U3503: Control Module Input Power A Circuit Intermittent/Erratic
Severity
Low
System
Vehicle Systems
What Does U3503 Mean?
U3503 is a diagnostic trouble code indicating: Control Module Input Power A Circuit Intermittent/Erratic. This code relates to the vehicle systems system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.
Symptoms of U3503
- ⚠️ Check Engine Light (MIL) illuminated
- ⚠️ Control Module Input Power A signal cutting in and out
- ⚠️ Related system working sometimes but not consistently
- ⚠️ System warning light illuminated
Common Causes
- 🔍 Loose or intermittent connection at Control Module Input Power A
- 🔍 Wire chafing causing intermittent contact
- 🔍 Control Module Input Power A failing under heat or vibration
- 🔍 Corroded connector pins with partial contact
Frequently Asked Questions
What does U3503 mean?
U3503 indicates: Control Module Input Power A Circuit Intermittent/Erratic. The vehicle's computer has detected that the Control Module Input Power A is not operating within its expected parameters and stored this diagnostic trouble code.
Can I drive with code U3503?
Yes, U3503 is generally safe to drive with in the short term. However, it should still be addressed to pass emissions testing and prevent potential secondary issues.
How much does it cost to fix U3503?
Repair costs for U3503 typically range from $30 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.
What To Do Next
Possible Fixes
- 🔧 Inspect and reseat all Control Module Input Power A connectors
- 🔧 Repair chafed or damaged wiring in Control Module Input Power A circuit
- 🔧 Replace Control Module Input Power A if failing intermittently
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.
Related Codes
U3500
Control Module Input Power A Circuit Range/Performance
U3501
Control Module Input Power A Circuit Low
U3502
Control Module Input Power A Circuit High
U3504
Control Module Input Power B Circuit Range/Performance
U3505
Control Module Input Power B Circuit Low
U3506
Control Module Input Power B Circuit High
U3507
Control Module Input Power B Circuit Intermittent/Erratic
U3508
Control Module Input Power C Circuit Range/Performance
U3509
Control Module Input Power C Circuit Low
U350A
Control Module Input Power C Circuit High