Eobdii Diagnosing - LAUNCH TECH CRP 429HD User Manual

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Generally, there are three elements for one J1939 DTC (See Figure 5-7):
• Suspect Parameter Number (SPN) – Indicates what function on the ECU has
failed.
• Failure Mode Indicator (FMI) – Indicates in what way the function failed.
• Occurence (OC) – Indicates the occurence times of the current DTC.
Whereas, if we choose [J1587/1708], the fault code includes:
• Subsystem Identifier (SID) – Indicates what function on the ECU has failed.
• Failure Mode Indicator (FMI) – Indicates in what way the function failed.
• Occurence (OC) – Indicates the occurence times of the current DTC.
*Note: Retrieving and using DTCs for troubleshooting vehicle operation is only one
part of an overall diagnostic strategy. Never replace a part based only on the DTC
definition. Each DTC has a set of testing procedures, instructions and flow charts that
must be followed to confirm the location of the problem. This information can be
found in the vehicle's service manual.
3. Clear diagnostic trouble code
This option allows you to clear the existing or historic trouble codes.
Clearing DTCs does not fix the problem(s) that caused the code(s) to be set. If
proper repairs to correct the problem that caused the code(s) to be set are not
made, the code(s) will appear again and the check engine light will illuminate as
soon as the problem that cause the DTC to set manifests itself.
*Note: After clearing, you should retrieve trouble codes once more or turn ignition
on and retrieve codes again. If there are still some trouble codes in the system,
please troubleshoot the code using a factory diagnosis guide, then clear the code and
recheck.
4. Data stream
This option enables you to read the real-time data stream in character or graphic
form.
*Note: If you must drive the vehicle in order to perform a troubleshooting procedure,
ALWAYS have a second person help you. Trying to drive and operate the CRP 429HD at
the same time is dangerous, and could cause a serious traffic accident.

5.3.2 EOBDII Diagnosing

On Fig. 5-5, tap [EOBD II] to start initializing. Once the initialization is complete,
a screen displaying Monitor Status appears. Tap [OK] to enter the function
selection page.
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CRP 429HD User's Manual