Engine Codes
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DIAGNOSTIC SYSTEM DESCRIPTION

The ECU contains a built-in self-diagnosis system by which troubles with the engine signal network are detected and a " Check Engine" warning light on the instrument panel flashes.

By analyzing various signals as shown in the later tables, the Electronic Control Unit (ECU) detects system malfunctions which are related to the various operating parameter sensors or to the actuator. The ECU stores the failure until the diagnosis system is cleared by removing the EFI fuse with the ignition switch off. A "Check Engine" warning light on the instrument panel informs the driver that a malfunction has been detected. The light goes out automatically when the malfunction has been cleared.

"CHECK ENGINE" WARNING LIGHT
The "Check Engine" warning light will come on when the ignition switch is placed at ON and the engine is not running.

  1. When the engine is started, the "Check Engine" warning light should go out. If the light remains on, the diagnosis system has detected a malfunction or abnormality in the system.

OUTPUT OF DIAGNOSTIC CODES
To obtain an output of diagnostic codes, proceed as follows:

  1. Initial Conditions
    1. Battery voltage above 11 volts
    2. Throttle valve fully closed (throttle position sensor IDL points closed)
    3. Transmission in neutral position
    4. Accessory switches off
  1. Turn the Ignition Switch to ON. Do not start the engine.
  2. Using a service wire, connect terminals TE1 and E1 of the check connector.

NOTE: The check connector is located near the ignition coil.

Read the diagnostic code as indicated by the number of flashes of the "Check Engine" warning light.

Diagnostic Code

  1. Normal System Operation (no malfunction)
    • The light will alternately blink on and off for 0.26 second intervals.
  2. Malfunction Code Indication
    • In the event of a malfunction, the light will blink every 0.52 seconds. The first number of blinks will equal the first digit of a 2-digit diagnostic code and, after a 1.5 second pause, the 2nd number of blinks will equal the 2nd. If there are two or more codes, there will be a 2.5 second pause between each.
    • After all the codes have been signaled there will be a 4.5 second pause and they will all be repeated as long as the terminals TE1 and E1 of the check connector are connected.

NOTE: In the event of a number of trouble codes, indication will begin from the smaller value and continue to the larger.

  1. After the diagnosis check, remove the service wire.

 

CANCELLING OUT DIAGNOSTIC CODE

  1. After repair of the trouble area, the diagnostic code retained in memory by the ECU can be canceled out by removing the 15A EFI fuse for 30 seconds or more, depending on ambient temperature (the lower the temperature, the longer the fuse must be left out) WITH THE IGNITION SWITCH OFF.

NOTE:

  • Cancellation can also be accomplished by disconnecting the battery of the car but in this case, other system's memory will also be affected (radio ETR, clock, etc.).
  • If the diagnostic code is not canceled out, it will be retained by the ECU and will appear along with a new code in the event of future trouble.
  • If it is necessary to work on engine components requiring disconnecting the battery , a check should be made to see if a diagnostic code has been recorded, as it will be lost upon disconnection of the battery.
  • After cancellation, road test the vehicle to confirm that the "normal" code is now read on the "Check Engine" warning light. If the same diagnostic code is still indicated, it means that the trouble area has not yet been repaired thoroughly.

DIAGNOSIS INDICATION
When 2 or more codes are indicated, the lowest number (code) will appear first. HOWEVER, NO OTHER CODE WILL APPEAR WITH CODE NO.11.

  1. All detected diagnostic codes, except 51 and 53, will be retained in memory by the ECU from the time of detection until cancellation.
  2. Once a malfunction is cleared, the "Check Engine" warning light on the instrument panel will go out but the diagnostic code(s) remain(s) stored in ECU memory (except for codes 51 and 53).
Code No. System Diagnosis Trouble Area
--- Normal This appears when none of the other codes are identified --
11 ECU (+B) Momentary interruption in power supply to ECU Ignition switch circuit Ignition switch Main relay circuit Main relay ECU
12 RPM Signal No "NE" or "G" signal to ECU within 2 seconds after engine has been cranked Distributor (cam position sensor) circuit Distributor (cam position sensor) Starter signal circuit ECU
13 RPM Signal No "NE" signal to ECU when engine speed is above 1000 RPM. Distributor (cam position sensor) circuit Distributor (cam position sensor) ECU
14 Ignition Signal No "IGF" signal to ECU "A" times in succession. "A" = : 7M-GE 6-8 7M-GTE 3 Igniter and ignition coil circuit Igniter and ignition coil ECU
21 Oxygen Sensor Signal Detection of oxygen sensor deterioration. Oxygen sensor circuit Oxygen sensor ECU
22 Water Temp sensor signal Open or short circuit in water temp sensor signal (THW). Water Temp Sensor circuit Water Temp Sensor ECU
24 Intake Air Temp Sensor Signal Open or short circuit in Intake air temp sensor signal (THA). Intake air Temp Sensor Circuit Intake air Temp Sensor ECU
*1 25 *1 26 Air-Fuel Ratio LEAN Malfunction Air-Fuel Ratio Rich Malfunction When Air-Fuel ratio feedback compensation value or adaptive control value continues at the upper (lean) or lower (rich) limit renewed for a certain period of time. When Air-Fuel ratio feedback compensation value or adaptive control value feedback frequency is abnormally high during feedback condition. When marked variation is detected in engine revolutions for each cylinder during idle switch on and feedback condition. NOTE: For conditions (2) and (3), since neither a lean (Code 25) or rich (Code 26) Diagnosis displayed consecutively. Injector circuit Injector Fuel line pressure Air Flow Meter Air Intake System Cold Start Injector Oxygen Sensor Circuit Oxygen Sensor Ignition System Water temp sensor ECU
*2 27 Sub-Oxygen Sensor Signal Sub-Oxygen Sensor Heater Open or short circuit in sub-oxygen sensor signal (OX2) Open or short circuit in sub-oxygen sensor heater signal (HT) Sub-oxygen sensor circuit Sub-oxygen sensor ECU Sub-oxygen sensor heater circuit Sub-oxygen sensor heater ECU
31 Air Flow Meter Signal (7M-GE) Open Circuit in VC signal or short circuit between VS and E2 when idle contacts are closed. (7M-GTE) Open or short circuit in air flow meter signal. Air flow meter circuit Air flow meter ECU
32 (7M-GE) Air Flow Meter Signal (7M-GTE) HAC Sensor Signal Open Circuit in E2 or short circuit between VC and VS Open or short circuit in HAC sensor signal Air Flow meter circuit Air Flow meter ECU ECU
*3 34 Turbo Pressure *4 The turbocharger pressure is abnormal Turbocharger Air flow meter ECU Intercooler system
41 Throttle position sensor signal Open or short circuit in throttle position sensor signal Throttle position sensor circuit Throttle position sensor ECU
42 Vehicle speed sensor signal No "SPD" signal to ECU for 8 seconds when engine speed is between 2,500 and 4,500 (7M-GE) or 4,000 (7M-GTE) rpm and coolant temp is below 80 deg C(176 deg F) and neutral start switch is off Vehicle speed sensor circuit Vehicle speed sensor ECU
43 Starter signal No "STA" signal to ECU until engine speed reaches 800 rpm with vehicle not moving Ignition switch circuit Ignition switch ECU
52 Knock sensor signal Open or short circuit in knock sensor signal. Knock sensor circuit Knock sensor ECU
53 Knock control signal in ECU Knock control program faulty ECU
*5 71 EGR System malfunction EGR gas temp below predetermined level during EGR operation Open Circuit in EGR gas temp sensor signal (THG) EGR system (EGR valve, EGR hose, etc.) EGR gas temp sensor circuit EGR gas temp sensor VSV for EGR VSV for EGR circuit ECU
51 Switch Signal No "IDL" signal, "NSW" signal or "A/C" signal to ECU during diagnostic check A/C switch circuit A/C switch A/C amplifier Throttle position sensor circuit Throttle position sensor ECU

*1 ex. 7M-GTE (Federal Vehicles) *2 7M-GE (California Vehicles) *3 7M-GTE *4 Abnormalities in the Air Flow Meter may also be detected *5 California Vehicles