Toyota CH-R Service Manual: Wireless Door Lock Tuner Circuit Malfunction (B1242)

Toyota CH-R Service Manual / Door Lock / Wireless Door Lock Control System(w/ Smart Key System) / Wireless Door Lock Tuner Circuit Malfunction (B1242)

DESCRIPTION

The electrical key and TPMS receiver assembly is used to receive radio waves related to the entry functions of the electrical key transmitter sub-assembly. The certification ECU (smart key ECU assembly) decodes the requested electrical key transmitter sub-assembly operation by identifying a key code based on the radio waves received via the electrical key and TPMS receiver assembly. The electrical key and TPMS receiver assembly receives a signal from the electrical key transmitter sub-assembly and sends signals to the main body ECU (multiplex network body ECU) through the certification ECU (smart key ECU assembly). (ex. If a door lock operation is requested, the certification ECU (smart key ECU assembly) sends a door lock command to the main body ECU (multiplex network body ECU)).

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1242

Wireless Door Lock Tuner Circuit Malfunction
  • Short to ground in RDAM terminal circuit between the certification ECU (smart key ECU assembly) and electrical key and TPMS receiver assembly.
  • Short to ground in RDAM terminal circuit when voltage (5 V) is not being output from terminal RCO
  • Wire harness or connector
  • Electrical key and TPMS receiver assembly
  • Certification ECU (smart key ECU assembly)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing or inspecting the electrical key and TPMS receiver assembly and wire harness, do not change the position or length of the wire harness. If the wire harness is too close to the electrical key and TPMS receiver assembly, the performance of the entry function and wireless function may be affected.
  • This DTC is not stored within 10 seconds of the engine switch being turned from on (IG) to off.
  • The wireless door lock control system uses the CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the wireless door lock control system after confirming that the communication system is functioning properly.

    Click here

  • Before replacing the certification ECU (smart key ECU assembly), refer to Registration.

    Click here

  • When replacing the electrical key and TPMS receiver assembly, read the transmitter IDs (tire pressure warning system) stored in the old ECU using the Techstream and write them down before removal.

    Click here

  • It is necessary to perform initialization (Click here ) after registration (Click here ) of the transmitter IDs into the electrical key and TPMS receiver assembly if the electrical key and TPMS receiver assembly has been replaced.

PROCEDURE

1.

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Disconnect the M23 electrical key and TPMS receiver assembly connector.

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

-

-

(b) Measure the voltage and resistance and check for pulses according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

M67-19 (RDAM) - F1-18 (E)

Engine switch off

11 to 14 V

M67-18 (RCO) - F1-18 (E)

always

Below 1 V → 4.5 to 5.5 V pulse generation at regular intervals

Standard Resistance:

Tester Connection

Condition

Specified Condition

F1-18 (E) - Body ground

Always

Below 1 Ω
OK

REPLACE ELECTRICAL KEY AND TPMS RECEIVER ASSEMBLY

NG

2.

CHECK HARNESS AND CONNECTOR (ELECTRICAL KEY AND TPMS RECEIVER ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))

(a) Disconnect the F1 and M67 certification ECU (smart key ECU assembly) connectors.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

M67-19 (RDAM) - M23-2 (DATA)

Always

Below 1 Ω

M67-18 (RCO) - M23-8 (+5)

Always

Below 1 Ω

M23-12 (GND) - Body ground

Always

Below 1 Ω

M23-2 (DATA) or M67-19 (RDAM) - Body ground

Always

10 kΩ or higher

M23-8 (+5) or M67-18 (RCO) - Body ground

Always

10 kΩ or higher
OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
    Diagnostic Trouble Code Chart
    DIAGNOSTIC TROUBLE CODE CHART Wireless Door Lock Control System DTC No. Detection Item Link B1242 Wireless Door Lock Tuner Circuit Malfun ...

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