Circuit Description
The ABS Diagnostic System Check is an organized approach to identifying problems associated with the ABS. This must be the starting point for any ABS related concern and will direct you to the next logical step in diagnosing a malfunction. Most system malfunctions are linked to faulty wiring, connections and occasionally, to components. Understanding the ABS and using the diagnostic tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.
Test Description
The number below refers to the step number on the diagnostic table.
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Lack of communication may be due to a malfunction of the class 2 serial data circuit. The specified procedure determines the particular condition.
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The presence of DTCs that begin with "U" indicates that some other module is not communicating. The specified procedure compiles all of the available information before tests are performed.
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | Go to Scan Tool Does Not Power Up in Data Link Communications | ||||||
Does the scan tool communicate with the control modules listed above? | Go to Step 3 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | |||||||
3 | Select the Display DTCs function on the scan tool for the following control modules.
Does the scan tool display any DTCs? | Go to Step 4 | |||||||
Does the scan tool display any DTCs that begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Step 5 | |||||||
5 | Does the scan tool display DTC P0562, P0563, P0621, P0622, P1637 or P1638? | Go to Diagnostic Trouble Code (DTC) List in Engine Electrical |
