The internal mode switch, sometimes referred to as the park/neutral switch or transmission range selector, is responsible for telling that TCM which gear has been selected. If an issue has been detected, a P1819 diagnostic trouble code will be stored.
How Serious is the Code?
A P1819 diagnostic trouble code is fairly serious because the TCM can command the highest line pressure, which can damage the clutches and other important components.
Symptoms of a P1819 include:
- Harsh shifting
- Failed gear engagement
- PRNDL display stops working
- Limited torque converter operation
- Limp mode
- Faulty internal mode switch
- Shift cable damage to or out of adjustment
How to Diagnose the Code?
In order to diagnose a P1819 diagnostic trouble code, the shift cable and the internal mode switch will have to be checked for proper adjustments. If everything checks out, internal mode switch has failed.
What Repairs Will Fix P1819?
Adjusting the shift cable
Replacing the internal mode switch
P1820 – Internal Mode Switch Circuit A Low
P1821 – Internal Mode Switch Circuit B Low
P1822 – Internal Mode Switch Circuit B High
P1823 – Internal Mode Switch Circuit P Low
P1824 – Internal Mode Switch Circuit P High
P1825 – Internal Mode Switch Invalid Range
P1826 – Internal Mode Switch Circuit C High