DTC U0184:00 [CONNECTIVITY MASTER UNIT]

id0902n7055000

Description	Communication error with tuner and amp unit (TAU)
Detection condition	• The connectivity master unit (CMU) cannot receive a CAN signal from the tuner and amp unit (TAU) for 5 s or more.
Fail-safe	Not applicable
Possible cause	• Connectivity master unit (CMU) connector or terminal malfunction • Tuner and amp unit (TAU) connector or terminal malfunction • Short to power supply in wiring harness between connectivity master unit (CMU) terminal 2I and tuner and amp unit (TAU) terminal 1AA • Short to ground in wiring harness between connectivity master unit (CMU) terminal 2J and tuner and amp unit (TAU) terminal 1AB • Short between circuits in the following wiring harness: ? Connectivity master unit (CMU) terminal 2I—Tuner and amp unit (TAU) terminal 1AA ? Connectivity master unit (CMU) terminal 2J—Tuner and amp unit (TAU) terminal 1AB • Open circuit in wiring harness between the following terminals: ? Connectivity master unit (CMU) terminal 2I—Tuner and amp unit (TAU) terminal 1AA ? Connectivity master unit (CMU) terminal 2J—Tuner and amp unit (TAU) terminal 1AB • Open circuit in wiring harness between tuner and amp unit (TAU) terminal 2A and body ground • Tuner and amp unit (TAU) malfunction • Connectivity master unit (CMU) malfunction

Caution

• When disconnecting the connector, verify that there is no looseness, damage, deformation, corrosion, or poor connection of the connector terminals.

Diagnostic Procedure

Step	Inspection		Action
1	INSPECT FOR POWER SUPPLY-RELATED MALFUNCTION • Switch the ignition ON (engine off). • Perform the DTC inspection using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.5T)].) (See DTC INSPECTION [i-ELOOP].) (See DTC INSPECTION [CONNECTIVITY MASTER UNIT].) • Is the power supply-related DTC displayed?	Yes	Note • It may be affected by power supply-related malfunction. Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [PCM (SKYACTIV-G 2.5T)].) (See DTC TABLE [i-ELOOP].) (See DTC TABLE [CONNECTIVITY MASTER UNIT].)
1		No	Go to the next step.
2	INSPECT FOR SHORT TO POWER SUPPLY IN CAN_H SIDE CIRCUIT OF LOCAL-CAN • Measure the voltage between connectivity master unit (CMU) terminal 2I (LOCAL-CAN CAN_H side) and body ground. • Is the voltage B+?	Yes	A short to power supply in CAN_H side circuit of LOCAL-CAN has occurred. • Go to Step 5.
2		No	Go to the next step.
3	INSPECT FOR SHORT TO GROUND IN CAN_L SIDE CIRCUIT OF LOCAL-CAN • Measure the voltage between connectivity master unit (CMU) terminal 2J (LOCAL-CAN CAN_L side) and body ground. • Is the voltage 0 V?	Yes	A short to ground in CAN_L side circuit of LOCAL-CAN has occurred. • Go to Step 6.
3		No	Go to the next step.
4	INSPECT BETWEEN LOCAL-CAN_L AND LOCAL-CAN_H SIDE CIRCUITS FOR SHORT BETWEEN CIRCUITS • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Measure the resistance between connectivity master unit (CMU) 2I and 2J terminals (wiring harness side). • Is the resistance approx. 60 ohms?	Yes	Go to Step 9. (LOCAL-CAN is normal)
4		No	If the resistance is 0 ohm: • A short between circuits has occurred in LOCAL-CAN. ? Go to Step 7. If the resistance is 120 ohms: • An open circuit in the LOCAL-CAN has occurred. ? Go to Step 8.
5	INSPECT WIRING HARNESS FOR SHORT TO POWER SUPPLY • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Disconnect the following connectors: ? Connectivity master unit (CMU) ? Tuner and amp unit (TAU) • Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Switch the ignition ON (engine off or on). • Measure the voltage at the following terminals (wiring harness side). ? Connectivity master unit (CMU) terminal 2I ? Tuner and amp unit (TAU) terminal 1AA • Is the voltage 0 V?	Yes	Go to Step 10.
5		No	Refer to the wiring diagram and verify if there is a common connector between connectivity master unit (CMU) terminal 2I and tuner and amp unit (TAU) terminal 1AA. If there is a common connector: • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which has a short to power supply. Go to Step 11.
6	INSPECT WIRING HARNESS FOR SHORT TO GROUND • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Disconnect the following connectors: ? Connectivity master unit (CMU) ? Tuner and amp unit (TAU) • Inspect for continuity between the following terminals (wiring harness side) and body ground. ? Connectivity master unit (CMU) terminal 2J ? Tuner and amp unit (TAU) terminal 1AB • Is there continuity?	Yes	Refer to the wiring diagram and verify if there is a common connector between connectivity master unit (CMU) terminal 2J and tuner and amp unit (TAU) terminal 1AB. If there is a common connector: • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which has a short to ground. Go to Step 11.
6		No	Go to Step 10.
7	INSPECT WIRING HARNESS FOR SHORT BETWEEN CIRCUITS • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Disconnect the following connectors: ? Connectivity master unit (CMU) ? Tuner and amp unit (TAU) • Inspect between the following terminals (wiring harness side) for continuity. ? Connectivity master unit (CMU) terminals 2I and 2J ? Tuner and amp unit (TAU) terminals 1AA and 1AB • Is there continuity?	Yes	Refer to the wiring diagram and verify if there is a common connector between the following terminals: • Connectivity master unit (CMU) terminal 2I—Tuner and amp unit (TAU) terminal 1AA • Connectivity master unit (CMU) terminal 2J—Tuner and amp unit (TAU) terminal 1AB If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short between circuits to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which has shorted between circuits. Go to Step 11.
7		No	Go to Step 10.
8	INSPECT WIRING HARNESS FOR OPEN CIRCUIT • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Disconnect the following connectors: ? Connectivity master unit (CMU) ? Tuner and amp unit (TAU) • Inspect the wiring harness for continuity between the following terminals (wiring harness side). ? Connectivity master unit (CMU) terminal 2I—Tuner and amp unit (TAU) terminal 1AA ? Connectivity master unit (CMU) terminal 2J—Tuner and amp unit (TAU) terminal 1AB • Is there continuity?	Yes	Refer to the wiring diagram and verify if there is a common connector between the following terminals: • Connectivity master unit (CMU) terminal 2I—Tuner and amp unit (TAU) terminal 1AA • Connectivity master unit (CMU) terminal 2J—Tuner and amp unit (TAU) terminal 1AB If there is a common connector: • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which has an open circuit. Go to Step 11.
8		No	Go to Step 10.
9	INSPECT TUNER AND AMP UNIT (TAU) RELATED-WIRING HARNESS FOR OPEN CIRCUIT • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Disconnect the tuner and amp unit (TAU) connector. • Inspect for continuity between tuner and amp unit (TAU) terminal 2A (wiring harness side) and body ground. • Is there continuity?	Yes	Go to the next step.
9		No	Repair or replace the wiring harness which has an open circuit, then go to Step 11.
10	VERIFY IF MALFUNCTIONING LOCATION IS TUNER AND AMP UNIT (TAU) DEPENDING ON REPEATABILITY • Always reconnect all disconnected connectors. • Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • 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 12 s or more. • Retrieve the connectivity master unit (CMU) DTCs using the M-MDS. (See DTC INSPECTION [CONNECTIVITY MASTER UNIT].)	Yes	Replace the tuner and amp unit (TAU), then go to the next step. (See TUNER AND AMP UNIT (TAU) REMOVAL/INSTALLATION.)
10		No	Go to Step 12.
11	VERIFY THAT REPAIRS HAVE BEEN COMPLETED • Always reconnect all disconnected connectors. • Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • 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 12 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	Repeat the inspection from Step 1. • If the malfunction recurs, replace the connectivity master unit (CMU). (See CONNECTIVITY MASTER UNIT (CMU) REMOVAL/INSTALLATION.) Go to the next step.
11		No	Go to the next step.
12	VERIFY OTHER DTCs DISPLAYED • Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [CONNECTIVITY MASTER UNIT].)
12		No	DTC troubleshooting completed.