P071B: Transmission Mode Switch A Circuit Low
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 P071B Mean?
P071B is a diagnostic trouble code indicating: Transmission Mode Switch A Circuit Low. This code relates to the transmission system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.
Symptoms of P071B
- ⚠️ Check Engine Light (MIL) illuminated
- ⚠️ Transmission Mode Switch A reading at zero or minimum value
- ⚠️ Related system not functioning or in fail-safe mode
- ⚠️ Harsh or delayed shifting
Common Causes
- 🔍 Open or broken wire in Transmission Mode Switch A circuit
- 🔍 Poor ground connection at Transmission Mode Switch A
- 🔍 Faulty Transmission Mode Switch A with no output signal
- 🔍 Disconnected or loose Transmission Mode Switch A connector
- 🔍 Blown fuse in related circuit
Frequently Asked Questions
What does P071B mean?
Can I drive with code P071B?
How much does it cost to fix P071B?
What To Do Next
Possible Fixes
- 🔧 Repair broken wire or restore ground in Transmission Mode Switch A circuit
- 🔧 Clean and secure Transmission Mode Switch A connector and ground points
- 🔧 Replace failed Transmission Mode Switch A
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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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Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.