Car: Mercedes-Benz SLK (R170)
Status: Roof completely unresponsive / locked up after an interrupted opening cycle.
What Happened
Yesterday, I started opening the roof. The rear quarter windows rolled down and the sequence began normally (working smooth as butter), but I interrupted/stopped the opening process midway. After stopping it, the roof system completely stopped responding.
Current Symptoms
Switch Action: Pressing the roof switch causes a single relay click and a brief jerk/vibration from the rear assembly, but the main hydraulic pump does not continuously run or build pressure.
Red Light Status: The red light on the switch turns on/off depending on manual latching, but the sequence won't initiate automatically.
Windows: Main power windows function normally (limit stops have been reset).
Troubleshooting & Checks Completed
1. Hydraulic System:
Fluid level in the trunk reservoir is FULL and clean.
Opened the brass pressure relief valve on the pump by 0.5 to 1.5 turns to eliminate hydraulic pressure locking—the pump motor still only gives a single click/jerk without spinning up.
Retightened the relief valve back to its fully closed position afterwards.
2. Fuses (Checked in Engine Bay Fuse Box):
Fuse #24 (40A - Hydraulic Unit): Intact.
Fuses #19 & #20 (40A - Power Windows): Intact.
Fuse #7 (5A - Roof Switch Indicator): Intact.
3. Manual Reset & Mechanical Setup:
Manually unlatched and latched the front roof mechanism above the rear-view mirror using the 5mm Allen key.
Manually cycled/re-seated the roof panels and trunk frame back to their fully closed home positions.
Verified the luggage blind/partition in the trunk is firmly hooked into place on both sides to engage the safety switch.
Closed and firmly pressed down the trunk lid on both rear sides.
Current Question
Since the hydraulic fluid is full, fuses are intact, and relieving pressure manually didn't allow the pump motor to continuously spin, it seems like the N52 ECU is either blocking operation due to a microswitch position mismatch (e.g., front unlatch switch, tubular frame switch, or package tray sensor) or a stored "Sequence Timeout" fault code.
Has anyone experienced this exact single-click/pump-jerk issue following an interrupted roof cycle? Which microswitch is most likely out of sync in this state, or is a 38-pin STAR/XENTRY diagnostic reset required to clear the ECU lockout?
Status: Roof completely unresponsive / locked up after an interrupted opening cycle.
What Happened
Yesterday, I started opening the roof. The rear quarter windows rolled down and the sequence began normally (working smooth as butter), but I interrupted/stopped the opening process midway. After stopping it, the roof system completely stopped responding.
Current Symptoms
Switch Action: Pressing the roof switch causes a single relay click and a brief jerk/vibration from the rear assembly, but the main hydraulic pump does not continuously run or build pressure.
Red Light Status: The red light on the switch turns on/off depending on manual latching, but the sequence won't initiate automatically.
Windows: Main power windows function normally (limit stops have been reset).
Troubleshooting & Checks Completed
1. Hydraulic System:
Fluid level in the trunk reservoir is FULL and clean.
Opened the brass pressure relief valve on the pump by 0.5 to 1.5 turns to eliminate hydraulic pressure locking—the pump motor still only gives a single click/jerk without spinning up.
Retightened the relief valve back to its fully closed position afterwards.
2. Fuses (Checked in Engine Bay Fuse Box):
Fuse #24 (40A - Hydraulic Unit): Intact.
Fuses #19 & #20 (40A - Power Windows): Intact.
Fuse #7 (5A - Roof Switch Indicator): Intact.
3. Manual Reset & Mechanical Setup:
Manually unlatched and latched the front roof mechanism above the rear-view mirror using the 5mm Allen key.
Manually cycled/re-seated the roof panels and trunk frame back to their fully closed home positions.
Verified the luggage blind/partition in the trunk is firmly hooked into place on both sides to engage the safety switch.
Closed and firmly pressed down the trunk lid on both rear sides.
Current Question
Since the hydraulic fluid is full, fuses are intact, and relieving pressure manually didn't allow the pump motor to continuously spin, it seems like the N52 ECU is either blocking operation due to a microswitch position mismatch (e.g., front unlatch switch, tubular frame switch, or package tray sensor) or a stored "Sequence Timeout" fault code.
Has anyone experienced this exact single-click/pump-jerk issue following an interrupted roof cycle? Which microswitch is most likely out of sync in this state, or is a 38-pin STAR/XENTRY diagnostic reset required to clear the ECU lockout?
