AutoCodes – Buick – P0742 Buick

P0742 Buick Code - Torque Converter Clutch System Stuck On Or Transmission Hydraulic/Mechanical Performance

Quick Answer

The Torque Converter Clutch (TCC) pressure control solenoid is part of the control solenoid valve assembly which has no serviceable parts. Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Control Solenoid Valve Assembly. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0742 Buick indicates Torque Converter Clutch System Stuck On Or Transmission Hydraulic/Mechanical Performance.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Control Solenoid Valve Assembly.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 44,848

How popular is this code, among other codes? Medium

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 30, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0742 Buick Description

The Torque Converter Clutch (TCC) pressure control solenoid is part of the control solenoid valve assembly which has no serviceable parts. The TCC pressure control solenoid is a normally low-pressure control solenoid. The TCC pressure control solenoid regulates the transmission fluid to the TCC regulator valve in the lower valve body and the TCC control valve in the pump cover. When vehicle operating conditions are appropriate to apply the converter clutch, the Transmission Control Module (TCM) will increase TCC pressure control current flow (duty cycle) to the TCC solenoid. The TCC pressure control solenoid directs fluid pressure to move the TCC control valve to the apply position and moves the TCC regulator apply valve to the regulating position. The TCC regulator valve regulates TCC apply fluid pressure proportional to TCC solenoid pressure. When the TCC is fully applied, the engine is coupled directly to the transmission. TCC release is accomplished by the Transmission Control Module decreasing current flow to the TCC pressure control solenoid. This results in decreasing the applied pressure which allows the TCC control valve to move to the release position. The Transmission Control Module calculates torque converter slip speed based on engine speed and transmission input shaft speed.
The Diagnostic Trouble Code (DTC) will be set when the CM detects the TCC slip between −50 and +13 RPM for 6 s when the TCC is commanded OFF.

OBDII Code P0742 Buick - Torque Converter Clutch System Stuck On Or Transmission Hydraulic/Mechanical Performance - AutoCodes.com — P0742 Buick Code - Torque Converter Clutch System Stuck On Or Transmission Hydraulic/Mechanical Performance

What does this mean?

What are the Possible Causes of the DTC P0742 Buick?

Low transmission fluid level
Dirty transmission fluid
Faulty Control Solenoid Valve Assembly
Control Solenoid Valve Assembly harness is open or shorted
Control Solenoid Valve Assembly circuit poor electrical connection
Transmission internal mechanical problem

How to Fix the DTC P0742 Buick?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

When a transmission solenoid is stuck on, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is very dirty, it is recommended to change the transmission fluid and if possible, remove the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a transmission mechanical failure, and that the transmission will need to be rebuilt or replaced.

There is a factory service bulletin for the following Buick Models:
2001-2005 Buick LeSabre
2001-2005 Buick Park Avenue
2002-2007 Buick Rendezvous
2002-2007 Buick Rendezvous AWD
2005-2007 Buick Terraza
2005-2007 Buick Terraza EXT
2005-2007 Buick Terraza 4WD
2005-2008 Buick Allure (Canada Only)
2005-2008 Buick LaCrosse
2006-2008 Buick Lucerne
Buick Factory Service Bulletin OBDII Code P0742

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0742 Buick code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0742 Buick code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0742 Buick Code

1. What are the common symptoms of OBDII code P0742 in a Buick related to the Torque Converter Clutch System?

The common symptoms include harsh shifting, decreased fuel efficiency, and the vehicle feeling like it's struggling to accelerate.

2. What are the possible causes of OBDII code P0742 in a Buick indicating Torque Converter Clutch System Stuck On or Transmission Hydraulic/Mechanical Performance issues?

Possible causes may include a faulty torque converter clutch solenoid, low transmission fluid levels, a malfunctioning torque converter, or internal transmission damage.

3. How can I diagnose OBDII code P0742 in my Buick if the Torque Converter Clutch System is stuck on or there are transmission performance issues?

Diagnosis involves using a scan tool to read the code, checking transmission fluid levels and condition, inspecting the torque converter clutch solenoid, and performing a thorough transmission system inspection.

4. What are the repair options for resolving OBDII code P0742 in a Buick related to the Torque Converter Clutch System?

Repair options may include replacing the torque converter clutch solenoid, addressing any transmission fluid leaks, repairing or replacing the torque converter, or conducting a full transmission rebuild if necessary.

5. Can driving with OBDII code P0742 in a Buick cause further damage to the vehicle?

Continuing to drive with this code may lead to increased wear on the transmission components, reduced fuel efficiency, and potential loss of power over time. It is recommended to address the issue promptly.

6. Are there any DIY tips for addressing OBDII code P0742 in a Buick at home?

While some basic checks like inspecting transmission fluid levels can be done at home, diagnosing and repairing the specific issue causing the code typically requires professional knowledge and tools. It's advisable to consult a qualified mechanic.

7. How much does it cost to repair OBDII code P0742 in a Buick at a dealership or repair shop?

The cost of repairing this code can vary depending on the specific cause, parts needed, and labor costs. It's recommended to obtain multiple quotes from reputable repair shops to compare prices.

8. Is OBDII code P0742 in a Buick a common issue, and are there any recalls related to this problem?

While the code may occur in some Buick vehicles, it is not necessarily a widespread issue. It's advisable to check with Buick or the National Highway Traffic Safety Administration (NHTSA) for any related recalls.

9. Can resetting the OBDII code P0742 in a Buick fix the issue temporarily?

Resetting the code may temporarily turn off the check engine light, but it will not address the underlying problem causing the code. It's crucial to diagnose and repair the issue to prevent further damage.

10. How long does it typically take to repair OBDII code P0742 in a Buick at a professional repair shop?

The repair time can vary depending on the complexity of the issue, availability of parts, and the shop's workload. In some cases, it may take a few hours to a full day to diagnose and repair the problem.

Discuss the causes and fixes for P0742 Buick OBDII Code

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Juan Ramos
Date: February 22, 2017 at 10:36 pm

The check engine soon light turn on after I run the drive cycle on my 2002 Buick Rendezvous cx the code say that the torque convert stuck on

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