Problem Code P0826 OBD-II: Up and Down Switch Input Circuit

Diagnostic code P0826 OBDII is a sign that the powertrain control (PCM) transmission module has detected that a problem is occurring in the electrical circuit of the up/down shift lever that works in conjunction with the transmission range correlation circuit.

This circuit includes the wiring, switch, connectors and actuators so that they are used in vehicles that join an automatic transmission with manual transmission. When this system is activated correctly, the upshift or downshift initiates, and the appropriate signals are received in the transmission control module.

However, when a variation in the up/down shift switch circuit voltage is detected that does not match the variations described in the manufacturer's specifications, a problem code P0826 OBDII is generated, which causes the corresponding light to come on the vehicle dashboard.

Signs of an occurring P0826 OBDII problem

• The engine light (Check Engine) on the dashboard comes on
• Sudden transmission changes
• Transmission enters emergency mode
• Unavailability of torque converter bypass function

Causes

• Short circuit in the wiring of the system
• Locked or damaged gear lever
• Transmission mode switch defects
• Liquids spilled on the shift switch

How to fix it

If you notice any of the above signs, it is important that you take your vehicle with the mechanic to check the electrical wiring and switch connections for damage such as wear, corrosion, burns, open circuits or short circuits. In case the components are damaged they must be replaced.

It is also important to check that all cables in the system have ground reference voltage signals and, if there is any fault, make the necessary adjustments.

However, it is important to note that the engine control light does not always come on at all although the other signs may occur, in which case the vehicle must be checked to perform the repairs described. In addition, sometimes, when a problem code P0826 is stored, the overdrive light also flashes.

In addition to visual inspection of all wiring, the mechanic can use a scanner, a digital voltmeter, and the vehicle manufacturer's wiring diagram to have the diagnosis and make the connections correctly.

Ignoring the dashboard alert and not repairing the problems associated with code P0826 can be so serious that it is could be impossible to drive the vehicle.

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