The P1739 trouble code is a diagnostic trouble code (DTC) indicating an issue with the 3rd clutch pressure switch circuit in automatic transmission systems. This code is primarily associated with vehicles equipped with automatic transmissions and suggests that the Powertrain Control Module (PCM) has detected a malfunction in the pressure switch responsible for regulating hydraulic pressure in the transmission. If unresolved, this issue can lead to poor transmission performance, including slipping, rough shifting, or even complete transmission failure.
| P1739 Code Meaning | P1739 Code Common Causes |
|---|---|
| Problem in 3rd Clutch Pressure Switch Circuit | Faulty 3rd clutch pressure switch |
| Electrical fault in the circuit | Wiring issues or short circuits |
| PCM malfunction | Faulty connectors or corrosion |
| Transmission fluid issues | Internal transmission problems |
Symptoms of P1739 Code
The symptoms associated with the P1739 code can vary but typically include:
- Check Engine Light: The most common indication of a problem.
- Transmission Issues: Symptoms may include rough shifting, slipping gears, or delayed engagement when shifting from park to drive.
- Poor Acceleration: The vehicle may struggle to accelerate smoothly due to incorrect pressure readings.
- Unusual Transmission Behavior: This may involve erratic shifting patterns or failure to shift into certain gears.
Technical Explanations
The P1739 code indicates that the PCM has detected a fault in the 3rd clutch pressure switch circuit. This switch plays a critical role in controlling hydraulic pressure within the transmission. When the PCM receives signals that do not match expected values from this switch, it triggers the P1739 code.
How the Transmission Works
Automatic transmissions utilize hydraulic pressure to engage and disengage clutches and bands. The 3rd clutch pressure switch monitors this hydraulic pressure. If the switch fails or if there is an electrical fault in its circuit, the PCM cannot accurately determine the state of the transmission, leading to potential performance issues.
Step-by-Step Diagnosis
Diagnosing a P1739 code involves several steps:
- Scan for Codes: Use an OBD-II scanner to confirm the presence of the P1739 code and check for any additional codes that may provide more context.
- Visual Inspection: Inspect wiring and connectors associated with the 3rd clutch pressure switch for signs of damage, corrosion, or loose connections.
- Test Voltage: With the ignition on (engine off), check for voltage at the connector of the 3rd clutch pressure switch. You should see approximately 12 volts.
- Resistance Check: Disconnect the switch and measure resistance across its terminals. A functional switch should show high resistance (open circuit) when not engaged.
- Pressure Test: If possible, perform a hydraulic pressure test on the transmission to ensure it meets manufacturer specifications.
- Replace Components as Necessary: Based on your findings, replace any faulty switches, wiring, or connectors.
Solution Methods
To resolve a P1739 code, consider these solutions:
- Replace Faulty Switch: If diagnostics indicate that the 3rd clutch pressure switch is defective, it should be replaced.
- Repair Wiring Issues: Address any damaged wiring or corroded connectors found during your inspection.
- Check PCM: If all else fails and no physical issues are found, consider testing or replacing the PCM, as it may be misinterpreting signals from the transmission.
- Transmission Fluid Change: If fluid is old or contaminated, changing it can sometimes resolve shifting issues.
Cost Estimates
The cost to diagnose and repair a P1739 trouble code can vary widely based on location and vehicle type:
- Diagnostic Fees: Typically range from $100 to $150 at most shops.
- Switch Replacement: The part itself usually costs between $50 and $150, plus labor charges which can add another $75 to $150 depending on shop rates.
- Wiring Repairs: Costs can vary significantly based on damage but expect anywhere from $50 to $200 for repairs.
- PCM Replacement: This can be quite costly, ranging from $300 to over $1,000 depending on vehicle make and model.
Warnings and Recommendations
- Immediate Attention Required: If you encounter a P1739 code, it is crucial to address it promptly as continued driving can lead to severe transmission damage.
- Professional Help Advised: If you are not comfortable diagnosing or repairing electrical systems or transmissions, seek assistance from a qualified technician.
- Avoid DIY Risks: Attempting repairs without adequate knowledge can lead to further complications; always consult your vehicle’s service manual for guidance.
Closing Paragraph
The P1739 trouble code signifies an important issue within your vehicle’s transmission system that requires immediate attention. By understanding its implications and following systematic diagnostic steps, vehicle owners and DIY mechanics can effectively address this problem. Always prioritize safety and consider professional assistance when necessary to ensure reliable vehicle operation.
Frequently Asked Questions About P1739
- What does the P1739 code mean?
The P1739 code indicates a problem with the 3rd clutch pressure switch circuit in an automatic transmission. - Can I drive my car with a P1739 code?
It is not advisable to drive your vehicle with this code as it may lead to further transmission damage. - How much does it cost to fix a P1739 code?
The total cost can range from $100 for diagnostics up to $1,000 or more depending on necessary repairs. - What are common symptoms of a P1739 code?
Symptoms include check engine light activation, rough shifting, slipping gears, and poor acceleration. - How do I diagnose a P1739 code?
Diagnosis includes scanning for codes, inspecting wiring and connectors, testing voltage and resistance at the switch. - Is replacing the 3rd clutch pressure switch difficult?
This task can be complex; if unsure, it’s best left to professionals. - What causes a P1739 code?
Common causes include a faulty 3rd clutch pressure switch, wiring issues, or problems within the PCM. - Can low transmission fluid trigger a P1739 code?
Yes, low or contaminated fluid can affect hydraulic pressure readings leading to this error.