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Code P1900

Symptoms

• Overheating transmission

• Transmission slipping

• Warning light on dashboard

Common Causes

• Blocked transmission fluid cooler

• Faulty transmission fluid pump

• Clogged transmission fluid lines

Glossary

Transmission Fluid Cooler: A component that helps keep the transmission fluid at the correct temperature.

Transmission Control Module (TCM): An electronic device that controls transmission functions.

Related Codes

• P1901

• P1902

Official description

Transmission Fluid Cooler No Flow Detected

Laymans terms

The car's system is saying that the part that cools the transmission fluid isn't working because no fluid is moving through it.

Explanation

This code indicates that the vehicle's computer has detected no flow of transmission fluid through the cooler, which can lead to overheating and transmission damage.

Technical description

The transmission fluid cooler is responsible for maintaining the temperature of the transmission fluid by dissipating heat. If the flow is obstructed or absent, the transmission can overheat, leading to potential failure. The code P1900 is triggered when the transmission control module (TCM) or powertrain control module (PCM) detects a lack of fluid flow in the cooler.

Diagnosis steps

• Check transmission fluid level and condition

• Inspect transmission fluid cooler for blockages

• Test transmission fluid pump functionality

Repair procedures

• Clear any blockages in the cooler

• Replace faulty transmission fluid pump

• Flush and replace transmission fluid

Tools required

• OBD-II scanner

• Transmission fluid pressure gauge

• Basic hand tools

Estimated repair cost

$150 - $500

Difficulty level

Moderate

Commonly affected vehicles

• Ford F-150

• Chevrolet Silverado

• Dodge Ram

Preventive measures

• Regular transmission fluid checks

• Routine maintenance of cooler

• Avoid overloading vehicle

Error code type

Transmission Performance

User experience recommendations

• Avoid driving until the issue is resolved to prevent damage

• Consult a professional mechanic for a thorough inspection

Warranty information

Check with your vehicle manufacturer for specific warranty coverage related to transmission components.

Historical data

This code has been associated with vehicles that have high mileage or those that frequently tow heavy loads.

Urgency level

High – Address immediately to prevent transmission damage.

Legal and safety notice

Ignoring this issue can lead to severe transmission damage and potential safety hazards while driving.

Testing conditions

• Engine running

• Transmission at operating temperature

Component location

The transmission fluid cooler is typically located at the front of the vehicle, near the radiator.

FAQs

Q: Can I drive with a P1900 code?
A: It's not recommended to drive with this code active, as it can lead to transmission overheating and damage.

Q: How do I know if my transmission fluid cooler is blocked?
A: Signs of a blocked cooler include transmission overheating, slipping, and unusual noises.

Last updated: Apr 16, 2026 • Source: internal database
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