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Home >> GMC >> 1998 >> Yukon RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 70 (Automatic Transmission Diagnosis - 4L80-E (Gasoline)) >> Diagnostic Tests >> DTC P0751: 1-2 Shift Solenoid ("A") Performance Malfunction >> Circuit Description

Circuit Description

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The 1-2 shift solenoid (solenoid "A") is used to control fluid flow acting on 1-2 and 3-4 shift valves. Solenoid is a normally open exhaust valve that is used in conjunction with 2-3 shift solenoid (solenoid "B"), to allow 4 different shifting combinations. Solenoid is attached to control valve body. Ignition voltage is supplied directly to solenoid through fused circuit. VCM commands solenoid on or off through ground circuit. DTC P0751 will set if VCM detects incorrect gear ratios or shift pattern, depending on mechanical failure.