DTC U0401 [BCM]

id0902f5950500

Description | Error signal from PCM
--- | ---
Detection condition | • BCM receives the invalid data from the PCM for 5 s or more.
Possible cause | • PCM DTC is stored. • PCM malfunction • BCM malfunction

Diagnostic procedure

Step | Inspection | Action
--- | --- | ---
1 | VERIFY PCM DTCs • Retrieve the PCM DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) • Are any DTCs displayed? | Yes | Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [MZI-3.7].)
No | Go to the next step.
2 | 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? | Yes | Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [MZI-3.7].)
No | Go to Step 4.
3 | 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? | Yes | Repeat the inspection from Step 1. • If the malfunction recurs, replace the BCM. (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION.) Go to the next step.
No | Go to the next step.
4 | VERIFY IF OTHER DTCs DISPLAYED • Are any other DTCs displayed? | Yes | Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [BCM].)
No | DTC troubleshooting completed.