P1783

What it means

On Nissan, P1783 means the transmission control unit has detected that the automatic transmission fluid has run too hot, or that the fluid temperature sensor signal is reading abnormally high. It is usually set after the fluid temperature stays above a calibrated limit for a set time, typically during heavy load, towing or sustained high-speed driving. The exact trigger point and the sensor location depend on the model and transmission type.

Symptoms

• Transmission warning light or overheat warning on the dash
• Reduced performance or sluggish acceleration as the transmission limits itself
• Harsh, delayed or flared gear changes
• Torque converter lock-up not engaging, with higher revs at cruising speed
• Burnt smell from the transmission fluid
• Transmission staying in a fixed gear (limp mode) in some cases

Possible causes

• Low, degraded or burnt transmission fluid, or the wrong fluid typelikely
• Sustained heavy load such as towing, mountain driving or stop-start use beyond normal operating conditionslikely
• Restricted or blocked transmission fluid cooler, cooler lines or radiator-side coolerpossible
• Faulty fluid temperature sensor or its circuit giving a false high reading, including damaged wiring or poor connector contactpossible
• Internal transmission wear causing slipping and excess heat, such as worn clutches or a failing torque converterpossible
• Engine cooling system fault raising radiator temperature and reducing cooler efficiencypossible
• Fault in the transmission control unit itselfrare

How to diagnose

1. Read all stored codes and freeze frame data, noting fluid temperature, vehicle speed and load at the time the code set
2. Ask about driving use, such as towing, heavy loads or prolonged stop-start driving, and any recent transmission work
3. Check the transmission fluid level and condition using the correct procedure for the model, looking for a burnt smell, dark colour or debris
4. Inspect the sensor wiring and connector for damage, corrosion, chafing or heat damage
5. Check the engine cooling system is working properly, including coolant level, fan operation and radiator condition
6. Inspect the transmission cooler and its lines for blockage, damage or kinks, and check flow where the procedure allows
7. Monitor live fluid temperature data on a test drive and compare it with the engine coolant temperature and the manufacturer's specified range
8. Check the sensor resistance or signal against the model-specific specification, and look for signs of internal slipping if the temperature really is high

How to fix

• Correct the fluid level and renew degraded fluid with the specified type, following the model-specific procedure
• Clear or replace a restricted transmission cooler or damaged cooler lines
• Repair or replace the faulty temperature sensor, or repair the damaged wiring or connector
• Repair any engine cooling system fault that is limiting cooling capacity
• Repair or overhaul the transmission if internal wear is causing the overheating
• Reduce the load or adjust driving use if the overheating is caused by operating conditions

Can I keep driving?

This code for other makes

• P1783FordTransmission Over-Temperature Condition
• P1783LincolnTransmission Over-Temperature Condition
• P1783MazdaTransmission Fluid Temperature High Input
• P1783MercuryTransmission Over-Temperature Condition
• P1783OtherTransmission Overtemperature Condition

Nearby codes

• P1781NissanTransmission 4x4 Low Switch Out Of Range Fault
• P1788NissanPressure Control Solenoid B Circuit Open