89-93 models (and later non-turbo/non-OBDII models)
Locate the diagnostic unit behind left strut tower and remove its cover.(see image) Connect selector cable to socket #2,which tests the fuel codes. Turn the ignition switch to the ON position(engine not running). Enter the diagnostic mode by pressing the push button on the diagnostic unit for at least 1 second, but not more than 3 seconds. The red LED light will start to flash,count the number of flashes in 3 flash intervals. The flashes will be seperated by 3 second intervals.Make note of all codes. If no codes are stored,the LED will flash 1-1-1,which means the fuel system is operating correctly.
To access the ignition codes,follow the above procedure,but with the selector cable connected to the #6 socket on the diagnostic unit.
NOTE:Turbocharged models may have seperate codes for the turbo system and are accessse by hooking the selector cable to the #5 socket.
94 and later models with OBDII
The 850 turbo and 960 models are OBD II system which are only accessible with a scanner.
Clearing Trouble Codes
Once all faults have been corrected,turn the ignition switch to the ON position(engine not running).Recheck the codes,then depress the button for 5 seconds and release.After 3 seconds, the LED should light up.While the LED is lit,depress the button again for 5 seconds,when the button is released,the LED should go out.
89-93 models 1-1-1 No faults. 1-1-2 ECU. 1-1-3 Fuel injectors. 1-1-3 Heated Oxygen sensor-max enrichment sensed (94-up). 1-1-5 Injector #1. 1-2-1 Mass airflow sensor. 1-2-2 Air temp sensor signal. 1-2-3 Coolant temp sensor signal. 1-2-5 Injector #2. 1-3-1 Ignition system RPM signal. 1-3-2 Battery voltage. 1-3-3 Throttle switch signal (idle). 1-3-5 Injector #3. 1-4-2 ECU faulty. 1-4-3 Knock Sensor signal missing or defective. 1-4-4 Fuel system load signal(missing or defective). 1-4-5 Injector #4. 1-5-3 Rear heated oxygen sensor signal. 1-5-4 EGR system-leakage or excessive flow. 1-5-5 Injector #5. 2-1-2 Oxygen sensor signal(front sensor on 94 and later models). 2-1-3 Throttle switch signal. 2-1-4 Ignition RPM signal erratic. 2-2-1 Heated Oxygen Sensor(Rich mixture/part throttle). 2-2-2 Main relay. 2-2-3 Idle valve signal. 2-2-4 Coolant temp sensor signal. 2-2-5 A/C pressure sensor signal. 2-3-1 Lambdfa adjustment. 2-3-1 Heated Oxygen sesnor(lean mixture/part throttle) 94-up. 2-3-2 Lamda adjustment. 2-3-2 Adaptive heated O2 sensor control (94-up). 2-3-3 Idle valve-closing signal. 2-3-4 Throttle switch signal missing. 2-4-1 EGR malfunction. 2-4-5 Idle air control valve-closing signal. 3-1-1 Speedometer signal. 3-1-4 Camshaft position signal missing or defective. 3-1-5 EVAP emission control system. 3-2-1 Cold start valve-signal missing. 3-2-2 Airflow meter hot wire. 3-2-4 Camshaft position siganl erratic. 3-2-5 ECU memory failure. 3-3-5 TCM request for MIL. 4-1-1 Throttle switch signal faulty or missing. 4-1-3 EGR temp sensor signal incorrect or missing. 4-1-4 Turbo boost regulation. 4-1-6 Turbo boost reduction from TCM. 4-2-5 Temp warning level #1. 4-3-1 EGR temp sensor faulty or missing. 4-3-2 High temp warning inside ECU. 4-3-3 No rear knock sensor signal. 4-3-5 Front heated oxygen sensor - slow response. 4-3-6 Rear heated oxygen sensor compensation. 4-4-3 Catalytic converter efficiency. 4-4-4 Acceleration sensor signal. 4-5-1 Misfire - #1 cylinder. 4-5-2 Misfire - #2 cylinder. 4-5-3 Misfire - #3 cylinder. 4-5-4 Misfire - #4 cylinder. 4-5-5 Misfire - #5 cylinder. 5-1-1 Adaptive oxygen sensor control-lean mixture at idle. 5-1-2 Oxygen integrator at max lean running limit. 5-1-3 High temp warning inside ECU. 5-1-4 Engine cooling fan-low speed signal faulty. 5-2-1 Oxygen sensor preheating-front. 5-2-2 Oxygen sensor preheating- rear. 5-3-1 Power stage-group A. 5-3-2 Power stage-group B. 5-3-3 Power stage- group C. 5-3-4 Power stage- group C. 5-3-5 TC control valve signal. 5-4-1 EVAP valve signal. 5-4-2 Misfire - more than one cylinder. 5-4-3 Misfire - at least one cylinder. 5-4-4 Misfire - more than one cylinder/catalytic converter damage. 5-4-5 Misfire - at least one cylinder/catalytic converter damage. 5-5-1 Misfire - #1 cylinder/catalytic converter damage. 5-5-2 Misfire - #2 cylinder/catalytic converter damage. 5-5-3 Misfire - #3 cylinder/catalytic converter damage. 5-5-4 Misfire - #4 cylinder/catalytic converter damage. 5-5-5 Misfire - #5 cylinder/catalytic converter damage.