1-2 shift solenoid problem in 99 Blazer?

Question

The check engine light came on for a 753 code which is the 1-2 shift solenoid. Is this a major problem that needs to be fixed right away? Any estimate on cost to fix this?

Answer 1

DTC P0753 is for the 1-2 shift solenoid circuit electrical.  This isn't a major problem but it might require removal of the transmission fluid pan for replacement of the trans wiring harness assembly or the 1-2 shift solenoid.  

The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The 1-2 SS valve is a normally-open exhaust valve that is used with the 2-3 SS valve in order to allow four different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 1-2 SS valve receives ignition voltage through circuit 1020. The powertrain control module (PCM) controls the solenoid by providing the ground path on circuit 1222.

When the PCM detects a continuous open or short to ground in the 1-2 SS valve circuit or the 1-2 SS valve, then DTC P0753 sets. DTC P0753 is a type A DTC.

You either have lost 12v+ feed to the shift solenoid, have an open or short in the control wire from the VCM to the 1-2 SS, a faulty 1-2 SS, a faulty A/T wiring harness assembly, or maybe even a faulty VCM.

It's not a huge problem, most likely just a wiring issue.  It shouldn't be that expensive to repair.  You'll likely pay more for labor time than any parts.