Advice on RR Sport Malfunctions

[Mututing]

I own a 2018 RR Sport HDV 6 HSE (225KW) that I have owned from its factory release.

Five weeks ago, I saw that after halting at a crossroads or traffic signal, the engine refused to restart when releasing the brake and would just switch off. I have to reset the start button to activate it. It occurred sporadically, and in two instances, it failed to initiate despite pressing the start button, only commencing after many tries. I scheduled the diagnostics for the following day; however, the vehicle stuck at a congested intersection that same day and would not restart. It was necessary to tow it to the dealership. There were no issues in the dashboard code.

The technician identified a throttle body issue based on an error code I did not see while the vehicle was in my possession. Although I was doubtful of this diagnosis, believing it to be an auxiliary battery problem impacting the auto shut-down and restart functionality, I ultimately spent $3,000 to have it fixed.

After two weeks, the vehicle began to exhibit the same issue as before. Upon application of the brakes, the engine will shut down automatically as anticipated; nevertheless, it fails to restart when the brakes are released. This occurrence was becoming more regular, prompting me to return the vehicle to the dealership. They have recommended acquiring a new starter motor, relay, and doing retesting. I am really dubious about this diagnosis. They are once again billing me over $3,000 for this matter.

I am aware that a non-dealer technician may replace the starter motor at a lower cost; yet, I remain unconvinced that this is the true issue.

Do you have any ideas or suggestions?

[PopeyeR]

Primarily, the "dashboard error codes" are not shown on the dashboard. The Check Engine Light may or may not illuminate; the ECU records several problem codes, however not all trigger the CEL. The mechanic used a diagnostic computer to get the codes from the ECU records.

Secondly, you have been requested to remit $3,000, and your vehicle has undergone certain component replacements. Seemingly without success. The first favourable outcome, in my opinion, is attributable to a complete system reset rather than the component replacements. I would consent to pay an additional $3,000 only if I were refunded my prior $3,000, since my intention was to rectify a problem rather than to replace unrelated components. Clearly, do this action upon retrieving the vehicle rather than before to its relinquishment.

A malfunctioning starter motor might also exhibit failures under various conditions, particularly when attempting to hot-start the vehicle after a brief parking interval. The circumstances are almost identical to auto start-stop, but with some exceptions, such as the drive selection remaining in drive rather than park. If you do not get this with hot restarts, I doubt it is a starting motor problem.

Ultimately, without a corresponding set of codes pertaining to the issue, we can only engage in speculation until someone has had the same problem. The standard procedure involves resetting the error codes, operating the vehicle until a fault transpires, and thereafter retrieving the error codes, which will provide a more in-depth analysis of the problem. I suspect a communication issue between the engine and gearbox ECU.

[Mututing]

That is beneficial; thank you!

The dealership is denying reimbursement of $3,000 for the prior repair, claiming that they resolved the fault identified during diagnostics at that time.

I have obtained quotations from independent technicians for the starter motor, which are clearly less than half the prices indicated by the dealer.

I have rejected the dealer's diagnosis and requested a second assessment, which I must get independently. I will retrieve my automobile later.

[PopeyeR]

If your independent mechanic has a JLR-compatible code reader (a generic code reader retrieves just normal OBD2 codes, but a JLR-compatible reader also offers a compilation of proprietary JLR codes that extend beyond the basic OBD2 standard), instruct him to read and analyse the codes. Their association with mileage allows for a clear identification of the cutoff after "fixed by dealer." Publish all of them subsequent to the resolution of the matter.

[Mututing]

I retrieved my automobile from the dealership and disabled the auto stop-start feature, subsequently driving for an hour in congested urban and freeway traffic. The vehicle did not experience a single stall. I now have a strong suspicion about a problem with the auxiliary battery that operates the stop-start feature. Enquiring if this feature may be permanently deactivated. This deactivating option is only accessible on new Defender models, as discovered on YouTube.

[PopeyeR]

An adept ECU tuner (remapper) may invert the operation of the button.

[PopeyeR]

 

[PopeyeR]

I assume the L461 has a fairly similar configuration. I would stabilise the plug using foam secured by a rubber rope and attach it to prevent resonance.

[Mututing]

That is impressive. I will complete it tomorrow throughout the day.

[PopeyeR]

What was the outcome?

[Mututing]

Regrettably, the vehicle has halted once again. The battery jumpstart was ineffective. It fails to initiate regardless of the circumstances. The incident occurred when the auto start-stop feature was engaged.

Strangely, the automobile started operation the next morning. However, I had over my limit by that time, so I arranged for it to be hauled to another dealership.

[Mututing]

A such incident occurred before as well. It became inoperative, and the recovery technician was unable to restart it. The vehicle was transported to the prior dealership, where it started upon inspection. They were unable to ascertain the defect since they did not do a test drive and concluded that a throttle body replacement was necessary based on diagnostics. This did not resolve the issue, and the same problem recurred.

Uncertain if the second dealership can provide an appropriate diagnostic. I have informed them of all the predictions about several possibilities, including issues with the auxiliary battery, starting motor, and battery alternator.

Only God comprehends the issue at hand.

[PopeyeR]

Grounding strap? Or a malfunctioning starting motor, perhaps?

[Mututing]

Group strap? The starter motor may be defective.