Subaru List of Diagnostic Trouble Code (DTC) OBD-I

This page contains OBD-I diagnostic trouble codes (DTCs) for Subaru vehicles manufactured before 1996.

🔹 OBD-I system error decoding

🔹 Methods for reading codes without a scanner (by Check Engine blinking)

🔹 Causes of malfunctions and methods for their elimination

🔹 Diagnostic schemes and repair recommendations

💡 Important! OBD-1 does not require a standard OBD-II scanner - codes are read via the on-board computer by blinking the Check Engine lamp.

• Subaru List of Diagnostic Trouble Code (DTC) OBD-II>>

Subaru self-diagnosis by OBD-1. Green connector, black connector.

For more than ten years in a row, the Subaru automobile company has not changed either the location of the diagnostic connectors or the principles of self-diagnosis.

To perform self-diagnosis, you should remove the false panel under the steering column and (preferably with a "carrier"!) carefully examine the "thickest" wiring harness between the steering column and the brake pedal.

If self-diagnosis has never been performed on the car, then upon careful examination we will see connectors tied to the harness - two black and two green:

The connectors are single-contact and seem to "just hang" in the air. By these signs alone, you can fairly accurately determine that these are they - self-diagnosis connectors.

To perform self-diagnosis, connect the two green connectors together (the two black connectors remain unconnected), then turn on the ignition and read the fault code from the blinking "CHECK" light:

11 Crankshaft position sensor

12 Starter switch ("incorrect" signal from the ignition switch)

13 Camshaft position sensor

14 Injector #1 (first cylinder) malfunction — from here on: with this malfunction, the computer diagnoses only an open or short circuit in the circuit. "Stuck" injector needle, "clogged" injector filter and similar problems are not diagnosed or detected by the computer.

15 Injector #2 (second cylinder) malfunction

16 Injector #3 (third cylinder) malfunction

17 Injector #4 (fourth cylinder) malfunction

21 Engine coolant temperature sensor

22 Knock sensor

23 Air Flow sensor …unfortunately, the sensor "out of parameters" is not detected. If necessary, you can replace this sensor with the same one from Nissan - it fits "one to one".

24 Idle speed control unit (valve)

31 Throttle position sensor

32 Oxygen sensor

33 Vehicle speed sensor - see speed sensor malfunction

35 Fuel vapor recovery system (fuel vapor canister valve)

41 The computer has detected that the fuel mixture supplied to the engine cylinders does not correspond to the norm (14.7:1)

42 Idle speed sensor (contact) - closing and opening of the idle speed contact in the throttle position sensor does not correspond to the required parameters (faulty, out of adjustment). The associated malfunction is, for example, increased fuel consumption

49 Air flow sensor

Clearing fault codes from the memory is done by short-circuiting two green and two black diagnostic connectors and then performing a test drive.

In the normal state, both diagnostic connectors are open and the system operates in U-type mode.

Testing Methodology

1. Testing in U-type mode. In U-type mode, the system is constantly: both connectors are disconnected. When the ignition is turned on, the CHECK ENGINE light on the instrument panel lights up briefly and then goes out. This indicates that the diagnostic system is working properly, is in U-type mode and is ready to start the engine. In this mode, the system constantly monitors the operation of the sensors and, if critical errors occur, lights the CHECK ENGINE light when the engine is already running. If this light flashes briefly and goes out, then the errors that have occurred in the system are not so significant and / or short-lived. If the light comes on and remains on constantly, then something serious has happened and you need to stop immediately, turn off the engine and read the error codes. In this mode, only the most important components necessary for starting and operating your car are diagnosed.

2. Using the memory reading mode. To activate the memory reading mode, connect only the black connector (the green connector remains open). In this mode, the system returns the errors accumulated in the controller's memory by flashing the CHECK ENGINE lamp. The black connector should only be connected when the ignition is off! If the lamp flashes continuously and evenly when the ignition is turned on (do not start the engine!), then the diagnostic system has not detected any errors during vehicle operation. If the flashing is uneven, then the error code (one or more with pauses) can be determined by the pulse duration. "Long flashing" - tens in the code, "short" - ones. For example, 3 long, one short - code 31. After that, you can look up the code values for your vehicle in the corresponding table. As a rule, this mode is used after the CHECK ENGINE appears during operation to read "historical" codes, when diagnosing electrical connections and in some other cases when starting the engine is impossible.

3. Testing in D-type mode. For dynamic diagnostics in D-type mode, only the green connector is connected, while the black one is in the open state. The system starts dynamic diagnostics and displays the current errors detected during testing through the CHECK ENGINE lamp. This mode is an extended version of the memory reading mode and is used to diagnose all systems, in the case when the engine can be started. The CHECK ENGINE lamp works the same as when reading memory, but testing is performed on a running and warmed-up engine.

Procedure for using the D-type mode:

3.1. Start the engine and warm it up to operating temperature (about 80 degrees);

3.2. Then turn off the ignition and connect the green connector (Test Mode Connector);

3.3. Turn on the ignition and start the engine (the CHECK ENGINE light is on!);

3.4. Press the gas pedal all the way (the throttle valve is fully open);

3.5. Release the gas pedal halfway for two to three seconds;

3.6. Release the gas pedal completely;

3.7. If the car is equipped with an automatic transmission, you can try to turn on/off all its modes one by one (ECON, POWER, MANU, HOLD, etc.);

3.8. Press the gas pedal, set the mode to about 2000 rpm and hold it for at least a minute. If during the above procedures the CHECK ENGINE lamp lights constantly, then turn off the engine and disconnect the connector - no faults found! If the CHECK ENGINE lamp starts to display codes, then faults have been detected, and the code values can be viewed in the same table as when reading the memory.

4. Using the memory erase mode. In the memory erase mode, both connectors are used: both the green and black connectors are connected. In this mode, the system clears the memory of information about errors accumulated during the operation/testing of the car. As a rule, this mode is used only when all detected faults have been identified and eliminated. When the ignition is turned on and the engine is started, the CHECK ENGINE lamp signals the end of the memory reset of the control system controller by uniformly blinking.

Clear Memory mode usage procedure:

4.1. Start the engine and warm it up to operating temperature (about 80 degrees);

4.2. Then turn off the ignition and connect both the green connector and the black connector;

4.3. Turn on the ignition and start the engine (the CHECK ENGINE light is on!);

4.4. Press the gas pedal all the way down (the throttle valve is fully open);

4.5. Release the gas pedal halfway for two to three seconds;

4.6. Release the gas pedal completely;

4.7. Press the gas pedal, set the mode to about 2000 rpm and hold it for at least a minute. If the CHECK ENGINE light starts flashing evenly about a minute after setting the mode, then the memory clearing has been successfully completed. Turn off the ignition and disconnect the connectors. If the CHECK ENGINE light starts to display codes, then the faults have not been corrected and it is necessary to search for and correct the faults again.

Code 11 (one long flash, one short flash) Crankshaft angle sensor or circuit No cause

Code 12 (one long flash, two short flashes) Starter switch Starter switch stays on or off

Code 13 (one long flash, three short flashes) Camshaft angle sensor No cause

Code 14 (one long flash, four short flashes) Fuel injector 1 Fuel injector erratic

Code 15 (one long flash, five short flashes) Fuel Injector 2 Fuel injector erratic

Code 16 (one long flash, six short flashes) Fuel Injector 3 Fuel injector erratic

Code 17 (one long flash, seven short flashes) Fuel Injector 4 Fuel injector erratic

Code 21 (two long flashes, one short flash) Coolant Temperature Sensor Sensor or sensor circuit malfunctioning

Code 22 (two long flashes, two short flashes) Knock Sensor Sensor circuit open or shorted

Code 23 (two long flashes, three short flashes) Air Flow Sensor Sensor circuit open or shorted

Code 24 (two long flashes, four short flashes) Air Control Valve Valve circuit open or shorted

Code 31 (three long flashes, one short flash) Sensor Throttle Position Sensor Open or shorted circuit

Code 32 (three long flashes, two short flashes) Oxygen Sensor Open circuit in oxygen sensor

Code 33 (three long flashes, three short flashes) Vehicle Speed Sensor No signal from vehicle speed sensor

Code 35 (three long flashes, five short flashes) Purge Solenoid Valve Purge solenoid valve is constantly on or constantly off

Code 41 (four long flashes, one short flash) Air-Fuel Ratio Not optimal air-fuel ratio

Code 42 (four long flashes, two short flashes) Shift Signal Incorrect shift signal

Code 44 (four long flashes, four short flashes) Throttle Actuator Throttle actuator valve is faulty

Code 45 (four long flashes, five short flashes) Barometric Pressure Sensor Barometric Pressure Sensor is faulty

Code 49 (four long flashes, nine short flashes) Air Flow Sensor Air Flow sensor faulty

Code 51 (five long flashes, one short flash) Neutral switch Neutral switch remains permanently on

Code 51 (five long flashes, one short flash) Starter interlock Interlock switch remains permanently on

Code 52 (five long flashes, two short flashes) Parking switch Parking switch remains permanently on.

Other Diagnostic Guide

Code 11 Crankshaft Position Sensor Circuit Malfunction

Code 12 Starter Switch

Code 13 Crankshaft Position Sensor Circuit Malfunction

Code 14 Cylinder 1 Injector Circuit Malfunction

Code 15 Cylinder 2 Injector Circuit Malfunction

Code 16 Cylinder 3 Injector Circuit Malfunction

Code 17 Cylinder 4 Injector Circuit Malfunction

Code 18 Cylinder 5 Injector Circuit Malfunction

Code 19 Cylinder 6 Injector Circuit Malfunction

Code 21 Coolant Temperature Sensor Circuit Malfunction

Code 22 Knock Sensor Circuit Malfunction

Code 23 MAF/Intake Manifold Absolute Pressure (IMP) Circuit Malfunction pipeline

Code 24 Malfunction in the idle air control valve circuit

Code 26 Malfunction in the intake air temperature sensor circuit

Code 28 Malfunction in the knock sensor 2 circuit

Code 29 Malfunction in the crankshaft position sensor circuit

Code 31 Malfunction in the throttle potentiometer circuit

Code 32 Malfunction in the pre-catalytic oxygen sensor circuit

Code 33 Malfunction in the vehicle speed sensor circuit

Code 35 Malfunction in the charcoal canister purge solenoid circuit

Code 37 Malfunction in the post-catalytic oxygen sensor circuit

Code 38 Malfunction in the engine torque control circuit

Code 41 Malfunctions in the mixture quality control system (oxygen sensor)

Code 42 Closed throttle position switch

Code 43 Power supply circuits

Code 44 Solenoid valve turbocharger control system valve metering solenoid wastegate

Code 45 Turbocharger control system solenoid valve sensor/Barometric pressure measurement line switchover valve

Code 47 Economy mode switch

Code 49 Air flow meter

Code 51 Start enable switch

Code 52 Transmission P position switch

Code 53 Engine immobilizer system failure

Code 54 Intake manifold failure

Code 61 Inlet air valve control solenoid failure

Code 62 Exhoust control solenoid (negative pressure)

Code 63 Relief solenoid 1

Code 64 Relief solenoid 2

65 Malfunction in the differential pressure sensor circuit

Code 66 Violations of the twin-turbo scheme operating algorithm

Code 68 Malfunction in the control circuit of the metering solenoid (duty solenoid) of the 2nd turbocharger exhaust gas flow control valve

Code 85 Malfunction of the charging system

Code 87 Variable inlet solenoid - malfunction of the solenoid controlling the valve that changes the geometry of the intake manifold

Code 89 AVSC is out of order

Code 91 TCS relief valve solenoid - malfunction of the solenoid of the anti-skid control system