Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / P0605 — Internal Control Module Read Only Memory (ROM) Error

P0605 — Internal Control Module Read Only Memory (ROM) Error

Detailed page for trouble code P0605.

35,336codes
59brands
11,925generic
23,411specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

P0605

MERCEDES-BENZ P — Powertrain

Internal Control Module Read Only Memory (ROM) Error

Brand: MERCEDES-BENZ
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Corrupted or failed ROM/firmware inside the control module
  • Interrupted or failed software update/programming
  • Low or unstable battery voltage during programming or normal operation
  • Poor power/ground connections to the module
  • Water intrusion, corrosion, physical damage to module PCB or connectors
  • Intermittent wiring short or open on power, ground, or communication bus

Symptoms

  • Malfunction Indicator Lamp (MIL) illuminated or lamp on with other DTCs present
  • One or more modules failing to communicate on CAN (no comm) or showing intermittent comm
  • Vehicle may enter limp/home mode or experience degraded performance
  • Failure to start or intermittent starting problems in some cases
  • Loss of features controlled by the affected module (e.g., engine, transmission, ABS, instrumentation)
  • Faults reappear after clearing or after driving

What to check

  • Scan vehicle with a capable OEM-capable diagnostic tool; record freeze frame and all stored/related DTCs
  • Check vehicle battery state of charge and system voltage (engine off and cranking voltage)
  • Inspect module power and ground circuits for proper voltage, continuity and secure connections
  • Inspect module connectors and wiring for corrosion, water intrusion, bent pins, or damage
  • Verify whether a recent software update or reflash was attempted; check for interrupted programming events
  • Check for communication errors on CAN bus and related modules reporting faults (use oscilloscope or diagnostic tool bus data if available)

Signal parameters

  • Battery voltage (key ON, engine OFF; during cranking)
  • Module supply voltage and ground continuity (Vbatt at module pin)
  • CAN/LIN bus activity and error counters (bus voltage, dominant/recessive levels)
  • Module “alive”/heartbeat status as shown by OEM scan tool
  • Memory checksum or software version/calibration identifier reported by scan tool
  • DTC set count and freeze frame parameters

Diagnostic algorithm

  1. Connect an OEM-capable scan tool and read all stored and pending DTCs; note related/communication codes and freeze frame data.
  2. Verify battery health and ensure battery is fully charged (preferably >12.4 V); check charging system. Charge or replace battery if low.
  3. Inspect module connectors and wiring: disconnect battery before disconnecting connectors where required by procedure; look for corrosion, water ingress, bent pins, or damage.
  4. Check power and ground circuits at the module: measure Vbatt at the module power pin with ignition ON and check ground resistance to chassis. Repair any wiring faults.
  5. Check vehicle communication network (CAN): verify other modules respond, view CAN traffic with OEM tool or scope to confirm healthy bus. Repair bus issues first.
  6. If wiring/power/communications are good, try reading module info (software/calibration numbers). If ROM/software appears corrupted or blank, follow OEM reprogramming procedure.
  7. Attempt a controlled reflash/reprogram of the module using factory diagnostic software and the correct calibration file; ensure stable power (battery charger/maintainer) during reflash and follow key/immobilizer precautions.
  8. If reprogramming fails repeatedly or the module reports hardware ROM failure, replace the control module with a correct OEM unit. Ensure correct VIN/coding is applied and reprogram modules as required (backup/transfer immobilizer data and keys if applicable).
  9. After repair or reflash, clear DTCs and road test to confirm the fault does not return; re-scan to confirm no related communication faults remain.

Likely causes

  • Failed or corrupted module firmware/ROM
  • Recent failed or incomplete reflash/update
  • Bad power supply (low battery, poor charging, loose battery terminal) during a programming event
  • Damaged connectors/corrosion at module pins or shorted wiring harness
  • Defective control module hardware

Fault status

⚠️ Status
P0605 - Internal Control Module ROM Error: module memory failed read/verification. Reprogramming may recover the module; module replacement could be required if hardware ROM is faulty.
🔴 Repair difficulty: Hard
⏱️ Diagnostic time: 2-6 hours

Similar codes

P0600 P0601 P0606 P0607 U0100 U0073
856

Browse 856 MERCEDES-BENZ manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MERCEDES-BENZ

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .