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more than one response message if there are more trouble codes
than will fit in the data bytes of the response message, or if there
are more than one ECU computer responding.
Mode $04 – Used to clear DTCs and Freeze Frame data. This
clears all diagnostic trouble codes that may be set including freeze
frame data and readiness monitors.
Mode $05 – Displays oxygen sensor test results. This mode
displays the oxygen sensor monitor screen and the test results
gathered about the oxygen sensor.
There are ten numbers available for diagnostics:
1. $01 Rich-to-Lean O2 sensor threshold voltage.
2. $02 Lean-to-Rich O2 sensor threshold voltage.
3. $03 Low sensor voltage threshold for switch time measurement.
4. $04 High sensor voltage threshold for switch time measurement.
5. $05 Rich-to-Lean switch time in ms.
6. $06 Lean-to-Rich switch time in ms.
7. $07 Minimum voltage for test.
8. $08 Maximum voltage for test.
9. $09 Time between voltage transitions in ms.
Mode $06 – Non-continuously Monitored Systems test results.
There are typically a minimum value, a maximum value, and a
current value for each non-continuous monitor. This data is
optional, and it is defined by a given vehicle maker if it’s used.
Mode $07 – A request for DTCs (pending) from Continuously
Monitored Systems after a single driving cycle has been performed
to determine if the repair has fixed a problem. This is used by
service technicians to verify repair was performed properly and
after clearing diagnostic trouble codes.
Mode $08 – This special Control Mode requests control of the
on-board system, test, or component bi-directionally (where
applicable). This mode is manufacturer specific.
