DTC C2121/21 No Signal from Transmitter ID1 in Main Mode; DTC C2122/22 No Signal from Transmitter ID2 in Main Mode; DTC C2123/23 No Signal from Transmitter ID3 in Main Mode; DTC C2124/24 No Signal from Transmitter ID4 in Main Mode; DTC C2125/25 No Signal from Transmitter ID5 in Main Mode; DTC C2181/81 Transmitter ID1 not Received (Test Mode DTC); DTC C2182/82 Transmitter ID2 not Received (Test Mode DTC); DTC C2183/83 Transmitter ID3 not Received (Test Mode DTC); DTC C2184/84 Transmitter ID4 not Received (Test Mode DTC); DTC C2185/85 Transmitter ID5 not Received (Test Mode DTC): Description

The tire pressure warning valve and transmitters that are installed in the tire and wheel assemblies measure the tire pressure of the tires. The measured values are transmitted to the tire pressure warning antenna and receiver on the body as radio waves and then sent to the tire pressure warning ECU. The ECU compares the measured tire pressure values with the tire pressure threshold. When the measured tire pressure value is less than this threshold, the warning light in the combination meter turns on.

The tire pressure warning valve and transmitters constantly send radio waves to the tire pressure warning antenna and receiver.

Under the conditions below, the tire pressure warning antenna and receiver is unable to receive the signals from the tire pressure warning valve and transmitters, and a DTC is stored.

Facilities or devices that use similar radio frequencies are located in the vicinity of the vehicle.
Devices using similar radio frequencies are used in the vehicle.
The ID of the tire pressure warning valve and transmitter is mistyped during registration.
A tire/wheel/transmitter from a different vehicle is installed.
HINT:

DTCs from C2121/21 to C2125/25 can only be cleared by using the Techstream. DTCs from C2181/81 to C2185/85 can be cleared when the transmitter in the tire pressure warning valve and transmitter sends a forced transmission signal or test mode ends. DTCs from C2181/81 to C2185/85 are output only in test mode.

DTC DETECTION CONDITION CHART

DTC Code	DTC Detection Condition	Trouble Area
C2121/21 C2122/22 C2123/23 C2124/24 C2125/25	Following condition (a) or (b) is met: When all conditions below are met: Tire pressure warning valve and transmitter is not in stop mode. Any transmitter ID is not received from tire pressure warning valve and transmitters. For 20 minutes or more, vehicle speed is more than 8 km/h (5 mph) or no vehicle speed signal or engine speed signal is received. When all conditions below are met: Tire pressure warning valve and transmitter is not in stop mode. Transmitter IDs are not received from tire pressure warning valve and transmitters for 20 minutes or more.	Tire pressure warning valve and transmitter Tire pressure warning antenna and receiver Harness or connector Tire pressure warning ECU
C2181/81 C2182/82 C2183/83 C2184/84 C2185/85	Test mode procedure is performed.	Tire pressure warning valve and transmitter Tire pressure warning antenna and receiver Harness or connector Tire pressure warning ECU

NOTE: When DTCs C2121/21 to C2125/25 are set, DTC C2179/79 may be set simultaneously. In such cases, troubleshoot C2179/79 first, then troubleshoot DTCs C2121/21 to C2125/25.

HINT:

It is necessary to perform the procedure to identify the tire pressure warning valve and transmitter that is malfunctioning because it cannot be identified by the output DTC.