AutoCodes – Isuzu – P0742 Isuzu

P0742 Isuzu Code - Torque Converter Clutch Circuit Stuck On

Quick Answer

The Torque Converter Clutch (TCC) solenoid valve is activated, with the gear in D4, by the Transmission Control Module (TCM) in response to signals sent from the vehicle speed and the Engine Control Module (ECM). Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty torque converter clutch solenoid valve. 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 Isuzu indicates Torque Converter Clutch Circuit Stuck On.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty torque converter clutch solenoid valve.
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 8,244

How popular is this code, among other codes? Low

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 Jun 14, 2020

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

The Torque Converter Clutch (TCC) solenoid valve is activated, with the gear in D4, by the Transmission Control Module (TCM) in response to signals sent from the vehicle speed and the Engine Control Module (ECM). Lock-up piston operation will then be controlled. When the torque converter clutch solenoid valve is activated, the torque converter lockup clutch will engage creating a 1 to 1 RPM ratio between the transmission input shaft and the rotational speed of the torque converter.
Lock-up operation, however, is prohibited when A/T fluid temperature is too low.
When the accelerator pedal is depressed (less than 2/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.

OBDII Code P0742 Isuzu - Torque Converter Clutch Circuit Stuck On - AutoCodes.com — P0742 Isuzu Code - Torque Converter Clutch Circuit Stuck On

What does this mean?

What are the Possible Causes of the DTC P0742 Isuzu?

Low transmission fluid level
Dirty transmission fluid
Faulty torque converter clutch solenoid valve
Torque converter clutch solenoid valve harness or connectors
Torque converter clutch solenoid valve circuit is open or shorted
Transmission internal mechanical problem

How to Fix the DTC P0742 Isuzu?

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 the 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 recommend changing the transmission fluid and if possible removing 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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0742 Isuzu 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 Isuzu 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 Isuzu Code

1. What are the common symptoms of OBDII code P0742 in an Isuzu vehicle?

Symptoms may include engine stalling at idle, difficulty shifting gears, decreased fuel efficiency, and a noticeable decrease in overall vehicle performance.

2. What does the OBDII code P0742 - Torque Converter Clutch Circuit Stuck On mean for an Isuzu?

This code indicates that the vehicle's powertrain control module has detected a problem with the torque converter clutch circuit remaining engaged when it should be disengaged.

3. What are the possible causes of OBDII code P0742 in an Isuzu?

Potential causes include a faulty torque converter clutch solenoid, wiring issues in the circuit, a malfunctioning torque converter, low transmission fluid levels, or a failing transmission control module.

4. How serious is the OBDII code P0742 on an Isuzu?

While the vehicle may still be operable with this code present, it is important to address the issue promptly to prevent further damage to the transmission and ensure optimal vehicle performance.

5. Can I continue driving my Isuzu with the OBDII code P0742 present?

It is not recommended to continue driving the vehicle with this code present, as it can lead to increased wear on the transmission components and potential drivability issues.

6. How can I diagnose the root cause of OBDII code P0742 in my Isuzu?

Diagnosis typically involves a thorough inspection of the torque converter clutch solenoid, checking the wiring for any damage or loose connections, verifying transmission fluid levels, and potentially performing a transmission pressure test.

7. What are some repair tips for addressing OBDII code P0742 in an Isuzu?

Repair tips may include replacing the torque converter clutch solenoid, repairing any damaged wiring in the circuit, ensuring proper transmission fluid levels, and resetting the trouble code after the repairs are completed.

8. Is it possible to reset the OBDII code P0742 in an Isuzu without repairing the issue?

While clearing the trouble code may temporarily turn off the Check Engine light, it is not recommended to reset the code without addressing the underlying problem, as it is likely to return and potentially cause more severe issues.

9. How much does it typically cost to repair OBDII code P0742 in an Isuzu?

The cost of repairs can vary depending on the exact cause of the issue, but it may range from a few hundred to over a thousand dollars, including parts and labor.

10. Can OBDII code P0742 in an Isuzu be prevented?

Regular maintenance, such as checking and changing transmission fluid at recommended intervals, can help prevent issues that may lead to the occurrence of this trouble code.