Diagnosis & Repair

2004 Toyota Celica GT, StandardSECTION Diagnosis & Repair
WARNING: This page is about a different car, the 2003 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: If DTC P1600 exists, the ECM will not store any other DTCs. Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.

For circuit wiring diagram, diagnosis and repair procedure, see Fig 1.

When access to, or replacement of ECM is necessary, Engine Control Module (ECM) is located behind glove box. See Figure. For ECM connector terminal view, see Figure.

For removal and installation of components, see REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

Fig 1: DTC P1600 Diagnostic Procedure
G00247646Courtesy of Β© TOYOTA, LICENSE AGREEMENT TMS1002
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.