← View Generic P0603 Guide
Severity: Medium
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Vehicle-Specific Guide
This guide is customized for your 2021 Honda PASSPORT
P0603: Internal Control Module Keep Alive Memory Error
on 2021 Honda PASSPORT
Fix Cost
$200 - $1500
Parts & Labor
Difficulty
5/5
2-4 hours
DIY Possible?
❌ No
Pro recommended
Your Vehicle
2021 Honda
PASSPORT
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Important for 2021 Honda PASSPORT Owners
Before starting repairs, verify which engine your 2021 Honda PASSPORT has. Check your VIN or engine code to ensure you order the correct parts.
📖 What Does P0603 Mean on 2021 Honda PASSPORT?
The engine control module has lost its keep alive memory, which stores learned parameters and adaptations.
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Symptoms
- • Check engine light
- • poor performance
- • rough idle
- • transmission shifting problems
- • loss of learned parameters.
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Common Causes
- • Weak battery
- • power supply interruption to ECM
- • faulty ECM
- • poor battery connections
- • alternator problems.
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How to Fix P0603 on 2021 Honda PASSPORT
Test battery and charging system, check ECM power and ground circuits, replace battery if weak, reprogram ECM.
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Need Maintenance Info for Your PASSPORT?
Get oil capacity, filter specs, and torque settings for your specific 2021 Honda PASSPORT.
View 2021 Honda PASSPORT SpecsParts for 2021 Honda PASSPORT
Essential Tool
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Related Diagnostic Codes
Other codes that may appear with P0603
P0601
Sequential Code
Internal Control Module Memory Check Sum Error
High
P0602
Sequential Code
Control Module Programming Error
High
P0604
Sequential Code
Internal Control Module Random Access Memory Error
High
P0605
Sequential Code
P0605: Engine Control Module (ECM) Output Circuit Malfunction
High
💡 Why These Codes Are Related:
- • Similar Issues: Same root cause or component failure
- • Related Problems: Often occur together due to system interactions
- • Sequential Codes: Progressive failure stages or multiple sensors
- • Same System: Components within the same automotive system