Unfortunately, the McLaren Senna has run into another problem. The hypercar has been recalled in the United States, over a part of the engine wiring harness bundle brushing against a “link pipe heatshield”. The recall report published by the NHTSA explains that the issue could potentially cause engine stall, engine misfire, or even rupturing of the exhaust system.
A total of 129 units manufactured between 15 June 2018 to 26 June 2019 are suspected to have the aforementioned issue. However, the report says that all Senna vehicles sold in the United States prior to 8 August 2019 are included in the recall population.
A branch of the vehicle engine harness can potentially come into contact with a metal link pipe heatshield. If there is contact, there may over time be chafing of the engine harness. If this chafing breaches the harness heatshield wrap and the harness outer sleeve, this could lead to damage to the wires contained within the engine harness bundle. McLaren’s sample testing (of 61 vehicles) showed that 15% of vehicles had marking on the outer cover of the engine harness as a result of chafing.
Potential consequences are: the car entering idle limp mode (significant engine power reduction), torque limitation (slight engine power reduction), engine stall, engine misfire, and unburnt fuel in the catalyst that could lead to increased temperature of the catalyst. In the event of unburnt fuel in the catalyst, if the driver does not turn the engine off, unburnt fuel would continue to enter the catalyst, resulting in overheating of the catalyst. If the catalyst overheats, rupture to the exhaust system cannot be ruled out. This would lead to hot gas escaping into the engine bay. Full report here.
However, the driver will receive a warning prior to any of the potential safety risks occurring. The type of warning will vary depending on the nature of the consequence. The driver will receive a dashboard warning light, a dashboard warning message and an audio alert signal, the report added.
Discovery
A customer vehicle was inspected on 1st August 2019, revealing that damage could occur as a result of the engine harness bundle touching a link pipe heatshield. The customer vehicle showed evidence of chafing of the outer sleeve of the engine harness bundle.
The report further adds that on 2nd August 2019, McLaren launched a full investigation to assess whether the issue was isolated, and to identify possible consequences of chafing to the engine harness bundle. During a follow-up meeting on 5th August 2019 to review initial findings, it was confirmed that the issue was not isolated, and that the engine harness bundle was proximate to or touching a link pipe heatshield in other vehicles in production.
The remedy, apparently, is a simple and quick procedure that can be carried out in the field by McLaren’s authorized dealers and technicians. This rework will be carried out free of cost.
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