Diagnostic Procedure

DTC U0402:86 [VEHICLE CONTROL MODULE] DIAGNOSTIC PROCEDURE

Step	Inspection	Results	Action
1	INSPECT VEHICLE CONTROL MODULE (VCM) AND BODY CONTROL MODULE (BCM) FOR MALFUNCTION Perform the DTC inspection for the vehicle control module (VCM) and the body control module (BCM). (See DTC INSPECTION .) Is a DTC related to an internal malfunction displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [VEHICLE CONTROL MODULE (US)] .) (See DTC TABLE [BODY CONTROL MODULE (BCM) (US)] .)
1		No	Go to the next step.
2	INSPECT TCM FOR MALFUNCTION Perform the DTC inspection for the TCM. (See DTC INSPECTION .) Is a DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (ET6A-EL ) (US)] .) (See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (EV6A-EL, EV6Ax-EL) (US)] .)
2		No	Go to the next step.
3	INSPECT TCM FOR MALFUNCTION DEPENDING ON REPEATABILITY Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the vehicle control module (VCM). (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW (US) .) If the CAN communication is normal, replace the TCM and perform the repair completion verification. (See CONTROL VALVE BODY REMOVAL/INSTALLATION [ET6A-EL (US)] .) (See CONTROL VALVE BODY REMOVAL/INSTALLATION [EV6A-EL, EV6Ax-EL] .)
3		No	Perform the [ACTION FOR NON-REPEATABLE MALFUNCTIONS]. (See TROUBLESHOOTING PROCEDURE (US) .) If DTC is displayed Repeat the diagnosis from Step 1. If DTC is not displayed Go to repair completion verification 2.
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the vehicle control module (VCM). (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW (US) .) If the CAN communication is normal, perform the diagnosis from Step 1. If the malfunction recurs, replace the body control module (BCM), then go to the next step. (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION .)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTC IS DISPLAYED Perform the DTC inspection. (See DTC INSPECTION .) Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.