Readiness Code
Readiness Code
Information
This service is used to check the status of the diagnostic cycle (readiness), that is to say which emission-related diagnostic functions have been completed by the engine control module (ECM).
US government information (US only)
The United States Environmental Protection Agency (EPA) has issued a guidance letter, "Performing Onboard Diagnostic System checks as Part of a Vehicle Inspection and Maintenance Program" (EPA420-R-01-015 June 2001), that incorporates various implementation issues associated with OBD-I/M testing. One being that the EPA has revised the readiness criteria to allow states to not reject MY 1996-2000 vehicles with two or fewer unset readiness codes, or MY 2001 and newer vehicles with no more than one unset readiness code. As mentioned herein this is suggested practice. Each individual state may abide by this guidance or enforce state regulations suited to their individual environmental needs. Please consult your State Department of Motor Vehicle for your current I/M testing regulations and procedures.
The status will be READY if the engine control module (ECM) has not detected any faults and the diagnostic function has run at least once after diagnostic trouble codes were erased or the engine control module (ECM) was without power.
If the engine control module (ECM) detects a fault, the diagnostic function must run at least twice for the status to be "READY".
If the diagnostic function has not run after diagnostic trouble codes were erased or the engine control module (ECM) was without power, the status will be "NOT READY".
If the diagnostic function has run and the engine control module (ECM) has detected a fault, a diagnostic trouble code will be generated.
Hint: After repair, it may be necessary to check that the vehicle is fault-free by reading out diagnostic trouble codes after all diagnostic functions have run, that is to say check that the engine control module (ECM) has gone through the dignoses without detecting a fault.
For information on test runs, see Verification of repair Verifying Repairs.
Select an alternative to continue:
1. Verify the repair.
2. Read off diagnostic cycle (readiness) status.
1 - Read diagnostic trouble codes.
2 - Diagnostic cycle readout
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Read diagnostic trouble codes.
Hint: If diagnostic trouble codes are stored in the engine control module (ECM), the must be remedied and cleared first. Read out diagnostic trouble codes in VIDA Vehicle Communication, fault trace and remedy stored diagnostic trouble codes.
- Ignition on
- Read off diagnostic trouble codes (DTCs).
There should be no stored diagnostic trouble codes
OK - Erasing diagnostic trouble codes (DTCs)
Not OK - DONE
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Erasing diagnostic trouble codes (DTCs)
Hint: Before test running to verify the repair, the previously stored diagnostic cycle status must be cleared by clearing the diagnostic trouble codes (regardless of whether the codes are stored or not). The status of all diagnostic functions will change to "NOT READY". If the status is "READY" before the test run, it is not possible to determine if the diagnosis ran in the last cycle.
- Ignition on
- Erase diagnostic trouble codes (DTCs).
Numeric Result 0 - Test run
Numeric Result 0 - Test run
Numeric Result 0 - Test run
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Test run
- Ignition ON if there is to be a readout.
Test run the vehicle as described in Verification of repair Verifying Repairs.
Hint: Start the test run with a check of engine temperature and speed. Click the VCT 2000 symbol to read off temperature and speed.
Select Continue.
Continue - Diagnostic cycle readout
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Diagnostic cycle readout
- Ignition off
Note! The ignition must be off to update status parameters. This must be done before the readout.
- Ignition on
- Read off the status of diagnostic functions.
Check that the diagnostic function status is "READY". If the status is "NOT READY", the diagnosis has not run completely.
Other information
- For information on which diagnostic trouble codes are included in diagnostic functions: Verification of repair Verifying Repairs
Is the status of all diagnostic functions "READY"?
Yes - Checking the diagnostic trouble codes (DTCs)
No - Checking the diagnostic trouble codes (DTCs)
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Checking the diagnostic trouble codes (DTCs)
- Ignition on
- Read off diagnostic trouble codes (DTCs).
If the vehicle is fault-free, no diagnostic trouble codes should be stored.
OK - DONE
Not OK - Diagnostic trouble code stored
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Diagnostic trouble code stored
Read out diagnostic trouble codes in VIDA Vehicle Communication, fault trace and remedy stored diagnostic trouble codes.
Select Continue.
Continue - DONE
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Checking the diagnostic trouble codes (DTCs)
Hint: The engine control module (ECM) has not completed diagnostic functions, thus the conditions for diagnosis are not fulfilled. This could be because a diagnostic trouble code is stored in the engine control module (ECM) or the vehicle has not been operated following the operating schedule.
- Ignition on
Read off diagnostic trouble codes (DTCs).
No diagnostic trouble codes should be stored.
OK - Test run
Not OK - Diagnostic trouble code stored
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