Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2006 Toyota Sienna CEFACTORY OEM SERVICE PROCEDURE
Problem Symptoms Table
SFI SYSTEM
PROBLEM SYMPTOMS REFERENCE
| Symptom | Suspected area | See |
|---|---|---|
| Engine does not crank (Does not start) | 1. Starter | INSPECTION |
| 2. ST relay | INSPECTION | |
| 3. Park/neutral position switch (U151E) | INSPECTION | |
| 4. Park/neutral position switch (U151F) | INSPECTION | |
| No initial combustion (does not start) | 1. ECM power source circuit | ECM POWER SOURCE CIRCUIT |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. ECM | - | |
| 4. VC output circuit | VC OUTPUT CIRCUIT | |
| No complete combustion (does not start) | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| Difficult to start (engine cranks normally) | 1. Starter signal circuit | DTC P0617 STARTER RELAY CIRCUIT HIGH |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. Compression | ON-VEHICLE INSPECTION | |
| Difficult to start with cold engine | 1. Starter signal circuit | DTC P0617 STARTER RELAY CIRCUIT HIGH |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| Difficult to start with hot engine | 1. Starter signal circuit | DTC P0617 STARTER RELAY CIRCUIT HIGH |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| High engine idle speed (poor idling) | 1. A/C signal circuit (Compressor circuit) | AIR CONDITIONING COMPRESSOR MAGNETIC CLUTCH CIRCUIT |
| 2. ECM power source circuit | ECM POWER SOURCE CIRCUIT | |
| Low engine idle speed (poor idling) | 1. A/C signal circuit (Compressor circuit) | AIR CONDITIONING COMPRESSOR MAGNETIC CLUTCH CIRCUIT |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| Rough idling (poor idling) | 1. Compression | ON-VEHICLE INSPECTION |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| 3. Mass air flow meter | MASS AIR FLOW METER | |
| Hunting (poor idling) | 1. ECM power source circuit | ECM POWER SOURCE CIRCUIT |
| 2. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT | |
| Hesitation/Poor acceleration (poor driveability) | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| 2. Mass air flow meter | MASS AIR FLOW METER | |
| 3. A/T faulty (U151E) | HOW TO PROCEED WITH TROUBLESHOOTING | |
| 4. A/T faulty (U151F) | HOW TO PROCEED WITH TROUBLESHOOTING | |
| Surging (poor driveability) | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| 2. Mass air flow meter | MASS AIR FLOW METER | |
| Engine stalls soon after starting | 1. Fuel pump control circuit | FUEL PUMP CONTROL CIRCUIT |
| Engine stalls during A/C operation | 1. A/C signal circuit (Compressor circuit) | AIR CONDITIONING COMPRESSOR MAGNETIC CLUTCH CIRCUIT |
| 2. ECM | - | |
| Unable to refuel/Difficult to refuel | 1. ORVR system | - |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.