Toyota OBD/OBD2 Codes >> Previa 2.4L (1991 – 1995)

Model Year Engine identification System
Previa 2.4L 1991-95 2TZ-FE   TCCS

General information

  • Engine control module (ECM) incorporates self-diagnosis function.
  • Malfunction indicator lamp (MIL) will illuminate if certain faults are recorded.
  • ECM operates in backup mode if sensors fail, to enable vehicle to be driven to workshop.
  • ECM trouble codes can be accessed with suitable code reader connected to the data link connector (DLC) [1] or displayed by the MIL.


  • Switch ignition ON. Do NOT start engine.
  • Check MIL illuminates.
  • Switch ignition OFF.
  • Jump DLC terminals TE1 and E1 0
  • Switch ignition ON.
  • Count MIL flashes and compare with trouble code table.
  • First flashes of 0.5 second duration indicate ‘tens’, after a 1.5 second pause, next flashes of 0.5 second duration indicate ‘units'[2]
  • A 2.5 second pause occurs between codes.
  • After a 4.5 second pause, trouble codes will be repeated.

NOTE: The MIL flashes once every 0.25 seconds if the system is correct [3].

  • Switch ignition OFF.
  • Remove jump lead.

Preparatory conditions

  • Battery voltage 11 V minimum.
  • Closed throttle position (CTP) switch fully closed.
  • Transmission in neutral position.
  • All auxiliary equipment, including air conditioning, switched OFF.
  • Engine at normal operating temperature.


  • Ensure ignition switched OFF.
  • Remove EFI fuse (15A) from fascia fusebox 19.
  • Wait 30 seconds.
  • Reinstall fuse.
  • Repeat checking procedure to ensure no data remains in ECM fault memory.

NOTE: Disconnecting battery ground lead will also erase trouble codes but may erase memory from electronic units such as radio.

Trouble code identification

Flash code

Fault location

Probable cause


Engine speed (RPM) sensor – circuit

Wiring, RPM sensor, ignition module, ECM


Engine speed (RPM) sensor- above

1000 rpm

Wiring, RPM sensor, ECM


Ignition reference signal – no signal

Wiring, ignition module, ECM


Heated oxygen sensor (H02S) -front -circuit

Wiring, H02S, ECM


Engine coolant temperature (ECT) sensor – circuit

Wiring, ECT sensor, ECM


Intake air temperature (IAT) sensor- circuit

Wiring, IAT sensor, ECM


Mixture control – continuously lean

Wiring, injector, H02S, ECTNAF sensor, intake/fuel/ignition system, ECM


Mixture control – continuously rich

Wiring, injector, fuel system, cold start injector, H02S, ECTNAF sensor, ECM


Heated oxygen sensor (H02S) – rear- circuit

Wiring, H02S, ECM


Volume air flow (VAF) sensor – circuit

Wiring, VAF sensor, ECM


Volume air flow (VAF) sensor- circuit

Wiring, VAF sensor, ECM


Throttle position (TP) sensor- circuit

Wiring, TP sensor, ECM


Vehicle speed sensor. (VSS) – circuit

Wiring, VSS, ECM


Starter signal – circuit

Wiring, ignition switch, engine control relay, ECM


Switch signal – closed throttle position (CTP)

switch OFF during diagnosis

Wiring, CTP switch, ECM


Switch signal – park/neutral position (PNP)

switch not in P or N during diagnosis

Wiring, PNP switch, ECM


Knock sensor (KS) – circuit

Wiring, KS, ECM


Knock control – malfunction



Exhaust gas recirculation (EGR) system – malfunction

Hose leak/blockage, wiring, EGRT sensor, EGR solenoid, ECM