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Tire Pressure Warning (Diagnostic Codes & Circuit Tests): Overview Lexus HS I

Warning System 6 illustrations ~1400 words

DESCRIPTION

The tire pressure warning valve and transmitters installed in the tire and wheel assemblies measure the air pressures 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 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 turns on. The tire pressure warning ECU stores a DTC when the tire pressure warning valve and transmitter stops transmitting signals. At this time, forcibly transmit the signals by releasing the tire pressure rapidly. The stored DTC is cleared when the signal transmission is resumed.

DTC No.DTC Detection ConditionTrouble Area
C2111/11 C2112/12 C2113/13 C2114/14Tire pressure warning valve and transmitters stop transmitting signalsTire pressure warning valve and transmitter Tire pressure warning ECU

HINT

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

Scheme 18

Scheme 18: WIRING DIAGRAM

The tire pressure warning valve and transmitters installed in the tire and wheel assemblies measure the air 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 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 illuminates.

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 valves and transmitters, and a DTC is stored.

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

HINT

These DTCs are detected when no signals are received for 20 minutes or more, after a vehicle speed of 8 km/h (5 mph) or more is detected and no signals are still received for 20 minutes or more.

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 test mode (signal check mode) ends. DTCs from C2181/81 to C2184/84 are output only in test mode (signal check mode).

DTC No.DTC Detection ConditionTrouble Area
C2121/21 C2122/22 C2123/23 C2124/24When both conditions below are met: Tire pressure warning valve and transmitter is not in stop mode When vehicle speed is more than 8 km/h (5 mph), signal is not received from tire pressure warning valve and transmitter for 20 minutes or moreTire pressure warning valve and transmitter Tire pressure warning antenna and receiver Harness or connector Tire pressure warning ECU
C2181/81 C2182/82 C2183/83 C2184/84Test mode (signal check mode) procedure is performed.Tire pressure warning valve and transmitter Tire pressure warning antenna and receiver Harness or connector Tire pressure warning ECU

HINT

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

After all IDs are registered, DTC C2126/26 is set in the tire pressure warning ECU and the tire pressure warning light blinks for 1 minute and then comes on.

When the tire pressure waning ECU successfully receives radio waves from all the transmitters whose IDs are stored in the ECU, DTC C2126/26 is deleted and the tire pressure warning light goes off.

DTC No.DTC Detection ConditionTrouble Area
C2126/26After ID registration is completed, until all tire pressure warning valve and transmitter IDs are received by tire pressure warning ECU.ID registration failure Tire pressure warning valve and transmitter Tire pressure warning antenna and receiver Harness or connector Tire pressure warning ECU

HINT

The purpose of this DTC is to help prevent delivering a vehicle that has incorrectly registered IDs. After all IDs are registered, DTC C2126/26 is detected and the tire pressure warning light blinks for 1 minute and then comes on. If the tire pressure warning light does not turn off after a little while, IDs may be incorrectly registered.

The tire pressure warning valve and transmitters that are installed in the tire and wheel assemblies measure the air 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 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 illuminates.

When the internal circuit of a tire pressure warning valve and transmitter is malfunctioning, one of these DTCs is output.

DTC No.DTC Detection ConditionTrouble Area
C2141/41 C2142/42 C2143/43 C2144/44If an "ERROR" signal is received 3 times consecutively, the tire pressure warning valve and transmitter will be judged as defective and a DTC will be output. This will happen in situations where the inflation pressure is outside the range -100 to 537.5 kPa (-1.0 to 5.4 kgf/cm 2 , -14 psi to 78 psi), the temperature inside the tire is outside the specified range -40 to 120°C (-40 to 253°F), or an error occurs in the tire pressure warning valve and transmitter or the surrounding area.Tire pressure warning valve and transmitter Tire pressure warning ECU

HINT

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

Each tire pressure warning valve and transmitter measures the internal temperature of its tire as well as tire pressure, and transmits the information to the tire pressure warning ECU along with the transmitter ID. If the measured temperature is out of the specified range, the tire pressure warning ECU recognizes it as a malfunction and outputs DTCs, and the tire pressure warning light blinks for 1 minute and then remains on.

DTC No.DTC Detection ConditionTrouble Area
C2165/65 C2166/66 C2167/67 C2168/68Temperature inside the tire exceeds 119°C (246.2°F) more than specified times.Tires Tire pressure warning valve and transmitter Tire pressure warning ECU

HINT

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

The IDs of each tire pressure warning valve and transmitter are registered to the tire pressure warning ECU.

When the ECU detects that an ID is not one of the registered IDs, or cannot receive an ID signal, a DTC is output.

DTC No.DTC Detection ConditionTrouble Area
C2171/71Transmitter ID code is not registered. (When an ID code is unregistered for 3 minutes or more)Tire pressure warning ECU

The signals 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.

DTC No.DTC Detection ConditionTrouble Area
C2176/76Malfunction in the tire pressure warning ECU internal circuit.Tire pressure warning antenna and receiver Harness or connector Tire pressure warning ECU

Scheme 19

Scheme 19: WIRING DIAGRAM

Initialization is necessary if one of the following occurs: 1) before delivery of a new vehicle; 2) after replacement of the tire pressure warning ECU; 3) after replacement of a tire pressure warning valve and transmitter; 4) specified tire pressure changes depending on the size or type of tire; 5) when changing the tire inflation pressure by changing traveling speed or load weight, etc.; or 6) rotating tires that have different specified tire pressures in the front and rear.

DTC No.DTC Detection ConditionTrouble Area
C2177/77When all conditions below are met: During initialization Tire pressure warning valve and transmitter is not in stop mode Signal is not received from tire pressure warning valve and transmitter for 20 minutes or more Vehicle speed is more than 8 km/h (5 mph) for a total of 20 minutesTire pressure warning valve and transmitter Tire pressure warning antenna and receiver Tire pressure warning ECU Harness or connector

The tire pressure warning ECU receives speed signals from the combination meter via CAN communication.

DTC No.DTC Detection ConditionTrouble Area
C2179/79Tire pressure warning ECU communication disruptionCAN communication system Vehicle speed signal circuit Combination meter Tire pressure warning ECU

The tire pressure warning ECU receives speed signals from the combination meter via CAN communication. This DTC is stored upon entering test mode (signal check mode), and cleared when a vehicle speed signal of 20 km/h (12 mph) is detected for 3 seconds or more. This DTC is output only in test mode (signal check mode).

DTC No.DTC Detection ConditionTrouble Area
C2191/91Speed sensor circuit malfunctionCAN communication system Vehicle speed signal circuit Combination meter Tire pressure warning ECU

During initialization, the tire pressure warning ECU receives the signal from the tire pressure warning reset switch. If the ECU receives the signal, the tire pressure warning light blinks 3 times (1 second on, 1 second off).

Scheme 20

Scheme 20: WIRING DIAGRAM

If the ECU detects trouble, the tire pressure warning light blinks (illuminates after blinking for 1 minute) and tire pressure monitor is canceled at the same time. At this time, the ECU records a DTC in the memory.

Connect terminals TC and CG of the DLC3 to make the tire pressure warning light blink and output the DTC.

This is the power source for the tire pressure warning ECU.

Scheme 21

Scheme 21: WIRING DIAGRAM

DTC output mode is set by connecting terminals 13 (TC) and 4 (CG) of the DLC3. The DTCs are indicated by the tire pressure warning light blinking pattern.

Scheme 22

Scheme 22: WIRING DIAGRAM

HINT

If the tire pressure warning light blinks continuously, a ground short in the wiring of terminal TC of the DLC3 or an internal ground short in each ECU is suspected.

Scheme 23

Scheme 23: PROCEDURE
  1. CHECK HARNESS AND CONNECTOR (DLC3 - HYBRID VEHICLE CONTROL ECU AND BODY GROUND) Disconnect the A58 hybrid vehicle control ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F11-13 (TC) - A58-33 (TC) Always Below 1 ohms F11-13 (TC) or A58-33 (TC) - Body ground Always 10 kohms or higher F11-4 (CG) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
  2. INSPECT DLC3 (TC VOLTAGE) Connect the A58 hybrid vehicle control ECU connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition F11-13 (TC) - F11-4 (CG) Power switch on (IG) 11 to 14 V TEXT IN ILLUSTRATION *1 Front view of DLC3 NG --> See step 3 OK --> See step 4
  3. REPLACE HYBRID VEHICLE CONTROL ECU. Refer to «REMOVAL»(ref-398232-S36824664312011051600000)
  4. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-398096-S03342940032011051600000)

See also:
INSPECTION - Step 1