P1909 — Trans Temp Sensor Circuit Open or Shorted to Pwr or Gnd

What Does P1909 Mean?

P1909 is a manufacturer-specific diagnostic trouble code: Trans Temp Sensor Circuit Open or Shorted to Pwr or Gnd. This code applies to OTHER 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 P1909

⚠️ Check Engine Light (MIL) illuminated
⚠️ No signal from Trans Temp Sensor
⚠️ Related system defaulting to backup values
⚠️ Reduced engine performance

Common Causes

🔍 Broken wire in Trans Temp Sensor circuit
🔍 Disconnected Trans Temp Sensor electrical connector
🔍 Trans Temp Sensor internal open circuit failure
🔍 Corroded terminal pins preventing electrical contact

Frequently Asked Questions

What does P1909 mean?

P1909 indicates: Trans Temp Sensor Circuit Open or Shorted to Pwr or Gnd. The vehicle's computer has detected that the Trans Temp Sensor is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1909?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1909 for extended periods may cause additional problems.

How much does it cost to fix P1909?

Repair costs for P1909 typically range from $30 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

🔧 Locate and repair broken wire in Trans Temp Sensor circuit
🔧 Replace damaged Trans Temp Sensor connector
🔧 Replace Trans Temp Sensor if internally open

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.

P1909: Trans Temp Sensor Circuit Open or Shorted to Pwr or Gnd