How to Read ECU Error Codes?
- Warm up the engine, then turn off the ignition.
- Under the steering column, locate two black diagnostic connectors – connect them together.
- Turn the ignition ON (do not start the engine).
- The Check Engine light will begin to flash.
Flash Pattern Interpretation:
- If the light flashes steadily, it means there are no stored errors in the ECU.
- If the light flashes irregularly (like Morse code), it’s transmitting stored fault codes, starting with the most recent.
How to Read a Code:
- Long flashes = tens digit (second digit from the right)
- Short flashes = ones digit (rightmost digit)
- Example:
_ _ … = 2 long + 3 short = code 23
ECU ERROR CODES (Engine Control Unit)
Models from 1989 and later, equipped with multi-point fuel injection.
| Code | Fault Description |
|---|---|
| 11 | Crankshaft position sensor |
| 12 | Starter switch/relay or its circuit |
| 13 | Camshaft position sensor (TDC sensor in Justy) |
| 14 | Injector No. 1 (various models) |
| 15 | Injector No. 2 (various models) |
| 16 | Injector No. 3 (various models) |
| 17 | Injector No. 4 (various models) |
| 18 | Injector No. 5 (SVX) |
| 19 | Injector No. 6 (SVX) |
| 21 | Engine coolant temperature sensor |
| 22 | Knock sensor (right side, SVX) |
| 23 | Mass air flow sensor / Pressure sensor (Justy) |
| 24 | Idle air control valve / Idle solenoid (Justy) |
| 25 | Injectors 3 and 4 (XT6) |
| 26 | Intake air temperature sensor (Justy) |
| 28 | Knock sensor No. 2 (left side, SVX) |
| 29 | Second crankshaft position sensor (SVX) |
| 31 | Throttle position sensor |
| 32 | Oxygen sensor No. 1 (right side, SVX) |
| 33 | Vehicle speed sensor |
| 34 | EGR valve solenoid |
| 35 | Evaporative purge solenoid |
| 36 | Air assist solenoid (Impreza) / Ignition system (Justy) |
| 37 | Oxygen sensor No. 2 (left side, SVX) |
| 38 | Torque control signal (SVX) |
| 41 | Fuel-air mixture controller |
| 42 | Idle switch/relay or its circuit |
| 43 | Throttle switch/relay or its circuit (Justy) |
| 44 | Turbo wastegate control solenoid |
| 45 | Turbo pressure control solenoid / Barometric pressure sensor (NA engines) |
| 49 | Mass air flow sensor |
| 51 | Idle switch (MT) / Brake switch (AT) |
| 52 | Parking brake switch (non-Justy) / Clutch switch (Justy) |
| 55 | EGR system temperature sensor |
| 56 | Exhaust gas recirculation (EGR) system |
| 61 | Parking brake (Loyale) / Fuel tank pressure control solenoid (Impreza) |
| 62 | Fuel temperature sensor (Impreza) / Electrical load signal (Justy) |
| 63 | Fuel tank pressure sensor (Impreza) / Blower switch or its circuit (Justy) |
| 65 | Vacuum sensor |
How to Read ABS Fault Codes
- Locate the diagnostic connector – under the steering column is a double, black, female quick connector (standalone).
Using a jumper wire, connect one pin to ground. - Turn the ignition ON, but do not start the engine.
- The ABS warning light will begin flashing.
- Error codes are read similar to ECU codes (via “dashes and dots”).
- Each stored code is preceded by a start sequence – code 11 (long flash + short flash = dash-dot).
- Each code is separated by this start sequence.
| Code | Fault Description |
|---|---|
| Start Code | |
| 11 | Start code (initiates error code sequence) |
| ABS Sensor Fault – Open circuit or high voltage | |
| 21 | Right front wheel |
| 23 | Left front wheel |
| 25 | Right rear wheel |
| 27 | Left rear wheel |
| ABS Sensor Fault – No signal (short circuit or no pulses) | |
| 22 | Right front wheel |
| 24 | Left front wheel |
| 26 | Right rear wheel |
| 28 | Left rear wheel |
| Solenoid Circuit Faults – Hydraulic Control Unit | |
| 31 | Right front wheel |
| 33 | Left front wheel |
| 39 | Rear wheels |
| Other Faults | |
| 29 | Damaged sensor ring or mechanical fault |
| 41 | ABS control module failure |
| 42 | Low supply voltage |
| 51 | Valve relay fault |
| 52 | Hydraulic motor or motor relay fault |
| 54 | Brake light circuit fault |
| 56 | Incorrect ABS module or G-sensor fault |