DTC U0028:88 [CONNECTIVITY MASTER UNIT]

2016 – MX-5 – Body and Accessories

Description	Unit communication error (LOCAL-CAN)
Detection condition	The connectivity master unit (CMU) detects CAN bus communication line (LOCAL-CAN) malfunction 10 times continuously.
Fail-safe	Not applicable
Possible cause	Malfunction in CAN bus communication line Connectivity master unit (CMU) malfunction Malfunction in CAN bus communication line
System wiring diagram	Not applicable

Diagnostic Procedure

Step	Inspection		Action
1	VERIFY IF OTHER DTCs DISPLAYED FOR CONNECTIVITY MASTER UNIT (CMU) Clear the DTC for the connectivity master unit (CMU) using the M-MDS. (See CLEARING DTC [CONNECTIVITY MASTER UNIT].) Switch the ignition ON (engine off or on) and wait for 7 s or more. Retrieve the connectivity master unit (CMU) DTCs using the M-MDS. (See DTC INSPECTION [CONNECTIVITY MASTER UNIT].) Is DTC U00184:00 or U0187:00 displayed?	Yes	Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [CONNECTIVITY MASTER UNIT].)
		No	Go to the next step.
2	VERIFY IF MALFUNCTIONING LOCATION IS CONNECTIVITY MASTER UNIT (CMU) DEPENDING ON REPEATABILITY Clear the DTC for the connectivity master unit (CMU) using the M-MDS. (See CLEARING DTC [CONNECTIVITY MASTER UNIT].) Switch the ignition ON (engine off or on) and wait for 7 s or more. Retrieve the connectivity master unit (CMU) DTCs using the M-MDS. (See DTC INSPECTION [CONNECTIVITY MASTER UNIT].) Is the same DTC displayed?	Yes	Replace the connectivity master unit (CMU), then go to the next step. (See CONNECTIVITY MASTER UNIT (CMU) REMOVAL/INSTALLATION.)
		No	Go to the next step.
3	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 [CONNECTIVITY MASTER UNIT].)
		No	DTC troubleshooting completed.