FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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DTC Test Descriptions


The self-diagnostic tests run to determine if a subsystem has passed or failed a specified test. After a test is performed the PCM/TCM will record test PASS/FAIL criteria for display with a Scan tool. Each code will have three records and are as follows:
- LAST TEST-Indicates whether the diagnostic reported a test passed or failed the last time it ran. (Even if it was not this ignition cycle.) Possible display: PASSED, FAILED, NOT RAN.
- THIS IGNITION-Indicates if diagnostic test has run this ignition cycle and the results of that test(s). Possible display: PASSED, FAILED, PASS & FAIL, NOT RAN.
- SINCE CLEAR: Indicates if diagnostic test has run since DTCs were cleared and the results of that test(s). Possible display: PASSED, FAILED, PASS & FAIL, NOT RAN HISTORY.