2004 Toyota PriusFACTORY OEM SERVICE PROCEDURE

Problem Symptoms Table

When the malfunction is not confirmed in the diagnostic trouble code check and the problem still can not be confirmed in the basic inspection, use this table and troubleshoot according to the priority order given below.

PROBLEM SYMPTOMS TABLE - SFI SYSTEM

Symptom Suspected Area
Engine does not crank (Does not start)
  • 26. MG1
  • 27. Hybrid system
  • 28. Immobilizer
  • 29. Push start system
No initial combustion (Does not start)
  1. ECM power source circuit
  2. Fuel pump control circuit
  3. Spark plug
  4. Immobilizer system
  5. Injector
  6. ECM
  7. Crankshaft position sensor circuit
No complete combustion (Does not start)
  1. Fuel pump control circuit
  2. Spark plug
  3. Immobilizer system
  4. Injector
  5. Crankshaft position sensor circuit
Engine cranks normally but difficult to start
  1. Fuel pump control circuit
  2. Compression
  3. Spark plug
  4. Injector
  5. Crankshaft position sensor circuit
Difficult to start with cold engine
  1. Fuel pump control circuit
  2. Spark plug
  3. Injector
  4. Crankshaft position sensor circuit
Difficult to start with hot engine
  1. Fuel pump control circuit
  2. Spark plug
  3. Injector
  4. Crankshaft position sensor circuit
High engine idle speed (Poor idling)
  1. ECM power source circuit
  2. Electronic throttle control system
Low engine idle speed (Poor idling)
  1. Fuel pump control circuit
  2. Electronic throttle control system
  3. Injector
Rough idling (Poor idling)
  1. Compression
  2. Electronic throttle control system
  3. Injector
  4. Fuel pump control circuit
  5. Spark plug
Hunting (Poor idling)
  1. ECM power source circuit
  2. Electronic throttle control system
  3. Fuel pump control circuit
Hesitation/Poor acceleration (Poor driveability)
  1. Fuel pump control circuit
  2. Injector
  3. Spark plug
  4. HV transaxle
Surging (Poor driveability)
  1. Fuel pump control circuit
  2. Spark plug
  3. Injector
Engine stalls soon after starling
  1. Fuel pump control circuit
  2. Electronic throttle control system
  3. Immobilizer
  4. Crankshaft position sensor circuit
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.