⚙️ Critical Role of Solenoid “E”
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Controls hydraulic pressure in the valve body
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Manages gear shifts for specific ratios (e.g., 4→5 or 5→6 on 6-speed)
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Fault → Disruption of shift sequences and transmission overheating
🚨 Immediate Symptoms
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Gear slipping (engine RPM surges without acceleration)
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Jolts when engaging (especially between 3rd and 4th gear)
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Transmission overheating (burning smell + temperature warning light)
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Limp mode activated (limited power, gears locked)
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Check Engine + Overdrive warning lights (⚠️ flashing on Ford)
🔧 Common Causes (Order of Probability)
| Rank | Cause | Details |
|---|---|---|
| 1 | Degraded transmission fluid | Low level, oxidation, metal contamination |
| 2 | Faulty Solenoid “E” | Burnt coil, stuck magnetized core |
| 3 | Damaged wiring | Chafed wires, corroded connectors (moisture) |
| 4 | Clogged valve body | Particles blocking jets |
| 5 | Internal failure | Burnt clutches, leaking seals |
| 6 | PCM failure | Rare (< 5%) – check companion codes |
🔍 Diagnostic Procedure
Step 1: Preliminary Checks (30 min)
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Fluid check:
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Level when hot (engine running)
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Color/smell: Bright red = OK, Brown/black + burnt smell = contamination
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Visual inspection:
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Solenoid connectors (green corrosion = water infiltration)
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Wiring along the transmission (look for chafed areas)
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Step 2: Electrical Tests
| Test | Tool | Normal Values |
|---|---|---|
| Solenoid resistance | Multimeter Ω | 20-30 Ω (depending on model) |
| Circuit continuity | Probe tester | 0 Ω (PCM → solenoid) |
| PCM voltage | DC multimeter (ignition ON) | 12V on power wire |
Step 3: Advanced Analysis
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OBD-II scanner specific to transmission (e.g., Ford IDS, Toyota TechStream):
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Monitor solenoid PIDs (% activation, current errors)
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Check line pressure (if sensor available)
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🛠️ Repairs & Costs
| Problem | Solution | Average Cost |
|---|---|---|
| Contaminated fluid | Drain + refill (flush if severe) | 150-300 € |
| Faulty solenoid | Replacement (OEM part) | 120-250 € |
| Damaged wiring | Harness repair | 80-180 € |
| Valve body cleaning | Removal/ultrasonic cleaning | 300-500 € |
| Transmission repair | Complete overhaul | 1500-3000 € |
⏱️ Service time: 2h (diagnosis) + 2h to 8h (repair).
⚠️ Risks of Ignoring the Code
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Clutch destruction (repeated slipping → overheating)
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Transmission lock-up in limp mode
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Engine overheating (improper gear ratios → excessive RPM)
🔧 Pro Tips
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First action:
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Check manufacturer TSB (e.g., Ford TSB #19-2367 on false P0773 for 2018 Focus)
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Quick test:
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Disconnect solenoid connector → If code changes from P0773 to P0774, the solenoid is faulty.
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Critical parts:
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Solenoid “E” Aisin TCC-SOL-006 (Toyota/Lexus)
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Solenoid BorgWarner E47339 (Chrysler/Dodge)
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Common mistake:
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Forgetting to reset adaptations after repair (required on 80% of models)
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📊 Workshop Statistics: 70% of P0773 resolved by solenoid replacement + complete fluid change.
Conclusion:
P0773 indicates a critical electrical or hydraulic fault. Recommended procedure:
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Check fluid level/condition
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Test solenoid resistance + wiring continuity
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Replace solenoid if faulty → Reset PCM
Do not delay repair: Prolonged slipping costs 10x more in a full overhaul!