1G 1g Code Reader - CEL CODE READER

This is a How-To on figuring out your Check engine light (CEL) for 1g.


Tools:
Volt Meter or LED

Connection:
Connect the positive of the volt meter or LED to pin #1 and the ground to #12 pin on the port.

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After you got that done, turn your key to the ON position and watch the pulse.

A long pulse counts as 10, a short pulse as 1.

1 long pulse: Engine Control Unit Failure ( ECU )
pulses 1 by 1: Normal operation (Heartbeat: on/off repeating)

Codes/pulses:

11. Oxygen Sensor
12. Air Flow Sensor
13. Intake Air Temperature Sensor
14. Throttle Position Sensor
15. Motor Position Sensor
21. Engine Coolant Temperature Sensor
22. Crank Angle Sensor
23. No 1 Top dead center sensor
24. Vehicle Speed Sensor (Reed Switch)
25. Barometric Pressure Sensor
31. Detonation Sensor
36. Ignition Timing Adjustment Signal (1.8L)
41. Fuel Injector
42. Fuel Pump
43. EGR (California) ((This is also a common code when the ecu capacitors have to be replaced.))
44. Ignition Coil ((This is also a common code when the ecu capacitors have to be replaced.))

If you have any questions, Please PM me.

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[steve]

If you use a LED you need a 12v one or a regular LED and a current limiting resistor (For a typical red LED with a 2v forward voltage drop, at 680 ohm 1/4 watt resistor should work).

Pin 1 on the DLC is going to be the positive and pin 12 the ground.

I like using a Radio Shack 12v Piezo Buzzer for the same reason you used the overrange on the DMM, it's easier to count the sound.

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