B1421

DTC B1421 / B1422 / B1423 / B1424

NOTE:

Each tire pressure sensor is numbered and that number is assigned in the order as its ID code is registered in keyless start control module. It does not indicate tire position (front-left, front-right, rear-left and rear-right). Check what number of tire pressure sensor is assigned to which tire, referring to How to Identify Tire Pressure Sensor Number How to Identify Tire Pressure Sensor Number.

Circuit Diagram










DTC Detecting Condition and Trouble Area






DTC Troubleshooting


1. DTC check
Are DTC B1421, B1422, B1423 and B1424 detected together?
YES
Go to Step 3.
NO
Go to Step 2.
2. Tire pressure sensor check
Determine which tire has tire pressure sensor that detected the DTC, referring to How to Identify Tire Pressure Sensor Number How to Identify Tire Pressure Sensor Number.
Check DTC detected tire pressure sensor for proper operation, referring to Tire Pressure Sensor Inspection Tire Pressure Sensor Inspection.
Is tire pressure sensor working properly?
YES
Replace keyless start control module and recheck DTC. Service and Repair
NO
Replace tire pressure sensor. Tire and/or Tire Pressure Sensor (If Equipped) Mounting and Dismounting
3. Keyless entry / TPMS receiver power supply circuit check
Confirm that ignition mode of keyless push start system is in "OFF".
Disconnect keyless entry / TPMS receiver connector.
Check for proper terminal connection to keyless entry / TPMS receiver connector.
If connections are OK, push engine switch to change ignition mode to "ON".
Check that voltage between "A1" and "C1" circuits is approx. 5 V.
Is it in good condition?
YES
Go to Step 6.
NO
Go to Step 4.
4. Keyless entry / TPMS receiver ground circuit check
Check that voltage between "A1" circuit and ground is approx. 5 V.
Is it in good condition?
YES
Repair or replace keyless entry / TPMS receiver ground circuit.
NO
Go to Step 5.
5. Keyless entry / TPMS receiver power supply circuit check
Push engine switch to change ignition mode to "OFF".
Disconnect "L01" connector.
Check for proper terminal connection to "L01" connector.
If connections are OK, check the following points.
Resistance of "A1" circuit: less than 3
Resistance between "A1" circuit and ground: infinity
Resistance between "A1" circuit terminal and other terminals at keyless entry / TPMS receiver connector: infinity
Voltage of "A1" circuit: 0 - 1 V (with ignition mode of keyless push start system in "ON")
Are they in good condition?
YES
Replace keyless start control module and recheck DTC. Service and Repair
NO
Repair or replace defective wire harness.
6. Keyless entry / TPMS receiver signal circuit check
Push engine switch to change ignition mode to "OFF".
Disconnect "L01" connector.
Check for proper terminal connection to "L01" connector.
If connections are OK, check the following points.
Resistance of "B1" circuit: less than 3
Resistance between "B1" circuit and ground: infinity
Resistance between "B1" circuit terminal and other terminals at keyless entry / TPMS receiver connector: infinity
Voltage of "B1" circuit: 0 - 1 V (with ignition mode of keyless push start system in "ON")
Are they in good condition?
YES
Go to Step 7.
NO
Repair or replace defective wire harness.
7. Keyless entry / TPMS receiver check
Connect connectors to keyless start control module and keyless entry / TPMS receiver.
Check keyless entry / TPMS receiver. Keyless Entry / TPMS Receiver Inspection
Is it in good condition?
YES
Go to Step 8.
NO
Replace keyless entry / TPMS receiver. Keyless Entry / TPMS Receiver Removal and Installation
8. Tire pressure sensor ID code registration
Register tire pressure sensor ID code in keyless start control module. Registration Procedure for Tire Pressure Sensor ID Code
Recheck DTC.
Are DTC B1421, B1422, B1423 and B1424 still detected?
YES
Replace keyless start control module and recheck DTC. Service and Repair
NO
End.