Porsche Cruise Control Module

Porsche Cruise Control Module Post-Repair Troubleshooting Guide

Important: Use this guide if you reinstalled your repaired Porsche Cruise Control Module and the problem is still happening.

Important: Please do not open/disassemble the module. This can damage the unit and may void warranty coverage.

Step 1: Confirm the install is 100% solid

• Key OFF
• Unplug the module connector(s), then plug back in until they fully seat/lock
• Inspect for bent pins, pushed-out terminals, corrosion, or moisture
• Make sure the harness isn’t stretched/pulled tight

Step 2: Verify brake lights (cruise won’t work if this input is wrong)

• Turn key ON
• Press/release brake pedal multiple times
• Confirm brake lights come ON every time and turn OFF every time
• If brake lights are stuck ON/OFF or intermittent, fix that first (cruise will not engage)

Step 3: Check fuses related to cruise/brake/ignition

• Use a test light or meter (don’t rely on visual checks)
• Check all “Stop/Brake Lamp,” “Cruise,” and “Ignition” fuses
• If a fuse is blown and blows again, stop and inspect wiring for a short

Step 4: Confirm cruise switch/stalk is working

• Test ON/OFF, SET/COAST, RESUME/ACCEL
• If the switch is intermittent, inspect steering column connectors and wiring
• If equipped with a clutch switch (manual), confirm it’s adjusted/working (a bad clutch switch will block cruise)

Step 5: Confirm the speed signal is present

• Road test (safe area)
• Verify the speedometer works normally and does not drop out
• If the speedometer is erratic/intermittent, cruise usually won’t set—focus on the vehicle speed sensor/sender and wiring

Step 6: Vacuum checks (if your system is vacuum-actuated)

• Inspect vacuum hoses for cracks/loose fittings
• Check the one-way check valve and vacuum reservoir (if equipped)
• If there is a vacuum leak or hissing, cruise may not hold speed

Step 7: Throttle linkage/actuator check

• Confirm throttle linkage/cable moves freely and returns smoothly
• Look for binding linkage, missing clips, or an out-of-adjustment cable

Step 8: If this started after recent work

• Re-check anything recently touched: brake switch, clutch switch, fuse panel, steering column connectors, vacuum lines, grounds
• Look for a connector left slightly unplugged or a pinched wire

Step 9: What to send UpFix if it still won’t work

• VIN
• Year/model
• Do brake lights work correctly? (Yes/No)
• Does the speedometer ever drop out? (Yes/No)
• What happens when you press ON and then SET? (Nothing / light changes / sets then cancels)