What is P0781 fault code and what does it mean? What is the description for 1-2 Shift Malfunction How can you fix the P0781 fault? What are the causes and symptoms of the P0781 error code?
What is the P0781 fault code? What does it signify?
The 1-2 shift solenoid activates the hydraulic circuits to trigger the bands and clutches on vehicles equipped with an electronically controlled automatic transmission. The powertrain control and transmission module (TCM) control shift solenoids. If there is a problem with the 1-2 shift function or the PCM detects it, the code P0781 can be set.
Below is an image that shows how the shift solenoids are located in an automatic transmission.
What is the P0781 Fault Code?
The PCM detects a misalignment between the desired and detected gear ratios and lights the engine fault lamp. Sometimes, multiple faults can occur before the engine light turns on.
Here are some reasons why P0781 should be set.
- – Defective 1-2 shift solenoids
- – Clogged transmission fluid passagelines
- – Internal transmission problems
- – Transmission oil at a low level
- Filter and transmission oil that is not clean
- – Switch solenoid wiring harness can be opened or closed
- – A poor electrical connection in shift solenoid circuit
- Damaged cables or connectors
- – Defective transmission pump
- – Hydraulic control unit failure
- – Rarely, defective TCM or PCM
What are the symptoms of P0781 Malfunction Code?
These symptoms may be present in vehicles with code P0781.
- – Illumination at the check engine lights
- – Difficulty shifting gears
- – The vehicle won’t shift from 1st to 2nd gear
- Gearbox slipping
- Overheating the gearbox can lead to burning odors
- – An increase in fuel consumption
- – Irregularity with idle speed
- – Vehicle stalling when it is idle
- – Vehicle hesitation when acceleration is applied
- – Setting other fault codes in relation to shift solenoids
- – The vehicle enters failsafe mode, which allows one gear.
How to Fix the P0781 Fault Code
The following repairs may be able to resolve the P0781 fault code:
- – Replacing an faulty 1-2-shift solenoid
- Flushing transmission fluid lines
- – Fill the transmission fluid with more
- – Removing and replacing dirty transmission fluid.
- Repair of shorted or open cables
- – Reparing the bad electrical connection in the shift solenoid circuit
- – Replacing damaged cables or connectors
- – Replacing a defective transmission pump
- – Replacing an inoperable hydraulic control unit
- – Replacement of TCM or PCM in rare cases
Note: The P0782, P0784 and P0781 fault codes can be combined with the P0781 error code. These codes indicate that the transmission may be missing. Some mechanics direct blame the PCM/TCM, or shift solenoids when repairing this code. This problem is rarely caused by these parts. Sometimes, the problem is insufficient or dirty transmission fluid.
How serious is the P0781 Fault code?
You should immediately fix the problem if your vehicle displays a P0781 code. This code is a sign of a serious transmission problem. The vehicle may not be able to start if the problem is not fixed.
