DTC C2121/21: No Signal from Transmitter ID1; DTC C2122/22: No Signal from Transmitter ID2; DTC C2123/23: No Signal from Transmitter ID3; DTC C2124/24: No Signal from Transmitter ID4; 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): Description

The tire pressure warning valve and transmitter installed in each tire and wheel assembly measures the tire pressures. The measured values are transmitted as radio waves to the tire pressure warning antenna and receiver on the body and then sent to the tire pressure warning ECU. The ECU compares the measured air pressure values with the air pressure threshold. When the measured air pressure value is less than this threshold, the warning light in the combination meter comes 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 tire pressure warning valve and transmitter ID is mistyped during registration.
A wheel from a different vehicle is installed.

HINT:

When a transmitter ID is not received from a tire pressure warning valve and transmitter for a total of 20 minutes while the vehicle speed is over 8 km/h (5 mph) or no transmitter ID is received from all of the tire pressure warning valve and transmitters for a total of 20 minutes, DTCs are set.

DTCs from C2121/21 to C2124/24 can only be cleared by using the Techstream. DTCs from C2181/81 to C2184/84 can be cleared when the transmitter in the tire pressure warning valve and transmitter sends a forced transmission signal or signal check mode (test mode) ends. DTCs from C2181/81 to C2184/84 are output only in signal check (test mode).

DTC DETECTION CONDITION CHART

DTC No.	DTC Detection Condition	Trouble Area
C2121/21 C2122/22 C2123/23 C2124/24	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. No transmitter ID is 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 Wire harness or connector Tire pressure warning ECU
C2181/81 C2182/82 C2183/83 C2184/84	Test mode procedure is performed.	Tire pressure warning valve and transmitter Tire pressure warning antenna and receiver Wire harness or connector Tire pressure warning ECU

NOTE: When DTCs C2121/21 to C2124/24 are set, DTC C2173/73 may be set simultaneously. In such cases, troubleshoot C2173/73 first, then troubleshoot DTCs C2121/21 to C2124/24.

HINT:

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