P0603: Internal Control Module Keep Alive Memory (KAM) Error
Can you still drive? Yes, this is safe to drive. The engine may run slightly rough until it relearns its adaptive values, which usually takes a few drive cycles.
What Does P0603 Mean?
Code P0603 indicates that the PCM has lost its Keep Alive Memory data, which stores long-term adaptive values such as fuel trim corrections and idle speed adjustments. KAM is maintained by constant battery power, so this code often appears after a battery disconnect, replacement, or a power supply interruption to the PCM.
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
- Recent battery disconnect or replacement
- Blown fuse supplying constant power to PCM
- Corroded battery cable or terminal
- Parasitic drain causing battery to go dead
- Faulty PCM power relay
Symptoms
- Check engine light on
- Rough idle after battery service
- Temporary poor fuel economy
- Engine hesitation until adaptive values relearn
Diagnostic Steps
- 1Check if the battery was recently disconnected or replaced
- 2Verify constant battery power supply to the PCM with a multimeter
- 3Check PCM power supply fuses
- 4Inspect battery terminals and cables for corrosion or looseness
- 5Clear the code and drive to allow adaptive values to relearn
- 6If code returns without battery service, check PCM power circuits
Recommended Parts & Tools
battery terminal cleaner
OBD-II scanner
automotive fuse kit
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $0 - $300 |
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Chat with AI About P0603Commonly Affected Vehicles
Related Recalls
1 Active Recall — 2026 Ford F-150
The following NHTSA safety recalls have been issued for this vehicle. Contact your dealer to check if your vehicle is affected.
ELECTRICAL SYSTEM: INTEGRATED TRAILER BRAKE CONTROL
Ford Motor Company (Ford) is recalling certain 2021-2026 F-150, 2022-2026 F-250 SD, F-350 SD, F-450 SD, F-550 SD, Maverick, 2024-2026 Ranger, 2023-2026 F-600 SD, 2022-2027 Lincoln Navigator, Expedition, and 2026 E-Transit vehicles. When towing a trailer, the integrated trailer module (ITRM) may lose communication with the vehicle, possibly causing a loss of brake and turn signal lights, or a loss of brake function. 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 integrated trailer 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 17, 2026. Owners may contact Ford customer service at 1-866-436-7332. Ford's number for this recall is 26C10. Vehicle Identification Numbers (VINs) involved in this recall will be searchable on NHTSA.gov beginning March 17, 2026.
Data provided by the National Highway Traffic Safety Administration (NHTSA).
Frequently Asked Questions
Is P0603 normal after replacing a battery?
Yes, P0603 commonly appears after a battery replacement because the KAM data is lost when power is interrupted. Clear the code and drive normally for a few days.
Will P0603 go away on its own?
It may not clear itself automatically. Use an OBD-II scanner to clear the code after verifying the battery connections are clean and tight. If it returns, investigate further.
Community Fix Reports
Community reports are user-submitted and not verified by Auto AI Buddy. Results may vary.
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