P0605

Code

LAND ROVER P — Powertrain

Internal control module ROM test error

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 23 EN: 37 RU: 43

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Page language: EN

Causes

Corrupted or incomplete module software/firmware (failed reflash/programming)
Failed or degraded ROM/flash memory inside the control module
Low or unstable battery voltage during programming or operation
Intermittent power/ground or connector/circuit corrosion to the module
Water ingress or physical damage to the module
Manufacturing defect or age-related internal component failure

Symptoms

Malfunction Indicator Lamp (MIL/CEL) illuminated
Possible engine limp mode or reduced performance
No-start or unpredictable engine behavior in severe cases
Loss of one or more functions controlled by the affected module
Communication errors with the PCM seen on a scan tool
Other stored module-related or network DTCs present

What to check

Read all stored and pending DTCs from all modules; record freeze frame and history
Check battery state-of-charge and battery/cable condition; verify stable voltage (12.4–12.8 V nominal when off, >12 V with key On, >13.5 V running)
Inspect power and ground circuits at the PCM: connectors, pins, corrosion, and secure mounting
Inspect PCM for water intrusion, physical damage or burn marks
Scan module programming/part number and software/calibration ID for known updates
Check CAN/bus communication quality and presence of other module communication faults

Signal parameters

PCM not responding on diagnostic bus or intermittent response
Module software part number/calibration ID available via dealer scanner (may be blank or fail CRC check)
Internal ROM checksum/CRC mismatch reported by advanced diagnostic tool
Battery voltage and cranking voltages during tests (expected ranges)
Bus voltage on CAN/communication lines (nominal ~2.5 V idle differential)

Diagnostic algorithm

Connect a capable scan tool and record all DTCs and freeze frame data from the PCM and related modules.
Verify battery voltage and charging system. Charge or replace battery if low; ensure stable power during testing and reprogramming.
Visually inspect PCM connectors and wiring for damage, corrosion, bent pins, or water contamination. Repair any issues and reseat connectors.
Check power and ground circuits at the PCM with a digital meter; confirm proper voltage on supply pins and low resistance to ground on ground pins.
Verify CAN/bus communications: check for shorted/open bus, correct termination, and presence of other communication DTCs. Repair bus faults first.
If hardware and bus are good, attempt to read module software/calibration IDs. If the module reports a corrupted or missing calibration, attempt a reprogram/reflash with the correct OEM software and stable power source following Land Rover procedure.
If reflash fails or programming cannot be completed, retest charging and wiring and repeat reflash attempt. Follow dealer guidelines (use dealer-level tool and correct vehicle-specific files).
If reprogramming cannot restore a valid ROM or if module continues to fail self-tests, consider module replacement with proper programming and VIN coding. Retest system and clear codes.
After repair or reflash, road test and rescan for recurrence. If fault returns, escalate to manufacturer technical support for module-level diagnosis or warranty replacement.

Likely causes

Previous unsuccessful software update or interrupted programming
Battery discharged or jump-start occurred during recent module programming
Damaged module connector or corroded pins causing intermittent communication
Module exposed to moisture leading to internal memory corruption
Known software fault for the specific Land Rover module calibration requiring dealer reflash

Fault status

⚠️ Status

Internal Control Module ROM Test Error — module internal memory/firmware integrity check failed. May require reprogramming or module replacement.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours

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P0605 — Internal control module ROM test error