P0742 — Torque Converter Clutch Circuit Stuck On #

The code label may vary depending on the vehicle manufacturer.

• Torque Converter Clutch Circuit Stuck On (Generic/SAE)
• TCC Solenoid Circuit Stuck On (Chrysler, Dodge, Jeep)
• TCC Control Solenoid Valve Stuck On (Honda/Acura)
• Torque Converter Clutch Solenoid Valve Circuit On (GM/Chevrolet)
• Torque Converter Clutch Pressure Control Solenoid Stuck On (Ford/Lincoln)

Summary of the P0742 Code #

The P0742 Diagnostic Trouble Code (DTC) indicates that the Torque Converter Clutch (TCC) circuit is stuck in the “on” position. The torque converter clutch is a component within the automatic transmission that locks the engine and transmission together for better efficiency at cruising speeds. When the TCC circuit is “stuck on,” it means the clutch is not disengaging as commanded by the engine control module (ECM) or transmission control module (TCM). This can lead to drivability issues, such as stalling or harsh shifting, especially at low speeds or when coming to a stop. The ECM/TCM detects this fault by monitoring the clutch application via various sensors and electrical signals.

Common Symptoms for Code P0742 #

Code P0742 often presents noticeable symptoms that can affect your driving experience and vehicle performance. Drivers may notice the following:

• Engine stalling or near stall when coming to a stop
• Harsh or erratic shifting
• Poor fuel economy
• Illuminated Check Engine Light
• Transmission overheating in severe cases

Most Likely Causes for Code P0742 #

Several issues can trigger P0742, but some are more common than others. The following are ranked from most to least frequent:

1. Faulty Torque Converter Clutch Solenoid — The solenoid may be stuck in the “on” position or electrically shorted.
2. Wiring or Connector Problems — Damaged, corroded, or shorted wiring/connectors in the TCC circuit can cause false signals.
3. Transmission Fluid Contamination — Dirty, old, or low fluid can cause internal sticking of the solenoid or valve body.
4. Internal Transmission Issues — Problems with the valve body, worn clutches, or mechanical binding inside the transmission.
5. Faulty Transmission Control Module (TCM) or Engine Control Module (ECM) — Rare, but possible if all else checks out.

Step-by-Step Diagnostic Guide for P0742 #

A thorough and methodical approach is vital to correctly diagnose code P0742. Here’s a proven procedure:

• 1. Scan for Additional Trouble Codes: Check for related codes that may indicate broader transmission or electrical issues.
• 2. Inspect Transmission Fluid: Check fluid level, color, and smell. Replace if dirty, burnt, or contaminated.
• 3. Visual Inspection: Examine the harness and connectors at the transmission for damage, corrosion, or loose pins.
• 4. Test the TCC Solenoid: Use a multimeter to check resistance and continuity. Compare readings with OEM specifications.
• 5. Command Solenoid On/Off with a Scan Tool: If possible, use a professional scan tool to activate/deactivate the TCC solenoid and observe function.
• 6. Check for Internal Transmission Issues: If electrical tests pass, internal mechanical problems may be present. A pressure test or teardown might be necessary.
• 7. Inspect/Update TCM or ECM: As a last resort, consider software updates or replacement if all components test good.

Possible Repairs for Code P0742 #

Once you’ve pinpointed the cause, repair options for P0742 are generally straightforward and directly address the root issue:

• Replace the TCC Solenoid if testing reveals it is stuck or shorted.
• Repair or replace damaged wiring/connectors in the TCC circuit.
• Flush and replace transmission fluid if contamination is found; perform a filter change as needed.
• Repair internal transmission components such as the valve body or clutch assemblies if mechanical failure is present.
• Update or replace the TCM/ECM only if all other repairs fail to resolve the issue.

Is It Safe to Drive with Code P0742? #

Driving with code P0742 is generally not recommended. While the vehicle may still operate, the risk of stalling at stops, harsh shifting, and potential transmission overheating can lead to unsafe driving conditions or expensive damage. If you must drive, limit your distance and avoid heavy traffic or stop-and-go situations until the issue is resolved.

Vehicles Most Commonly Affected by P0742 #

While P0742 is a generic OBD-II code and can appear on any modern automatic transmission vehicle, it’s most frequently reported on:

• Chrysler, Dodge, and Jeep models (particularly with 42RLE, 45RFE, 62TE transmissions)
• GM/Chevrolet vehicles (especially those with 4L60E, 4T65E, and 6L80 transmissions)
• Honda/Acura models (notably with automatic V6 transmissions)
• Ford/Lincoln vehicles (including 4R70W, 5R55, and 6F35 transmissions)
• Toyota/Lexus models (with U-series transmissions)

Common Mistakes & Best Practices for P0742 #

The path to fixing P0742 can be tricky. Avoid these errors and follow these best practices:

• Don’t replace the transmission or TCC solenoid without confirming the root cause—always test wiring and fluid condition first.
• Don’t ignore additional codes; they may reveal underlying electrical or mechanical problems.
• Always use OEM or high-quality replacement parts for solenoids and connectors.
• Document all test results and repairs for future reference.

Quick FAQ for P0742 #

Q: Will clearing the code fix the problem?
A: No. Clearing the code without addressing the underlying cause will only temporarily turn off the warning. The code (and symptoms) will return.

Q: Can low or dirty transmission fluid cause P0742?
A: Yes. Contaminated or low fluid can cause the TCC solenoid or valves to stick, leading to this code. Always check and service the fluid as part of your diagnosis.