C00A4 — Driveline Control Module Rear Differential Unit B Control Circuit Driver

What Does C00A4 Mean?

C00A4 is a diagnostic trouble code indicating: Driveline Control Module Rear Differential Unit B Control Circuit Driver. This code relates to the chassis system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of C00A4

⚠️ Check Engine Light (MIL) illuminated
⚠️ Erratic Driveline Control Module Rear Differential Unit B readings
⚠️ Related system operating intermittently
⚠️ ABS or stability control warning light

Common Causes

🔍 Wiring issue in Driveline Control Module Rear Differential Unit B circuit (damaged, chafed, or corroded)
🔍 Faulty Driveline Control Module Rear Differential Unit B connector or terminal
🔍 Failed Driveline Control Module Rear Differential Unit B
🔍 ECM/PCM connection issue

Frequently Asked Questions

What does C00A4 mean?

C00A4 indicates: Driveline Control Module Rear Differential Unit B Control Circuit Driver. The vehicle's computer has detected that the Driveline Control Module Rear Differential Unit B is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code C00A4?

Only short distances if absolutely necessary. C00A4 affects a critical system and should be diagnosed within a few days to avoid further damage.

How much does it cost to fix C00A4?

Repair costs for C00A4 typically range from $100 to $400, 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 repair Driveline Control Module Rear Differential Unit B wiring and connectors
🔧 Replace faulty Driveline Control Module Rear Differential Unit B

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

C00A4: Driveline Control Module Rear Differential Unit B Control Circuit Driver