Land Rover · Range Rover Sport P400e · L494 · 2019
Range Rover Sport P400e: NOT READY state and interrupted charging
The vehicle refused to enter the READY state, the electric drive was disabled and charging stopped immediately. The authorised workshop said the only option was a new battery pack for over CZK 650,000 — or leaving the car parked in the garden.
- PHEV
- Li-Ion 13,1 kWh
- Duration
- 18 days
System status
Before the intervention
NOT READY · HV system disabled
After the final check
READY · all circuits nominal
Battery pack architecture
13.1 kWh Li-Ion pack
- Isolation resistance
- 0,18 MΩcritical leakage> 500 MΩnominal
- Voltage delta
- 380 mVout of tolerance< 15 mVwithin tolerance
- Load test
- —not possible48 hno deviations
Schematic view of the modules and the control unit. Not a manufacturer drawing.
Fault codes stored in memory
- P0AA1High-voltage contactor and precharge circuit — the HV bus does not close and the vehicle stays NOT READY.
- P292DMismatch between commanded and actual high-voltage contactor state.
- P0AA6Low high-voltage isolation resistance — the system blocks charging and driving for safety reasons.
- P0B24Battery voltage sense deviation — the difference between pack segments exceeded the allowed limit.
- U0111Lost communication with the battery control module (BECM) during the high-voltage bus collapse.
For the vehicle owner
The owner of a 2019 Range Rover Sport L494 P400e left the car parked overnight. In the morning the dashboard stayed on NOT READY after pressing Start, together with a Hybrid System Fault warning. The electric drive was fully disabled and charging stopped the moment the cable was connected. The authorised workshop read high-voltage faults. The manufacturer's official procedure knows no repair for this case — the battery is treated as a single indivisible unit, so the only proposed solution was ordering a complete new pack for more than CZK 650,000. The out-of-warranty owner was essentially told to either pay a sum close to the residual value of the car, or leave it standing at home as an immobile monument. R/EVIVE took the case over, assessed the available evidence and coordinated the specialist intervention.
- Vehicle will not charge
- Hybrid System Fault / Hybrid Battery Fault warning
- Vehicle is immobile
- Quote to replace the complete battery pack
Result and final check
The vehicle now switches to READY immediately after pressing Start. Electric drive and range are fully restored, charging from a regular socket and from a wallbox runs without interruption and the fault memory is clear. The final measurement confirmed isolation resistance above 500 MΩ and a voltage delta below 15 mV. The owner received the measurement report and a 1-year warranty with unlimited mileage from R/EVIVE / EvoGrowth s.r.o. The car returned to service without investing in a new battery pack costing over CZK 650,000.
R/EVIVE's role
R/EVIVE coordinated the case, communication and continuity of steps. The technical work was carried out by the relevant specialist facilities.
Technical detail
Diagnostic finding
The initial review and measurements confirmed this was neither a software anomaly nor a fault outside the battery system. The 12V network, charging, wiring and control software versions were all in order. The high-voltage bus never closed for safety reasons: the electronics detected a critical drop in isolation resistance together with an out-of-limit voltage deviation between pack segments. The bus collapse also took down communication with the battery control module. Measurements showed an isolation resistance of 0.18 MΩ (critical leakage) and a voltage delta of 380 mV between segments — both far outside tolerance.
Confirmed cause
The confirmed cause was a localised fault inside one segment of the battery pack, which caused both the loss of isolation and the voltage deviation. The remaining modules and the battery control module showed healthy values with no signs of degradation. The pack as a whole was not at the end of its life. The stored fault codes described a consequence, not a need to replace the entire unit.
Work carried out
01 · Initial verification and exclusion of external causes — checking the 12V network, signal paths and software versions to rule out false faults before any removal. 02 · Coordination and safe removal — collecting the vehicle and removing the battery at a cooperating specialist workshop under high-voltage safety procedures. 03 · Specialist intervention — transporting the pack alone to a specialist facility, examining the internal modules, restoring nominal isolation resistance and levelling the voltages of the individual blocks. 04 · Load test — 48 hours of cycling and a capacity test under full simulated load before closing the battery enclosure. 05 · Refitting and commissioning — installing the pack back into the vehicle at the partner workshop, initialising the battery control module and test running in both electric and hybrid mode. 06 · Handover — final measurement report and return of the vehicle to the owner.
A fault code alone does not identify a specific failed component. Symptom, diagnostic finding and confirmed cause are three different things.
Author: Johnathan J. Pácha. Technical review: Patrik Tatar.
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