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

Testing shift solenoid A and shift solenoid B, in your 1999-2008 V8 equipped Chevrolet Silverado and GMC Sierra is not hard.

In this tutorial, I'll explain how to resistance test them with a multimeter. You'll be able to easily find out if they're bad or not.

NOTE: Shift solenoid A refers to 1-2 shift solenoid. Shift solenoid B refers to the 2-3 shift solenoid.

You can find this tutorial in Spanish here: Cómo Probar Los Solenoides De Cambio A y B (1999-2010 V8 Chevrolet Silverado, GMC Sierra) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

Chevrolet (4L60E, 4L65E, 4L70E automatic transmissions):

• 4.8L Chevrolet Silverado (1500, 2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
• 5.3L Chevrolet Silverado (1500, 2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
• 6.0L Chevrolet Silverado (2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

GMC (4L60E, 4L65E, 4L70E automatic transmissions):

• 4.8L GMC Sierra (1500, 2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
• 5.3L GMC Sierra (1500, 2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
• 6.0L GMC Sierra (2500): 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

RELATED TROUBLE CODES:

• P0753 -What Does It Mean? (1999-2006 V8 Chevrolet Silverado, GMC Sierra).
• P0758 -What Does It Mean? (1999-2006 V8 Chevrolet Silverado, GMC Sierra).

Important Suggestions And Tips

TIP 1: To test shift solenoid A and B, you'll need to remove the transmission oil pan.

You'll need to take certain precautions before removing the transmission oil pan. Please read the section: Before You Remove The Transmission Oil Pan.

This section is a must read to avoid any complications you might have in finishing the job.

TIP 2: Before removing the transmission pan (to test the shift solenoids), let the engine cool down completely.

Transmission fluid gets hot and remains hot long after the vehicle has been turned off. Be careful, take all necessary safety precautions. Think safety all of the time.

TIP 3: A bad transmission shift solenoid A or B will not cause the transmission to slip.

So if your transmission is slipping, replacing the shift solenoids, even if they're fried will not solve the slipping issue.

Shift Solenoid A And B Basics

The 4L60-E transmissions uses several solenoids and sensors to control/activate its 4 gears. The two that we're concerned with are the 1-2 and 2-3 shift solenoids.

Depending on the type of scan tool you're using (either a generic scan tool or a professional level technician's scan tool), you may see that:

• Shift solenoid A is called 1-2 shift solenoid.
• Shift solenoid B is called 2-3 shift solenoid.

In this tutorial, I'll simply be identifying them as shift solenoid A or B. In the photos I'm using:

• Shift solenoid A (1-2 shift solenoid) is identified by the letter A.
• Shift solenoid B (2-3 shift solenoid) is identified by the letter B.

The PCM (Powertrain Control Module = Fuel Injection Computer) activates and deactivates these two solenoids in a predetermined pattern so that 4 specific gear ratios can be achieved. These are:

• 1st Gear: Solenoid 1-2: ON     Solenoid 2-3: ON
• 2st Gear: Solenoid 1-2: OFF   Solenoid 2-3: ON
• 3st Gear: Solenoid 1-2: OFF   Solenoid 2-3: OFF
• 4st Gear: Solenoid 1-2: ON     Solenoid 2-3: OFF

When any one of these two shift solenoids fail, the PCM commands the transmission to operate in LIMP IN MODE and this means that the transmission will run in 2nd gear only (no 1st and no 3rd or 4th).

Where To Buy The Shift Solenoid

It's a good idea, due to the amount of work involved in replacing the shift solenoids, that you don't buy brand-x (knock-off) shift solenoids.

The following shift solenoids are known-brand shift solenoids (AC-Delco is the factory original manufacturer):

Symptoms Of A Bad Shift Solenoid

The most common one is the check engine light will be on with one of the following diagnostic trouble codes:

• P0751 1-2 Shift Solenoid Valve Performance (Shift Solenoid A Performance)
• P0753 1-2 Shift Solenoid Valve Electrical (Shift Solenoid A Electrical)
• P0756 2-3 Shift Solenoid Valve Performance (Shift Solenoid B Performance)
• P0758 2-3 Shift Solenoid Valve Electrical (Shift Solenoid B Electrical)
• Transmission runs only in 2nd gear. This is known as running in LIMP IN MODE.

The most important thing to remember, when trying to decide if you have a solenoid issue or internal transmission damage (causing the transmission to stay in Limp-In mode) is two very important things:

1. You'll have a specific transmission solenoid trouble code stored in the PCM's memory.
2. The transmission doesn't ‘slip’.

OK, with this bit of info under our belts, let's turn the page and get testing!