Robert Shervill of RMS Diagnostics recently resolved a complex “no-start, no-lock” condition on a Range Rover that had previously stumped a specialist locksmith. The vehicle, brought in by the Salvage Rebuilds UK YouTube channel, suffered from an intermittent fault where the remote keys only functioned when held against the emergency start pad.
Although a specialist had already attempted to clone the Keyless Vehicle Module (KVM) and replace the aerials, the owner was still forced to manually lock the car with the emergency blade. Rob began his diagnostic process with a Thinkcar 399 scan, which surprisingly returned no relevant fault codes from the KVM or immobiliser modules
Recognising that the hardware had been ruled out, he moved past the screen to test the power supply and grounding of the remote receiver system.
While a standard multimeter showed a healthy 12V, Rob used a Load Pro tool to reveal a significant voltage drop the moment a load was applied to the circuit.
This led him to the fuse box, where he discovered a “fatigued” 5-amp fuse with a hairline crack that allowed voltage to pass but failed to carry the necessary current.
Replacing the fuse restored full functionality to both keys, proving that practical guidance and skill growth are more valuable than unnecessary component replacement.
Rob also cleared a communication error with the active grill shutters by cleaning tarnished connector pins, concluding a masterclass in how modern workshops can stay ahead and stay profitable.
Why watch
This video perfectly illustrates why relying on fault codes and static multimeter readings isn’t enough to stay competitive in a modern workshop. Robert Shervill’s systematic approach proves that simple, practical diagnostic techniques, like load testing a circuit, can solve nightmare jobs that have already stumped specialists and avoided expensive, unnecessary module replacements.
