P1780: Transmission Control Switch Circuit, Overdrive Off Switch Not Cycled During The Self Test
MAZDA
MERCEDES
NISSAN
CADILLAC
CHEVY
GM
GMC
BUICK
Severity
Medium
System
Manufacturer-Specific Powertrain
What Does P1780 Mean?
P1780 is a manufacturer-specific diagnostic trouble code: Transmission Control Switch Circuit, Overdrive Off Switch Not Cycled During The Self Test. This code applies to MAZDA, MERCEDES, NISSAN, CADILLAC, CHEVY 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 P1780
- β οΈ Check Engine Light (MIL) illuminated
- β οΈ Erratic Transmission Control Switch readings
- β οΈ Related system operating intermittently
- β οΈ Reduced engine performance
Common Causes
- π Wiring issue in Transmission Control Switch circuit (damaged, chafed, or corroded)
- π Faulty Transmission Control Switch connector or terminal
- π Failed Transmission Control Switch
- π ECM/PCM connection issue
Frequently Asked Questions
What does P1780 mean?
P1780 indicates: Transmission Control Switch Circuit, Overdrive Off Switch Not Cycled During The Self Test. The vehicle's computer has detected that the Transmission Control Switch is not operating within its expected parameters and stored this diagnostic trouble code.
Can I drive with code P1780?
You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1780 for extended periods may cause additional problems.
How much does it cost to fix P1780?
Repair costs for P1780 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 ($80β$150 at most shops) will identify the exact cause before committing to expensive parts.
What To Do Next
Possible Fixes
- π§ Inspect and repair Transmission Control Switch wiring and connectors
- π§ Replace faulty Transmission Control Switch
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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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3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50β$150) pinpoints the root cause.
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