P1871 — Transmission Mechanical Transfer Case 4x4 Switch Circuit Short To Battery

What Does P1871 Mean?

P1871 is a manufacturer-specific diagnostic trouble code: Transmission Mechanical Transfer Case 4x4 Switch Circuit Short To Battery. This code applies to OTHER, BUICK, CADILLAC, CHEVY, 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 P1871

⚠️ Check Engine Light (MIL) illuminated
⚠️ Transmission Mechanical Transfer Case 4x4 Switch not functioning as expected
⚠️ Related system may be in fail-safe mode
⚠️ Reduced engine performance

Common Causes

🔍 Faulty Transmission Mechanical Transfer Case 4x4 Switch
🔍 Wiring or connector issue in Transmission Mechanical Transfer Case 4x4 Switch circuit
🔍 Related mechanical or electrical fault
🔍 ECM/PCM issue (rare)

Frequently Asked Questions

What does P1871 mean?

P1871 indicates: Transmission Mechanical Transfer Case 4x4 Switch Circuit Short To Battery. The vehicle's computer has detected that the Transmission Mechanical Transfer Case 4x4 Switch is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1871?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1871 for extended periods may cause additional problems.

How much does it cost to fix P1871?

Repair costs for P1871 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 Mechanical Transfer Case 4x4 Switch and related wiring
🔧 Replace faulty Transmission Mechanical Transfer Case 4x4 Switch

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.

P1871: Transmission Mechanical Transfer Case 4x4 Switch Circuit Short To Battery