Entering Diagnostic Mode

Turn ignition on. "CHECK ENGINE" lamp should light. Locate diagnostic leads. See Fig 1 . Connect diagnostic terminal leads together. If any trouble codes are stored in ECU memory, the "CHECK ENGINE" lamp will flash 2-digit codes.
The trouble codes will be displayed from lowest to highest numbered code. Each code is repeated three times before the next code sequence is displayed. The trouble codes will be repeated as long as the diagnostic terminals are connected and the ignition is on.

Fig 1: I-TEC Diagnostic Leads & Fuse Location Remove fuse No. 4 to clear memory.

ECU TROUBLE CODE IDENTIFICATION

Code	Problem
12	No Ignition - Normal condition
13	Open Oxygen Sensor Circuit
14	Shorted Coolant Sensor Circuit
15	Incorrect Coolant Sensor Circuit
16	Open Coolant Sensor Circuit
21	Throttle Position Switch Circuits Connected at Same Time
22	Starter Signal Circuit
23	Output Terminal to Ignition Coil Grounded
25	Output Terminal to Vacuum Switching Solenoid Circuit Open or Grounded
33	Open or Shorted Fuel Injector Circuit
35	Ignition Power Transistor Open
41	Bad Signal From Crank Angle Sensor
43	No Idle Position Signal
44	Lean Oxygen Sensor Indication
45	Rich System Indication
51	Faulty ECU
52	Faulty ECU
53	Vacuum Switching Valve
54	Bad Ignition Transistor or Ground
55	Faulty ECU
61	Circuit to Air Flow Sensor Bad
62	Circuit to Air Flow Sensor Bad
63	No Vehicle Speed Sensor Signal
64	Fuel Injector Transistor or Ground
65	Continuous Signal From Throttle Position Switch
66	Open or Shorted Knock Sensor Circuit

Fig 2: Impulse I-TEC System Wiring Diagram