Manually Reading
ECU Codes for gc8's:
On GC8's faults can be displayed as pulses of the Check Engine Light. (If the Check Engine Light goes out there is no fault)
In order to perform diagnostic (and
ECU resets) you will need to connect some wires together under your steering column. Note, the following procedure is intended for Rs liberty's & Gc8's, it may apply to GD WRX also.
1. Make sure your ignition is OFF
2. Connect the Black ‘Read Memory’ connectors together as illustrated below.
Figure 1 - Black and Green Connectors on GC8
When the above are connected you are in diagnostics mode.
3. Turn your ignition ON and ‘read’ the
ECU code(s) being reported according to the following instructions. Note, you may here relays clicking and your fan starting and stopping - this is normal when in diagnostics mode.
4. If no codes are indicated switch the ignition off and disconnect the diagnostic connectors
In Diagnostic Mode – No Fault is indicated by the Check Engine Light continuously & evenly flashing on/off (this is also used to indicate the successful completion of an
ECU Reset).
The long pulses (1.3 Seconds) indicate Tens and the short pulses (0.2 Seconds) indicate ones. Pulses are separated by Short Pauses (0.2 Seconds), multiple codes are separated by a Long Pause (1.8 Seconds).
The simplest way for an inexperienced mechanic to retrieve codes is to write the codes down in a sort of Morse Code (dots and dashes), and start a new line when you get a 1.8 Second pause (for NEW code), and then add the actual numbers up after code retrieval is completed.
Note – not all error codes are not stored and are not documented (though they are all decoded by a Select Monitor) some of these may be found in the next section.
Code ITEM
11 Crankshaft position sensor
12 Starter switch
13 Camshaft position sensor
21 Engine coolant temperature sensor
22 Knock sensor
23 Mass air flow sensor
24 Idle air control solenoid
31 Throttle position sensor
32 Oxygen sensor
33 Vehicle speed sensor 2
35 Purge control solenoid valve
42 Idle switch
44 Wastegate control solenoid valve
45 Pressure sensor –Pressure exchange solenoid valve
51 Neutral position switch
Other Subaru Codes
These codes are not documented in the Impreza Workshop manual but are mentioned in other Subaru Documentation (and can be decoded by a Select Monitor), these may or may not be applicable to the Impreza.
Code ITEM
11 Crank angle Sensor or Circuit
12 Starter Switch or Circuit
13 Cam Position Sensor or Circuit (TDC Sensor on Justy)
14 Fuel Injector No. 1 (Legacy, Impreza, Justy, SVX)
15 Fuel Injector No. 2 (Legacy, Impreza, Justy, SVX)
16 Fuel Injector No. 3 (Legacy, Impreza, Justy, SVX)
17 Fuel Injector No. 4 (Legacy, Impreza, SVX)
18 Fuel Injector No. 5 (SVX)
19 Fuel Injector No. 6 (SVX)
21 Coolant Temperature Sensor or Circuit
22 Knock Sensor or Circuit (Right Side on SVX)
23 Air Flow Meter or Circuit (Exc. Justy)
24 Air Control Valve or Circuit (Exc. Justy)
25 Fuel injector No. 3 and 4 (XT-6)
26 Air Temperature Sensor (Justy)
28 Knock Sensor No. 2 (SVX, Left Side)
29 Crank Angle Sensor (SVX, No. 2)
31 Throttle Position Sensor or Circuit
32 Oxygen Sensor or Circuit (No. 1, Right Side, On SVX)
33 Vehicle Speed Sensor (VSS) or Circuit
34 EGR Solenoid or Circuit
35 Purge Control Solenoid or Circuit
36 Air Suction Solenoid Valve (Impreza)
37 Oxygen Sensor (No. 2, Left Side, On SVX)
38 Engine Torque Control (SVX)
41 Air/Fuel Adaptive Control
42 Idle Switch or Circuit
43 Throttle Switch
44 Wastegate Duty Solenoid (Turbo Models)
45 Pressure Sensor Duty Solenoid (Turbo Models)
45 Atmospheric Pressure Sensor or Circuit (Non-Turbo Models)
46 Neutral or Parking Switch or Circuit
47 Fuel Injector
49 Airflow Sensor
51 Neutral Switch (Manual Transmission Models)
51 Inhibitor Switch (Automatic Transmission Models)
52 Parking Brake Switch (Exc. Justy)
53 Fuel Pump or Circuit
54 Choke Control System
55 EGR Temperature Sensor or Circuit
56 EGR System
57 Canister Control System
58 Air Control System
61 Fuel Tank Pressure Control Solenoid (Impreza)
62 Fuel Temperature Sensor (Impreza)
63 Fuel Tank Pressure Sensor (Impreza)
64 Vacuum Line Control Valve or Circuit
65 Vacuum Pressure Sensor
66 Sequential turbo system
67 Exhaust valve solenoid (positive pressure)
68 Exhaust valve duty solenoid
71 Ignition Pulse System
73 Ignition Pulse System
74 Ignition Pulse System
88 TBI Control Unit