Engine Self Test 1990-92 2.2L 4-Cylinder Engine w/Manual Transaxle

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Engine Self Test: 1990-92 2.2L 4-Cylinder Engine w/Manual Transaxle

Overview;
The 'Check Engine' light or MIL (Malfunction Indicator Light) light on the instrument cluster illuminates when the ignition is turned to the 'On' position. It will go off a second or two after the engine is started. If the light stays illuminated after the engine is started or illuminates while driving, there may be a problem with the engine. Checking for error codes is an easy way to find out what's wrong and what, if anything, caused the 'Check Engine' light to illuminate. There are two types of self tests. The first is the Key On Engine Off (KOEO) Self Test, which tests the memory and certain sensors for any fault codes. The second test is the Key On Engine Running (KOER) Self Test, which allows you to check for faults present only when the engine is running.


Procedure;
There are three ways to check for error codes:

Engine Code Scanner
If you have a Super STAR II or equivalent engine code scanner, you can perform a quick test on your engine to see if there's anything wrong. Simply connect it according to the manufacturer's instructions and write down the codes that appear. Codes are listed below.

Analog Voltmeter
If you don't have an engine code scanner, you can perform the same test with a standard analog voltmeter. Set the meter to read between 0 and 20 volts. Connect the positive wire of the voltmeter to the light green with black stripe wire on the Self-Test Output (STO) connector. Connect the negative wire to a ground.

Key On Engine Off Self Test: Turn the ignition switch ON, but do not start the engine. When you're ready to start the test, ground the Self-Test Input (STI) connector. It's a red wire with a white stripe located just behind and slightly to the right of the right strut mount (See Image Below).

Key On Engine Running Self Test: Start the engine and allow it to idle. When you're ready to start the test, ground the Self-Test Input (STI) connector. It's a red wire with a white stripe located just behind and slightly to the right of the right strut mount (See Image Below).

The voltmeter will display a pulse for 3 seconds when the test is first started. Engine codes will appear on the display as a pulse. See below for how to interpret the pulses.

MIL Light
If you don't have an engine code scanner, the easiest way to check for error codes is by using the Malfunction Indicator light on the instrument cluster.

Key On Engine Off Self Test: Turn the ignition switch ON, but do not start the engine. When you're ready to start the test, ground the Self-Test Input (STI) connector. It's a red wire with a white stripe located just behind and slightly to the right of the right strut mount (See Image Below).

Key On Engine Running Self Test: Start the engine and allow it to idle. When you're ready to start the test, ground the Self-Test Input (STI) connector. It's a red wire with a white stripe located just behind and slightly to the right of the right strut mount (See Image Below).

The Malfunction Indicator light will go out after a second then will flash the engine error codes, if any. See below for how to interpret the flashes.

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Interpreting the Codes The pulses on the voltmeter and the flashes on the MIL light translate into two digit codes. To simplify things, we'll call all flashes and pulses, pulses. There are two types of pulses. A long pulse is a pulse that lasts 1-1/2 seconds. A short pulse is a pulse that lasts a 1/2 second. These are pretty distinguishable. The long pulse represents the first digit or tens position of the two digit code. The short pulse represents the second digit or ones position of the two digit code. So, if there is one long pulse followed by four short pulses, that would be the number 14. If there isn't any long pulse, the number is less than ten and the first digit is 0. Eight short pulses with no long pulse would be a 08 code. If there is a long pulse, but no short pulse, the code is 10.

Two digit codes are separated by 4 second pause. When all the codes are displayed, the codes will repeat. As an example, eight short pulses, a four second gap, three long pulses, four short pulses, a four second gap, eight short pulses, a four second gap, three long pulses, four short pulses... repeating continuously will be interpreted as two codes 08 and 34.

If there are no codes, then there are no problems found.

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Codes 8 and 34

Clearing the Codes
Disconnect the negative battery cable then pressing on the brake pedal for at least 10 seconds.
Error Codes

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