B1242

DTC Code	DTC Name
B1242	Wireless Door Lock Tuner Circuit Malfunction

DESCRIPTION

The door control receiver 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 door control receiver. The door control receiver receives a signal from the electrical key transmitter sub-assembly and sends signals to the main 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).

Note

When replacing or inspecting the door control receiver and wire harness, do not change the position or length of the wire harness. If the wire harness is too close to the door control receiver, entry (w/ Entry Function) and wireless function performance 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.
When replacing the door control receiver, read the transmitter IDs (tire pressure warning system) stored in the old ECU using the GTS and write them down before removal (w/ Tire Pressure Warning System).
It is necessary to perform initialization after registration of the transmitter IDs into the door control receiver if the door control receiver has been replaced (w/ Tire Pressure Warning System).

DTC Code	DTC Detection Condition	Trouble Area
B1242	Short in RDAM to ground between the certification ECU (smart key ECU assembly) and door control receiver. Short in CSEL to ground between the certification ECU (smart key ECU assembly) and door control receiver. Short in RDAM to ground when RCO (5 V) output from the ECU is off.	Harness or connector Door control receiver Certification ECU (smart key ECU assembly)

WIRING DIAGRAM

PROCEDURE

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Text in Illustration
*A	for 12 Pin Type
*B	for 5 Pin Type
*a	Front view of wire harness connector (to Door Control Receiver)

Disconnect the L64*1 or L65*2 receiver connector.

*1: for 5 Pin Type

*2: for 12 Pin Type

Reconnect the E129 ECU connector.

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

Standard Voltage

for 5 Pin Type

Tester Connection	Condition	Specified Condition
L64-4 (+5) - Body ground	Procedure: Engine switch off Electrical key transmitter subassembly brought outside detection area but kept inside wireless function operational area Lock or unlock switch of electrical key transmitter sub-assembly not pressed → pressed	Pulse generation
L64-2 (CSEL) - Body ground	Procedure: Engine switch off All doors closed	Below 1 V → Pulse generation
L64-5 (DATA) - Body ground	Procedure: Engine switch off All doors locked Electrical key transmitter subassembly not inside vehicle Electrical key transmitter subassembly brought outside detection area but kept inside wireless function operational area Lock or unlock switch of electrical key transmitter sub-assembly not pressed → pressed	Pulse generation

Standard Voltage

for 12 Pin Type

Tester Connection	Condition	Specified Condition
L65-8 (+5) - Body ground	Procedure: Engine switch off Electrical key transmitter subassembly brought outside detection area but kept inside wireless function operational area Lock or unlock switch of electrical key transmitter sub-assembly not pressed → pressed	Pulse generation
L65-6 (CSEL) - Body ground	Procedure: Engine switch off All doors closed	Below 1 V → Pulse generation
L65-2 (DATA) - Body ground	Procedure: Engine switch off All doors locked Electrical key transmitter subassembly not inside vehicle Electrical key transmitter subassembly brought outside detection area but kept inside wireless function operational area Lock or unlock switch of electrical key transmitter sub-assembly not pressed → pressed	Pulse generation

Result
Result	Proceed to
OK	A
NG (for 5 Pin Type)	B
NG (for 12 Pin Type)	C

B

REPLACE DOOR CONTROL RECEIVER Click here

C

REPLACE DOOR CONTROL RECEIVER Click here

A

CHECK HARNESS AND CONNECTOR (DOOR CONTROL RECEIVER - CERTIFICATION ECU AND BODY GROUND)

Disconnect the E129 and E130 certification ECU (smart key ECU assembly) connectors.
Disconnect the L64*1 or L65*2 door control receiver connector.

*1: for 5 Pin Type

*2: for 12Pin Type

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

Standard Resistance

for 5 Pin Type

Tester Connection	Condition	Specified Condition
E129-19 (CSEL) - L64-2 (CSEL)	Always	Below 1 Ω
E129-20 (RDAM) - L64-5 (DATA)
E129-18 (RCO) - L64-4 (+5)
E130-11 (E) - Body ground
L64-1 (GND) - Body ground
E129-19 (CSEL) or L64- 2 (CSEL) - Body ground	Always	10 kΩ or higher
E129-20 (RDAM) or L64- 5 (DATA) - Body ground
E129-18 (RCO) or L64-4 (+5) - Body ground

for 12 Pin Type

Tester Connection	Condition	Specified Condition
E129-19 (CSEL) - L65-6 (CSEL)	Always	Below 1 Ω
E129-20 (RDAM) - L65-2 (DATA)
E129-18 (RCO) - L65-8 (+5)
E130-11 (E) - Body ground
L65-12 (GND) - Body ground
E129-19 (CSEL) or L65- 6 (CSEL) - Body ground	Always	10 kΩ or higher
E129-20 (RDAM) or L65- 2 (DATA) - Body ground
E129-18 (RCO) or L65-8 (+5) - Body ground

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

WIRELESS DOOR LOCK CONTROL SYSTEM(w/ Entry and Start System), Diagnostic DTC:B1242