If your vehicle has a P1812 DTC, then one of two things has happened. 1. The transmission fluid has exceeded the acceptable temperature limit and is now in an overheat condition. 2. A sensor or other problem has caused this diagnostic trouble code to be stored.
How Serious is the Code?
A P1812 diagnostic trouble code is extremely serious, because serious internal damage can occur if the transmission is overheated. And if another problem is causing this DTC, then it means that the transmission fluid temperature is not being correctly monitored.
Symptoms of a P1812 include:
- Check engine light / check transmission light illuminated
- Smoke coming from the transmission
- Transmission fluid has overheated
- Faulty transmission fluid temperature sensor / TFT sensor
How to Diagnose the Code?
In order to diagnose a P1812 diagnostic trouble code, the transmission will have to be examined for signs of an overheat event. If transmission overheating has occurred, then further diagnosis will be needed to determine the cause. If no evidence of transmission overheating is found, then the transmission fluid temperature sensor / TFT sensor circuit will have to be examined for possible problems.
What Repairs Will Fix P1812?
A number of things could cause the transmission to overheat, including clogged hydraulic passages, torque converter problems, and short circuits. If the transmission did not overheat, then repairing or replacing the TFT sensor may be necessary.
P0710 – Transmission Fluid Temperature Sensor Circuit.
P0711 – Transmission Fluid Temperature Sensor A Circuit Range/Performance
P0712 – Transmission Fluid Temperature Sensor A Circuit Low Input
P0713 – Transmission Fluid Temperature Sensor A Circuit High Input
P0714 – Transmission Fluid Temperature Sensor A Circuit Intermittent