P1743: Transmission Pressure Control Solenoid Malfunction

P1743: Transmission Pressure Control Solenoid Malfunction

Table of Contents 1. What is P1743? 2. Common Causes & Real Examples 3. Key Symptoms 4. Vehicles Prone to P1743 5. Diagnostic Steps 6. Fixes & Execution 7. Repair Costs & Safety Tips 8. Preventive Maintenance 9. Frequently Asked Questions 10. Summary
Diagnostic Guide

P1743: Transmission Pressure Control Solenoid Malfunction

P1743 indicates issues with your transmission's pressure control solenoid, often causing shifting delays or harshness. This guide breaks down causes, step-by-step diagnostics, and fixes—optimized for use with the iCarzone UR800 scanner.

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P1743

1. What is P1743?

P1743 is a manufacturer-specific Diagnostic Trouble Code (DTC) related to the Transmission Pressure Control Solenoid. This solenoid regulates hydraulic pressure in automatic transmissions, ensuring smooth gear shifts by controlling fluid flow to clutch packs and bands.

Why It Matters

A malfunctioning pressure control solenoid disrupts proper pressure regulation, leading to poor shift quality, overheating, or even transmission damage if ignored. Most commonly, P1743 indicates the solenoid is "stuck closed" or not responding to commands from the Transmission Control Module (TCM).

Typical triggers: solenoid electrical failure, clogged valve body, low transmission fluid, or TCM communication errors.

2. Common Causes & Real Examples

P1743 stems from electrical or mechanical issues in the transmission's pressure control system. Here are proven root causes with field examples:

  • Faulty Pressure Control Solenoid — Example: 2014 Ford F-150 with 6R80 transmission threw P1743 after solenoid coil burnout; replacing the solenoid resolved shifting issues.
  • Clogged Solenoid Valve — Example: 2016 Dodge Journey with contaminated transmission fluid (due to delayed service) had debris blocking the solenoid, causing pressure irregularities.
  • Damaged Wiring/Connectors — Example: 2015 Chevrolet Equinox showed P1743 after water intrusion corroded the solenoid connector; cleaning and sealing fixed the code.
  • Low or Degraded Transmission Fluid — Example: 2017 GMC Acadia with 8-speed transmission: low fluid caused insufficient pressure, triggering P1743 during heavy acceleration.
  • TCM Software Glitch — Example: 2018 Ford Escape required a TCM reflash to correct miscommunication with the pressure solenoid, eliminating recurring P1743.
P1743 Error Code: The Definitive Explanation You Need – iCarsoft-us

3. Key Symptoms

If P1743 is present, you may notice these warning signs:

  • Harsh or delayed gear shifts (especially when accelerating)
  • Transmission slipping between gears
  • Check Engine Light or Transmission Warning Light illuminated
  • Reduced fuel efficiency due to inefficient shifting
  • Overheating transmission (indicated by temperature warning)
Pro tip: Symptoms often worsen under load (e.g., towing, uphill driving) when pressure demands are highest.

4. Vehicles Prone to P1743

P1743 is most commonly reported in vehicles with specific transmission models. These include:

  • Ford F-150, F-250 (6R80, 5R110W transmissions)
  • Chevrolet Silverado, GMC Sierra (6L80, 8L90 transmissions)
  • Dodge Ram 1500 (545RFE, 8HP70 transmissions)
  • Ford Escape, Edge (6F35 transmission)
  • Volkswagen Tiguan, Golf (DSG transmissions)

Check manufacturer Technical Service Bulletins (TSBs) for your model—many have updated solenoids or TCM software to address P1743.

5. Diagnostic Steps

Accurate diagnosis requires a systematic approach. Use the iCarzone UR800 for live data and follow this flow:

Step Action Tools Needed Goal
1 Scan DTCs & Live Data iCarzone UR800 scanner Confirm P1743 and check for related codes (e.g., P0700, P1744)
2 Check Transmission Fluid Dipstick, fluid test strip Verify level, color, and contamination
3 Inspect Solenoid Wiring Multimeter, wire brush Check for corrosion, breaks, or loose connections
4 Test Solenoid Resistance Ohmmeter Ensure resistance matches OEM specs (typically 10-30 ohms)
5 Monitor TCM Commands UR800 (live PID data) Confirm TCM is sending voltage signals to the solenoid

Example: A 2015 Ford F-150 with P1743 showed normal fluid and wiring, but UR800 live data revealed the TCM wasn’t sending voltage to the solenoid. A TCM reflash (per Ford TSB) resolved the issue.

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6. Fixes & Execution

  • Replace Pressure Control Solenoid: When resistance is out of spec or the valve is stuck.
  • Flush Transmission Fluid: For contaminated fluid blocking the solenoid or valve body.
  • Repair Wiring/Connectors: Clean corrosion, replace damaged wires, and apply dielectric grease.
  • TCM Reprogramming: If software is outdated or causing communication errors.
  • Valve Body Service: For severe clogs requiring professional cleaning or replacement.

Recommended Workflow

  1. Use UR800 to confirm P1743 and rule out TCM communication issues.
  2. Check fluid first—low/degraded fluid is the easiest fix.
  3. Test wiring and solenoid resistance before replacing parts.
  4. Reflash TCM if manufacturer updates are available.

7. Repair Costs & Safety Tips

  • Pressure Solenoid (OEM): $80–$250
  • Transmission Fluid Flush: $150–$300
  • Wiring Repair: $70–$200
  • TCM Reprogramming: $100–$250
  • Valve Body Service: $300–$800

Safety Precautions

  • Disconnect the battery before working on transmission electrical components.
  • Let the transmission cool completely before opening fluid lines to avoid burns.
  • Use manufacturer-specified fluid to prevent further solenoid damage.
  • Clear codes with UR800 after repairs and test drive to confirm fixes.

8. Preventive Maintenance

Avoid P1743 with these proactive steps:

  • Change transmission fluid at OEM-recommended intervals (typically 60,000–100,000 miles).
  • Inspect solenoid connectors during routine service for corrosion.
  • Use the iCarzone UR800 quarterly to scan for pending codes before they trigger the Check Engine Light.
  • Avoid aggressive driving when the transmission is cold—let it warm up for smooth pressure regulation.
  • Address minor shifting issues immediately to prevent solenoid strain.

9. Frequently Asked Questions

Can I drive with P1743?

Short-term, but prolonged driving may cause transmission damage. Avoid heavy loads or high speeds until repaired.

Will changing fluid fix P1743?

If caused by contamination, yes. But if the solenoid is electrically faulty, fluid changes alone won’t resolve it.

Is P1743 only a Ford code?

No, but it’s most common in Ford vehicles. Other makes may use it for similar solenoid issues.

How does UR800 help with P1743?

UR800 reads live TCM data, tests solenoid signals, and clears codes—critical for accurate, fast diagnosis.

10. Summary

P1743 points to a pressure control solenoid issue in your transmission, causing poor shifting and potential damage. Diagnose systematically: check fluid, scan with UR800 for live data, test wiring/solenoid resistance, and address root causes (fluid, solenoid, or TCM). Timely repairs restore smooth performance and prevent costly transmission failure.

Fix P1743 Faster with UR800

The iCarzone UR800 lets you read live transmission data, test solenoid signals, and clear codes—all essential for resolving P1743 quickly. Trusted by DIYers and mechanics alike.

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