P1745: Transmission Control Unit Relay Short To B+

VOLKSWAGEN OTHER FORD LINCOLN MERCURY MAZDA JAGUAR

Severity

Medium

System

Manufacturer-Specific Powertrain

Last reviewed: Jan 1, 0001 Last updated: Jan 1, 0001

Methodology: We combine code standards with complaint and reliability patterns, then review for clear, vehicle-first diagnosis steps.

Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).

Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.

What Does P1745 Mean?

P1745 is a manufacturer-specific diagnostic trouble code: Transmission Control Unit Relay Short To B+. This code applies to VOLKSWAGEN, OTHER, FORD, LINCOLN, MERCURY 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 P1745

⚠️ Check Engine Light (MIL) illuminated
⚠️ Transmission Control Unit Relay Short To B+ not functioning as expected
⚠️ Related system may be in fail-safe mode
⚠️ Reduced engine performance

Common Causes

🔍 Faulty Transmission Control Unit Relay Short To B+
🔍 Wiring or connector issue in Transmission Control Unit Relay Short To B+ circuit
🔍 Related mechanical or electrical fault
🔍 ECM/PCM issue (rare)

Frequently Asked Questions

What does P1745 mean?

P1745 indicates: Transmission Control Unit Relay Short To B+. The vehicle's computer has detected that the Transmission Control Unit Relay Short To B+ is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1745?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1745 for extended periods may cause additional problems.

How much does it cost to fix P1745?

Repair costs for P1745 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 Transmission Control Unit Relay Short To B+ and related wiring
🔧 Replace faulty Transmission Control Unit Relay Short To 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.