Discovery 5 Stop/Start System Issues: Reprogramming and Root Cause Analysis
Many Land Rover Discovery 5 owners have voiced concerns regarding the functionality of the stop/start system. While designed to improve fuel efficiency and reduce emissions, this feature can sometimes become a source of frustration. One owner, experiencing persistent problems, has undertaken extensive data logging to understand the erratic behavior of their Discovery 5’s stop/start system and explore potential needs for Discovery 5 reprogramming of the Start/Stop system.
After seven attempts to rectify the issue, this owner’s experience goes beyond common gateway module problems or simple battery issues. Despite assurances of a healthy charging system and battery, the stop/start in their Discovery 5 operates with no discernible pattern. Over 15,000 kilometers, meticulous records were kept, documenting every parameter that could influence the system – from activated features and ambient temperature to the frequency and type of stop/start engagement. Even after disabling all non-essential features for 4,000 kilometers, the inconsistent operation persisted.
The core issue lies in the unpredictability. Regardless of adhering to handbook parameters or running a barebones system, the stop/start activation remains random. There are instances of prolonged stops at traffic lights, exceeding a minute, where the engine continues running, only for the stop/start to engage unexpectedly later. This lack of consistent behavior points towards a deeper underlying problem beyond simple sensor malfunctions.
Further investigation revealed anomalies extending beyond the stop/start system. Fuel efficiency figures displayed by the car’s computer are significantly higher than actual fuel consumption would suggest. Comparing current readings of 10L/100km in city driving with previous figures of 8.2-8.5L/100km for identical routes and driving conditions, a clear discrepancy emerges. This suggests a potential miscalculation or broader issue affecting the vehicle’s engine management system.
Adding to the complexity, cruise control performance is also erratic. While maintaining speed on flat and uphill roads, the system falters on slight downhill gradients. Instead of engine braking, the vehicle accelerates, with the computer intermittently applying brakes before seemingly giving up, leading to unintended speed increases.
Based on these detailed observations, the owner hypothesizes that the stop/start issue is not primarily battery-related, but rather stems from a malfunctioning computer system. This could manifest as incorrect signals to the drive-by-wire system or misinterpretation of sensor inputs. The upcoming meeting with the JLR dealer’s General Manager is crucial. Armed with extensive data, the owner intends to hand back the vehicle until a comprehensive solution is implemented, potentially involving system replacements and a complete computer re-flash. This experience underscores the frustrations some Discovery 5 owners face with unresolved technical issues and the pursuit of effective solutions like Discovery 5 Reprogramming The Start/Stop System to restore expected vehicle performance.
