P0828: Up and Down Shift Switch Circuit High

Many selectors read tap-up and tap-down over one shared wire with voltage steps or a resistor network; P0826–P0828 cover this shared circuit, P0815/P0816 the single directions. P0828 means the shared circuit voltage is too high – a short to positive, or on ground-switching switches with a pull-up also an open. No manufacturer document available to us uses it: Saab's 9-3 Sentronic reports this state as P0826 (above 6.7 V for more than 30 s), Saab's 9-4X as P0815 or P0816, and GM as P0826. Manual shifting would be disabled while automatic operation stays normal.

Medium severity. Can I keep driving?Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.

Symptoms

Tap or manual shifting not working
Transmission warning in the cluster
No effect on driving in automatic mode

Most likely causes

Signal wire shorted to positive
Signal wire or selector ground open (pulled-up input)
Selector assembly faulty
Control module

What to check, in order

Start with the simplest. You can tick off each step.

Check the fluid level and condition according to the manufacturer
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Check the transmission connector
Read the data with a transmission-compatible scanner
Measure the solenoid valve circuit
Leave opening the transmission to a specialized repair shop

Good to know

Repair difficulty: medium

What each character of P0828 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
8: Transmission
28: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0828?

Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.

What causes code P0828?

The most common causes are: signal wire shorted to positive; signal wire or selector ground open (pulled-up input); selector assembly faulty.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.