Multiplex Communication System - Diagnostics: Diagnosis Toyota 4Runner IV

HOW TO PROCEED WITH TROUBLESHOOTING

Troubleshoot in accordance with the following procedures.

1. VEHICLE BROUGHT TO WORKSHOP
2. CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK (See «PROBLEM SYMPTOMS TABLE»(ref-190100-S38163467752005091300000) )
3. INSPECT COMMUNICATION FUNCTION OF LARGE-SCALE MULTIPLEX COMMUNICATION SYSTEM (BEAN) Check that there is no abnormality in the communication system by inspecting the communication function of the multiplex communication system. (ECU communication stop, communication line abnormal) With code outputs, proceed to A. (ECU communication stop, communication line abnormal) Without code outputs, proceed to B. A : Go to Next Step B : Go To Section Of Each System
4. DIAGNOSTIC TROUBLE CODE CHECK (See «DIAGNOSTIC TROUBLE CODE CHART»(ref-190100-S03041911442005091300000) ) Check for DTCs and make a note of the code that is output. Delete the DTC. Check if the DTC will be output once again, when the problem symptom is simulated based on the noted code. When no code is output (symptom check and simulation is possible), proceed to A. When a code is output, proceed to B. A : Go To Next Step B : Go to step 7
5. «PROBLEM SYMPTOMS TABLE»(ref-190100-S38163467752005091300000) (See ) Without applicable symptoms, proceed to A. With applicable symptoms, proceed to B. A : Go To Next Step B : Go to step 7
6. PERFORM TROUBLESHOOTING IN FOLLOWING METHOD, DEPENDING ON MALFUNCTION SYMPTOM See «PRE-CHECK»(ref-190100-S16138857512005091300000) See «TERMINALS OF ECU»(ref-190100-S18911255862005091300000)
7. ADJUST, REPAIR OR REPLACE END

DIAGNOSTIC TROUBLE CODE CHART

If a malfunction code is displayed during the DTC check, check the circuit listed for that code in the chart below (Proceed to the given for that circuit).

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DIAGNOSTIC TROUBLE CODES (DTC) LIST

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1. CHECK DRIVER SIDE JUNCTION BLOCK ASSY (BODY ECU) Disconnect the IB, IE, IF, IH and IL J/B connectors. Check the voltage or continuity of each terminal of the wire harness side connectors. Standard: If the result is not as specified, there may be a malfunction on the wire harness side.
2. CHECK THEFT WARNING ECU ASSY (THEFT DETERRENT ECU) Disconnect the T5 ECU connector. Check the voltage or continuity of each terminal of the wire harness side connector. Standard: If the result is not as specified, there may be a malfunction on the wire harness side.
3. CHECK MULTIPLEX NETWORK DOOR ECU BACK (BACK DOOR ECU) Disconnect the B8 ECU connector. Check the voltage or continuity of each terminal of the wire harness side connector. Standard: If the result is not as specified, there may be a malfunction on the wire harness side.

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1. TROUBLESHOOTING FOR EACH PROBLEM SYMPTOM NOTE: Confirm the problem symptom and make an inspection depending on the applicable flowchart.

CIRCUIT DESCRIPTION

B1214 and B1215 are output when +B and the body ground is short-circuited on the communication bus. Detecting this condition disables all the BEAN communication and outputs some DTCs.

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1. CHECK DIAGNOSTIC TROUBLE CODE (A ECU) NOTE: Disconnect the connectors in the operational sequence, and start the next Step after the connector is connected. NOTE: In this case, the A ECU represents the back door ECU. Check whether the output of the DTC stops when the A ECU connector is disconnected. Standard: When the output of the DTC stops, the disconnected A ECU is abnormal. OK : Replace A ECU NG : Go To Next Step
2. CHECK DIAGNOSTIC TROUBLE CODE (B ECU) NOTE: Disconnect the connectors in the operational sequence, and start the next step after the connector is connected. NOTE: In this case, the B ECU represents the theft deterrent ECU. Check whether the output of the DTC stops when the B ECU connector is disconnected. Standard: When the output of the DTC stops, the disconnected B ECU is abnormal. OK : Replace B ECU NG : Go To Next Step
3. CHECK WIRE HARNESS BETWEEN BODY ECU AND A ECU OR B ECU Disconnect the A ECU, B ECU and body ECU connectors. Check the wire harness (MPX line) between the A ECU, B ECU and body ECU. Turn the ignition switch ON. Check the voltage between the wire harness (MPX lines) and body ground. Standard: If the output voltage is not 0 V, the wire harness (MPX line) may be short-circuited with +B. Check the continuity of the wire harness (MPX lines) and body ground. Standard: If there is continuity, the wire harness (MPX line) and body ground may be short-circuited with the body ground. OK : Replace Instrument Panel Junction Block Assy NG : Repair Or Replace Wire Harness Between Body ECU And A ECU Or B ECU

DTC B1269 is output when the communication between the theft deterrent ECU and the body ECU stops for more than 10 seconds.

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1. CHECK CONTINUITY OF COMMUNICATION LINE Check the wire harness between the body ECU and theft deterrent ECU. Disconnect the B6 ECU and T5 ECU connectors. Check the continuity between wire harness side connector. Standard: NG : REPAIR OR REPLACE HARNESS AND CONNECTOR OK : Go To Next Step
2. CHECK THEFT WARNING ECU ASSY (THEFT DETERRENT ECU) (POWER SOURCE) Disconnect the T5 ECU connector. Check the voltage between the wire harness side connector and body ground. Standard: NG : REPAIR OR REPLACE HARNESS AND CONNECTOR OK : Go To Next Step
3. CHECK THEFT WARNING ECU ASSY (THEFT DETERRENT ECU) (GROUND) Disconnect the T5 ECU connector. Check the continuity between the wire harness side connector and body ground. Standard: OK : Replace Theft Warning ECU Assy NG : Repair Or Replace Harness And Connector

B1287 is output when the communication between the multiplex network door ECU back (back door ECU) and multiplex network body ECU stops for more than 10 seconds.

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1. CHECK CONTINUITY OF COMMUNICATION LINE Check the wire harness between the body ECU and back door ECU. Disconnect the B4 ECU and B8 ECU connectors. Check the continuity between wire harness side connectors. Standard: OK : Go To Next Step NG : Repair Or Replace Harness And Connector
2. CHECK MULTIPLEX NETWORK DOOR ECU BACK (BACK DOOR ECU) (POWER SOURCE) Disconnect the B8 ECU connector. Check the voltage between the wire harness side connector and body ground. Standard: NG : REPAIR OR REPLACE HARNESS AND CONNECTOR OK : Go To Next Step
3. CHECK MULTIPLEX NETWORK DOOR ECU BACK (BACK DOOR ECU) (GROUND) Disconnect the B8 ECU connector. Check the continuity between wire harness side connector and body ground. Standard: OK : Check Multiplex Network Door ECU Back NG : Repair Or Replace Harness And Connector