Powertrain
generic / SAE
P2779
Downshift Switch Circuit Range/Performance
The downshift switch signal is implausible. Stuck or noisy contacts. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number7 / 79
Possible causes
- Contamination on switch contacts medium
- Worn switch contacts medium
- Sensor element aged beyond calibration window low
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 80–600 €
- Estimated time: 0.5–2.5 h
- Component: downshift switch
- Component: steering wheel controls
- MIL / check engine light
Sources
References
sae:J2012