Truck won’t upshift from 1 to 2 without taking my foot off of the gas then it shifts normally, up and down. Kicks into passing ok. Don’t think there is a vacuum modular on this model.
This is an electronic solenoid valve body. The VSS – Vehicle Speed Sensor and Throttle signals are used to determine shift points. There may be an issue with the shift valve also. You should check to see if any codes are stored and post the codes if any are present.
Possible code set: P0751
Chevy Code P0751: 1-2 Shift Solenoid Valve Performance
Code P0751 Description
The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The solenoid is a normally-open exhaust valve. With the 2-3 SS valve, the 1-2 SS valve allows four different shifting combinations.
When the VCM detects a 1-1-4-4 or a 2-2-3-3 shift pattern, depending on the state of the mechanical failure, then DTC(Diagnostic Trouble Code) P0751 sets. DTC P0751 is a type A DTC.
Conditions for Running the DTC
- No TP sensor DTC P0122 or P0123
- No VSS assembly DTC P0502 or P0503
- No TCC solenoid valve DTC P0740
- No TCC stuck ON DTC P0742
- No 1-2 Shift Solenoid Valve DTC P0753
- No 2-3 SS valve DTC P0758
- No 3-2 SS valve assembly DTC P0785
- No TFP manual valve position switch DTC P1810
- No TCC PWM solenoid valve DTC P1860
- The gear range is D4
- The vehicle speed is greater than 5 mph
- The TP angle is 10-35%
- The TP angle is constant within +/- 7%
- The VCM commands a 1-2, 2-3 and 3-4 shift
- The TCC is commanded ON
- The engine speed is greater than 450 RPM for 5 seconds
- The transmission fluid temperature is 68-266F Degrees
- The engine is not in fuel cutoff
Code P0751 Testing
