Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DBβ LIVE
HOMESERVICE MANUALSCHEVROLET2009AVALANCHE 6.0 Y, RWDREPAIR AND DIAGNOSISTRANSMISSIONAUTOMATIC TRANSAUTOMATIC TRANSMISSION - 6L80/6L90 - INTRODUCTIONSPECIFICATIONSTRANSMISSION INTERNAL MODE SWITCH LOGIC
2009 Chevrolet Avalanche 6.0 Y, RWD
Transmission Internal Mode Switch Logic
2009 Chevrolet Avalanche 6.0 Y, RWDSECTION Transmission Internal Mode Switch Logic
| Gear Selector Position | Signal A | Signal B | Signal C | Signal P |
|---|---|---|---|---|
| Park | LOW | HI | HI | LOW |
| Park/Reverse | LOW | LOW | HI | LOW |
| Reverse | LOW | LOW | HI | HI |
| Reverse/Neutral | HI | LOW | HI | HI |
| Neutral | HI | LOW | HI | LOW |
| Neutral/Drive 6 | HI | LOW | LOW | LOW |
| Drive 6 | HI | LOW | LOW | HI |
| Drive 6/Drive 4 | LOW | LOW | LOW | HI |
| Drive 4 | LOW | LOW | LOW | LOW |
| Drive 4/Drive 3 | LOW | HI | LOW | LOW |
| Drive 3 | LOW | HI | LOW | HI |
| Drive 3/Drive 2 | HI | HI | LOW | HI |
| Drive 2 | HI | HI | LOW | LOW |
| Open | HI | HI | HI | HI |
| Invalid | HI | HI | HI | LOW |
| Invalid | LOW | HI | HI | HI |
| HI = Ignition voltage LOW = 0 volts |
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RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.