Powertrain, generic · Transmission

P0826 Up and Down Shift Switch Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

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. P0826 is the general fault of the shared circuit. GM (6L80 in 2011, 2019, 2025, hybrids) sets it when the circuit shows an invalid voltage for at least 60 s with 8.6–32 V and 400–7500 rpm, without MIL. On Saab's 9-4X with the 6T70 a short to ground or an open sets P0826. Saab's 2003–04 9-3 Sentronic reports below 0.2 V or above 6.7 V for over 30 s under P0826 with a fault-type byte, lights 'Check gearbox' and locks the lever in P/N. Ram's 2025 heavy-duty trucks set it with P0827 and P085F and the MIL, fixed with transmission software. Manual shifting is then disabled.

Likely causes

Wire or connector between selector and module open or shorted
Selector assembly (Hall switch, resistor network, module) faulty
Transmission module software (Ram)
Clockspring or steering wheel wiring (paddles)

Symptoms

  • Tap or manual shifting not working
  • Transmission runs only in automatic mode
  • Transmission warning; lever locked in P/N (Saab 9-3)

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–600
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

tap shift switchgear selectorswitch wiringtransmission control module

Related codes

P0827P0828P0815P0816P0819

References: gsi.ext.gm.com, gsi.ext.gm.com, saabwisonline.com, saabwisonline.com.