P0605: Internal Control Module Read Only Memory (ROM) Error
Can you still drive? Not recommended. ROM errors can cause the engine to run erratically or not at all. Have the vehicle towed to a qualified repair facility.
What Does P0605 Mean?
Code P0605 indicates that the PCM has detected an error in its Read Only Memory during a self-test. ROM contains the permanent programming that controls engine management strategies. A ROM error means the core operating instructions are corrupted or unreadable, which severely impacts engine control.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Internal PCM failure
- Corrupted firmware from failed update
- Electrical damage from voltage spike or reversed battery connection
- Water intrusion into PCM
- Age-related component degradation in PCM
Symptoms
- Check engine light on
- Engine may not start
- Severe driveability problems
- Engine running in limp or failsafe mode
- Multiple unrelated fault codes stored
Diagnostic Steps
- 1Verify battery voltage and charging system are stable
- 2Clear the code and recheck after ignition cycle
- 3Inspect PCM connectors and housing for moisture or corrosion
- 4Attempt to reflash PCM with manufacturer software
- 5If reflash fails or code returns, replace the PCM
- 6Check for TSBs related to PCM failures for your vehicle
Recommended Parts & Tools
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $300 - $1500 |
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Chat with AI About P0605Commonly Affected Vehicles
Related Recalls
5 Active Recalls — 2026 Ford Explorer
The following NHTSA safety recalls have been issued for this vehicle. Contact your dealer to check if your vehicle is affected.
VISIBILITY:WINDSHIELD
Ford Motor Company (Ford) is recalling certain 2025-2026 Lincoln Corsair, Lincoln Aviator, and Explorer vehicles. The windshield glass may have visible air bubbles, which can obscure the driver's visibility. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 205, "Glazing Materials."
Remedy: Dealers will inspect and replace the windshield as necessary, free of charge. Owner notification letters were mailed November 6, 2025. Owners may contact Ford customer service at 1-866-436-7332. Ford's number for this recall is 25C60. Vehicle Identification Numbers (VINs) involved in this recall become searchable on NHTSA.gov beginning October 27, 2025.
ENGINE
Ford Motor Company (Ford) is recalling certain 2026 Explorer, Mustang, Lincoln Corsair, and 2025 Maverick vehicles. The cylinder head may have been improperly manufactured, which can cause the ball plugs to fail, resulting in an oil leak.
Remedy: Dealers will replace the cylinder head assembly, free of charge. All affected vehicles are still within dealership inventory and therefore no owner notification letters will be mailed. Owners may contact Ford customer service at 1-866-436-7332. Ford's number for this recall is 25SD3. Vehicle Identification Numbers (VINs) involved in this recall became searchable on NHTSA.gov on November 24, 2025.
TRAILER HITCHES
Ford Motor Company (Ford) is recalling certain 2024-2026 Explorer and 2024-2026 Lincoln Aviator vehicles. The trailer hitch assembly bolts may be loose.
Remedy: Dealers will inspect and tighten the trailer hitch bolts, or replace them as necessary, free of charge. Owner notification letters were mailed October 29, 2025. Owners may contact Ford customer service at 1-866-436-7332. Ford's number for this recall is 25SA3. Vehicle Identification Numbers (VINs) involved in this recall became searchable on NHTSA.gov on October 15, 2025.
VISIBILITY:WINDSHIELD
Ford Motor Company (Ford) is recalling certain 2026 Explorer vehicles. During manufacturing, the windshield may not have been properly bonded to the vehicle, allowing it to detach in a crash. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 212, "Windshield Mounting."
Remedy: Dealers will remove and replace the windshield, free charge. Owner notification letters were mailed January 30, 2026. Owners may contact Ford customer service at 1-866-436-7332. Ford's number for this recall is 26C02. Vehicle Identification Numbers (VINs) involved in this recall became searchable on NHTSA.gov on January 22, 2026.
EXTERIOR LIGHTING:HEADLIGHTS
Ford Motor Company (Ford) is recalling certain 2025-2026 Explorer vehicles. The Dynamic Bending Light (DBL) system software may cause the passenger-side headlight to turn in the wrong direction when driving through curves in the road. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 108, " Lamps, Reflective Devices, and Associated Equipment."
Remedy: The headlight control module software will be updated by a dealer, or through an over-the-air (OTA) update, free of charge. Owner notification letters are expected to be mailed March 23, 2026. Owners may contact Ford customer service at 1-866-436-7332. Ford's number for this recall is 26C12. Vehicle Identification Numbers (VINs) involved in this recall became searchable on NHTSA.gov on March 5, 2026.
Data provided by the National Highway Traffic Safety Administration (NHTSA).
Frequently Asked Questions
What is ROM in the PCM?
ROM (Read Only Memory) contains the permanent software instructions the PCM uses to manage the engine. It includes fuel maps, timing tables, and control logic.
Can a PCM be repaired or does it need to be replaced?
Some specialists can repair PCM circuit boards, but replacement with a new or remanufactured unit is more common and reliable. The replacement PCM must be programmed to match your vehicle.
Community Fix Reports
Community reports are user-submitted and not verified by Auto AI Buddy. Results may vary.
Related Codes
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