Diagnostics who will be able to help!
