P1518 — Throttle Actuator Control (TAC) Module Serial Data Circuit

What Does P1518 Mean?

P1518 is a manufacturer-specific diagnostic trouble code: Throttle Actuator Control (TAC) Module Serial Data Circuit. This code applies to BUICK, CADILLAC, CHEVY, CHRYSLER, GM vehicles. Unlike generic OBD-II codes, manufacturer-specific codes are defined by the vehicle maker and may only apply to certain makes and models.

Symptoms of P1518

⚠️ Check Engine Light (MIL) illuminated
⚠️ Erratic Throttle Actuator Control (TAC) Module Serial Data readings
⚠️ Related system operating intermittently
⚠️ Reduced engine performance

Common Causes

🔍 Wiring issue in Throttle Actuator Control (TAC) Module Serial Data circuit (damaged, chafed, or corroded)
🔍 Faulty Throttle Actuator Control (TAC) Module Serial Data connector or terminal
🔍 Failed Throttle Actuator Control (TAC) Module Serial Data
🔍 ECM/PCM connection issue

Frequently Asked Questions

What does P1518 mean?

P1518 indicates: Throttle Actuator Control (TAC) Module Serial Data Circuit. The vehicle's computer has detected that the Throttle Actuator Control (TAC) Module Serial Data is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1518?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1518 for extended periods may cause additional problems.

How much does it cost to fix P1518?

Repair costs for P1518 typically range from $80 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 repair Throttle Actuator Control (TAC) Module Serial Data wiring and connectors
🔧 Replace faulty Throttle Actuator Control (TAC) Module Serial Data

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.

P1518: Throttle Actuator Control (TAC) Module Serial Data Circuit