I have noticed the check engine light intermittently lighting up. Sometimes in the morning and sometimes while it's warmed up. If there is a problem in the morning the car is a little harder to start like the choke isn't working. Of course it's efi, so that doesn't make sense, but maybe it's the cold start injector or something like that. If it lights up when the car is warm it really doesn't have any power, like it's in limp mode. how can I read the codes, or does someone have ideas on this symptom?

Great reference: http://www.ultimatesubaru.org/forum/topic/47526-subaru-ecu-codes-for-1983-1988/

This still applies to the Loyales

-- 1988 and Later Models With Single-Point Fuel Injection -- 

CODE PROBABLE CAUSE 
11 Crank Angle Sensor or Circuit 
12 Starter Switch or Circuit 
13 Crank Angle Sensor or Circuit 
14 Fuel Injector - Abnormal Output 
21 Coolant Temperature Sensor or Circuit 
23 Air Flow Meter or Circuit 
24 Air Control Valve or Circuit 
31 Throttle Sensor or Circuit 
32 Oxygen Sensor or Circuit 
33 Vehicle Speed Sensor (VSS) or Circuit 
34 EGR Solenoid or Circuit 
35 Purge Control Solenoid or Circuit 
42 Idle Switch or Circuit 
45 Kick-Down (Detent) Relay or Circuit 
51 Neutral Switch Continuously in the On Position 
55 EGR Temperature Sensor or Circuit 
61 Parking Switch or Circuit 

 

I can't recall if you have to connect the test plugs or not with the loyales, I seem to recall my old 90 loyale would show the ECU blinking lights with the key turned on regardless.

And these could be helpful too:
http://www.ultimatesubaru.org/forum/topic/18385-reading-codes-on-94-loyale-edit-92-not-94/
http://www.ultimatesubaru.org/forum/topic/3992-one-more-timehow-do-you-check-ecu-trouble-codes-on-ea82/

Basically you remove the plastic guard under the steering column to view the LED on the ECU. The process of connecting the test cables is listed in the post(s) above.

Edited February 2, 20188 yr by Ibreakstuff

When the code is a tive, you don't need to connect anything. If it's intermittent, the memory connection will show those.

 

Check the CTS. With an ohm meter, and the table in the fsm. It is the 2 wire sensor on the lower thermostat housing.

if its running rough in the AM and hard starting, my guess from experience is the coolant temp sensor is not functioning correctly, (Code 21) therefore not telling the ECM to richen the mixture for a cold start condition (common failure). Hope this helps 

Thank you!