DTC U0401 [BCM]
id0902f5950500
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Description |
Error signal from PCM |
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Detection condition
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• BCM receives the invalid data from the PCM for 5 s or more.
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Possible cause
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• PCM DTC is stored.
• PCM malfunction
• BCM malfunction
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Diagnostic procedure
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Step |
Inspection |
Action |
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1
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VERIFY PCM DTCs
• Retrieve the PCM DTCs using the M-MDS.
• Are any DTCs displayed?
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Yes
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Repair or replace the malfunctioning part according to the applicable DTC troubleshooting.
(See DTC TABLE [MZI-3.7].)
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No
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Go to the next step.
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2
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PERFORM DTC INSPECTION AND VERIFY PCM MALFUNCTION
• Clear the DTC for the BCM using the M-MDS.
(See CLEARING DTC [BCM].)
• Turn the ignition switch to the ON position and wait for 5 s or more.
• Retrieve the BCM DTCs using the M-MDS.
(See DTC INSPECTION [BCM].)
• Is the same DTC displayed?
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Yes
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Replace the PCM, then go to the next step.
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No
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Go to Step 4.
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3
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VERIFY DTC TROUBLESHOOTING COMPLETED
• Clear the DTC for the BCM using the M-MDS.
(See CLEARING DTC [BCM].)
• Turn the ignition switch to the ON position and wait for 5 s or more.
• Retrieve the BCM DTCs using the M-MDS.
(See DTC INSPECTION [BCM].)
• Is the same DTC displayed?
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Yes
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Repeat the inspection from Step 1.
• If the malfunction recurs, replace the BCM.
Go to the next step.
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No
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Go to the next step.
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4
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VERIFY IF OTHER DTCs DISPLAYED
• Are any other DTCs displayed?
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Yes
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Repair or replace the malfunctioning part according to the applicable DTC troubleshooting.
(See DTC TABLE [BCM].)
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No
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DTC troubleshooting completed.
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