P0758 -What Does It Mean? (1999-2006 V8 Chevrolet Silverado, GMC Sierra)

A trouble code P0758: 2-3 Shift Solenoid Circuit Electrical Malfunction usually tells you that the transmission isn't shifting correctly because the 2-3 shift solenoid has failed.

In this tutorial, I'll explain what this trouble code means. I'll also talk about some of the tests you can perform to find its cause.

NOTE: The 2-3 shift solenoid is also known as shift solenoid B.

You can find this tutorial in Spanish here: Código P0758 ¿Qué Significa? (1999-2006 V8 Chevrolet Silverado, GMC Sierra) (at: autotecnico-online.com).

APPLIES TO: This tutorial, on the P0758 OBD II trouble code, applies to the following vehicles:

Chevrolet:

• 4.8L Chevrolet Silverado (1500, 2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• 5.3L Chevrolet Silverado (1500, 2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• 6.0L Chevrolet Silverado (2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006

GMC:

• 4.8L GMC Sierra (1500, 2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• 5.3L GMC Sierra (1500, 2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• 6.0L GMC Sierra (2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006

RELATED TROUBLE CODES:

• P0753 -What Does It Mean? (1999-2006 V8 Chevrolet Silverado, GMC Sierra).

What Does Trouble Code P0758 Mean?

A trouble code P0758: 2-3 Shift Solenoid Circuit Electrical Malfunction lets you know that the 2-3 shift solenoid (located on the automatic transmission's valve body) is not functioning properly.

To be a bit more specific, it tells you that the fuel injection computer has commanded the 2-3 shift solenoid ON and that:

• The specified rpm change that happens when the transmission shifts from 2nd gear to 3rd gear DID NOT occur.
• The vehicle speed sensor (VSS) did not report an increase in road speed.

Common Symptoms Of A P0758 Trouble Code

Depending on the severity of the problem, you'll see one or more of the following symptoms:

• Check engine will be illuminated.
• Transmission functions in "limp-in" mode only (which means that the fuel injection computer commands the transmission to stay in 3rd gear only).
• No 1st or 2nd gear.

NOTE: A bad 2-3 shift solenoid will not cause the transmission to slip. If your pickup's automatic transmission is 'slipping', then this points to an internal mechanical failure and not an electrical/electronic one.

What Does The 2-3 Shift Solenoid Do?

The 4L60-E (4L65-E, 4L80-E, 4L85-E) automatic transmission in your Chevrolet Silverado (GMC Sierra) is an electronically controlled transmission.

It uses electronic shift solenoids to control transmission upshifts and downshifts (in addition to the input of several other transmission sensors and switches).

Two of these shift solenoids are the:

• 1-2 shift solenoid (or shift solenoid A)
• 2-3 shift solenoid (or shift solenoid B)

To achieve the different transmission gears, the shift solenoids are commanded ON or OFF by the fuel injection computer.

What Causes A P0758 Trouble Code?

In the majority of cases, a bad 2-3 shift solenoid is the cause of the P0758 trouble code lighting up the check engine light on your Chevrolet Silverado (GMC Sierra).

Other things that can cause a P0758 trouble code are:

• Damaged or loose solenoid connector.
• Internal automatic transmission mechanical problem.

How To Diagnose And Repair A P0758 Trouble Code

Troubleshooting and solving a trouble code P0758 usually involves replacing the 2-3 shift solenoid.

Before buying and replacing the shift solenoid, I recommend that you test it to make sure its bad.

Testing the 2-3 shift solenoid simply involves:

• Testing the solenoid's internal resistance (specification: 19-31 Ohms).
• Checking its electrical connector for damage.

If you do replace the 2-3 shift solenoid, it's recommended to replace the 1-2 shift solenoid as well.

The following tutorial explains how to test the 2-3 shift solenoid on the 4L60-E automatic transmission (the procedure is similar for the 4L80-E automatic transmission):

• How To Test Shift Solenoids A And B (1999-2010 V8 Chevrolet Silverado, GMC Sierra).

Where To Buy The 2-3 Shift Solenoid And Save

Since you'll need to remove the transmission fluid pan to replace the shift solenoid, I recommend that you avoid buying cheap brand-X knock-off shift solenoids.

I recommend that you buy the original factory AC-Delco (or Delphi) solenoid and make it a repair that won't come back in a few weeks.

The following links will help you comparison shop for the AC-Delco and Delphi shift solenoids:

NOTE: The AC-Delco brand is the original equipment part for the Chevrolet Silverado and GMC Sierra.

More Chevrolet Silverado (GMC Sierra) Tutorials

You can find a complete list of V8 Chevrolet Silverado (GMC Sierra) tutorials in this index:

• GM 4.8L, 5.3L, 6.0L Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• Resistance Specifications Of The TAC Electronic Throttle Body.
• How To Test The GM Accelerator Pedal Position (APP) Sensor 2.
• How To Test The MAF Sensor (GM 4.8L, 5.3L, 6.0L, 8.1L).
• Blown Head Gasket Test (GM 4.8L, 5.3L, 6.0L).