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Multiplex Control System: Other Nissan Maxima A32

Body, Cab Control Systems 8 illustrations ~1261 words

PIN VOLTAGE CHARTS

Note. Refer to illustration for connector terminal identification. (Scheme 8)- (Scheme 13).

Scheme 8

Scheme 8: PIN VOLTAGE CHARTS
Scheme 8: PIN VOLTAGE CHARTS

Scheme 9

Scheme 9
Scheme 9

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11

Scheme 12

Scheme 12
Scheme 12

Scheme 13

Scheme 13
Scheme 13

BODY CONTROL MODULE (BCM)

The BCM, a master unit of the multiplex control system, has communication and control capabilities. The BCM consists of a microprocessor and memory and communication LSI sections. The BCM processes data signals received from the LCUs, and sends electrical load data signals to each LCU.

Note. The A/C auto amplifier, if equipped, is built into the BCM. BCM connectors are located on the front side of BCM. DO NOT confuse these connectors with A/C auto amplifier connectors, located on rear side of BCM.

LOCAL CONTROL UNIT (LCU)

The LCU is a slave unit of the BCM and has only communication capability. The LCU consists of communication LSI and input/output interface circuits. The LCU uses data signal from BCM to control on/off operation of electrical loads. The LCU also sends a switch signal to BCM to control on/off operation of sleep/wake-up control mode.

SLEEP/WAKE-UP CONTROL MODE

Note. Wake-up control mode can only be diagnosed using Nissan CONSULT.

The sleep/wake-up control mode allows the communication between BCM and LCUs to be turned on and off, as necessary, to prevent unnecessary power consumption. When BCM detects the following conditions, it will shut off communication with all LCUs and activate sleep mode after about 30 seconds: ignition off, electrical loads off and timer off.

Communication with all LCUs will be re-established (system in normal control mode) if BCM detects a wake-up signal from the data line to LCUs or if a key switch "off" signal (ignition turned from on to off) is detected. The BCM will also re-establish communication with all LCUs if it detects an "on" signal from one of the following switches, which are directly connected to BCM.

  1. Key Switch (Key Inserted)
  2. Ignition Switch (ACC Or ON)
  3. Headlight Switch First Detent)
  4. Door Switches (All Doors)
  5. Trunk Lid Lock/Unlock Switch
  6. Trunk Lid Key Cylinder Tamper Switch
  7. Trunk Compartment Light Switch
  8. Engine Hood Switch
  9. Door Unlock Sensors (All Doors)
  10. Door Key Cylinder Tamper Switches (Front Doors)
  11. Door Key Lock/Unlock Switches (Front Doors)

Mode II (Switch Signal Monitor)

In this mode, BCM and LCUs monitor respective switches in LAN system for input signals. Switch input signals are monitored in the following order.

  1. Hood Switch
  2. Trunk Compartment Light Switch
  3. Trunk Lid Key Cylinder Tamper Switch
  4. Trunk Lid Lock/Unlock Switch
  5. Door Switches
  6. Headlight Switch (First Position)
  7. Wiper Switch (INT Function)
  8. Wiper Switch (WASH Function)
  9. Door Switch (Driver's Side)
  10. Door Switch (Passenger's Side)
  11. Seat Belt Switch
  1. To enter on-board diagnostic Mode II, turn ignition off. Set headlight switch and rear window defogger switch to OFF position. Ensure all doors are closed. Set interior light switch in center "O" position.
  2. Turn ignition on and then off. Repeatedly press rear defogger switch to ON position more than 10 times in 10 seconds, and then hold switch in the ON position. Self-diagnostic indicator lights should come on. Turn ignition switch to ON position within 5 seconds after indicator lights come on.
  3. Indicator lights should go off and within one second, system should enter on-board diagnostic Mode II. Operate the switches specified in step 1). Indicator lights will come on and buzzer will sound each time input signal from a switch is detected. (Scheme 14) To exit diagnostic mode, turn ignition off

Scheme 14

Scheme 14
Scheme 14

IVMS Communication Check

  1. This mode checks for proper communication function between BCM and each LCU on the In-Vehicle Multiplexing System (IVMS). To perform IVMS communication check, enter IVMS system diagnostics.
  2. Select IVMS COMM DIAGNOSIS from CONSULT menu. Record any IVMS related fault messages. Perform appropriate DTC test. See the «CONSULT MESSAGE TEST REFERENCE»(ref-32650-S32014151212001101500000) table. Erase fault message(s) from system memory.

Wake-Up Mode Diagnostics

This mode checks if the respective LCUs are appropriately shifted to wake-up mode when conditions call for such action.

CONSULT Message(1) DTC
POWER WINDOW C/U-DR (COMM FAIL)24
POWER WINDOW C/U-DR (NO RESPONSE)25
POWER WINDOW C/U-AS (COMM FAIL)34
POWER WINDOW C/U-AS (NO RESPONSE)35
POWER WINDOW C/U-RR (COMM FAIL)41
POWER WINDOW C/U-RR (NO RESPONSE)42
POWER WINDOW C/U-RL (COMM FAIL)44
POWER WINDOW C/U-RL (NO RESPONSE)45
MULTI-REMOTE (COMM FAIL)54
MULTI-REMOTE (NO RESPONSE)55
2 Or More POWER WINDOW (COMM FAIL)(2) 24, 34, 41
MULTI-REMOTE (COMM FAIL)44 Or 54
2 Or More POWER WINDOW (NO RESPONSE)(3) 25, 35, 42
Or MULTI-REMOTE (NO RESPONSE)45 Or 55
BCM/LCU (COMM FAIL Or(4) 24, 34, 41
COMM FAIL 2)44 & 54
BCM/HARNESS (COMM LINE)(5) 25, 35, 42 45 & 55
Any POWER WINDOW (SLEEP)(6)
Or MULTI-REMOTE (SLEEP)(6)
(1) Perform appropriate DTC test under DIAGNOSTIC TESTS. If PAST COMM FAIL or PAST NO RESPONSE is displayed, erase memory and recheck for DTCs. (2) If a combination of 2 or more (but not all) of these DTCs exist, go to DTCS 24, 34, 41, 44 OR 54 COMMUNICATION FAULT WITH 2 OR MORE CONTROL UNITS. (3) If a combination of 2 or more (but not all) of these DTCs exist, go to DTCS 25, 35, 42, 45 OR 55 NO COMMUNICATION WITH 2 OR MORE CONTROL UNITS. (4) If all of these DTCs are displayed simultaneously, go to DTCS 24, 34, 41, 44 & 54 COMMUNICATION FAULT WITH ALL CONTROL UNITS. (5) If all of these DTCs are displayed simultaneously, go to DTCS 25, 35, 42, 45 & 55 NO COMMUNICATION WITH ALL CONTROL UNITS. (6) Check for malfunctioning LCU or BCM. Repair as necessary.
(1)Perform appropriate DTC test under DIAGNOSTIC TESTS. If PAST COMM FAIL or PAST NO RESPONSE is displayed, erase memory and recheck for DTCs.
(2)If a combination of 2 or more (but not all) of these DTCs exist, go to DTCS 24, 34, 41, 44 OR 54 COMMUNICATION FAULT WITH 2 OR MORE CONTROL UNITS.
(3)If a combination of 2 or more (but not all) of these DTCs exist, go to DTCS 25, 35, 42, 45 OR 55 NO COMMUNICATION WITH 2 OR MORE CONTROL UNITS.
(4)If all of these DTCs are displayed simultaneously, go to DTCS 24, 34, 41, 44 & 54 COMMUNICATION FAULT WITH ALL CONTROL UNITS.
(5)If all of these DTCs are displayed simultaneously, go to DTCS 25, 35, 42, 45 & 55 NO COMMUNICATION WITH ALL CONTROL UNITS.
(6)Check for malfunctioning LCU or BCM. Repair as necessary.

CONSULT MESSAGE TEST REFERENCE

DTCS 24, 34, 41, 44 OR 54: COMM. FAULT W/2 OR MORE CONTROL UNITS

Note. If DTCs 24, 34, 41, 44 and 54 are all displayed by CONSULT, go to DTCS 24, 34, 41, 44 & 54: COMMUNICATION FAULT WITH ALL CONTROL UNITS.

Erase DTCs and recheck for DTCs. If 2 or more of the specified DTCs are retrieved again, replace appropriate LCU(s). If specified DTCs are not retrieved for a second time, fault is intermittent.

DTCS 24, 34, 41, 44 & 54: COMM. FAULT W/ALL CONTROL UNITS

Erase DTCs and recheck for DTCs. If all specified DTCs are retrieved again and CONSULT displays COMM FAIL, replace BCM. If all specified DTCs are retrieved again and CONSULT displays COMM FAIL 2, replace all LCUs. If all specified DTCs are not retrieved for a second time, fault is intermittent.

DTCS 25, 35, 42, 45 OR 55: NO COMM. W/2 OR MORE CONTROL UNITS

Note. If DTCs 25, 35, 42, 45 and 55 are all displayed by CONSULT, go to DTCS 25, 35, 42, 45 & 55: NO COMMUNICATION WITH ALL CONTROL UNITS.

  1. Check Power Supply To Suspect LCU - Check for poor connection at suspect LCU. See «WIRING DIAGRAMS»(ref-32650-S12063338082001101500000). Check power supply circuit to appropriate LCU. See POWER SUPPLY CIRCUIT TEST table. If power supply circuit is okay, go to next step. POWER SUPPLY CIRCUIT TEST Application & Ignition Switch Position Between Terminals No. Specification BCM OFF, ACC & ON 1 & Ground Battery Voltage OFF 25 & Ground About 0 Volts ACC & ON 25 & Ground Battery Voltage OFF & ACC 27 & Ground About 0 Volts ON 27 & Ground Battery Voltage LCU 01 & LCU 02 (OFF, ACC & ON) 13 & Ground Battery Voltage) LCU 03 & LCU 04 (OFF, ACC & ON) 17 & Ground Battery Voltage) LCU 05 (OFF, ACC & ON) 2 & Ground Battery Voltage)
  2. Check For Open Data Circuits - For LCUs 01, 04 and 05, check continuity between terminal No. 1 at LCU harness connector and terminal No. 12 at BCM harness connector. see scheme 12, see scheme 13 and see scheme 14. For LCUs 02 and 03, check continuity between terminal No. 1 at LCU harness connector and terminal No. 11 at BCM harness connector. If continuity does not exist to all LCUs, repair open data circuit between BCM and LCU in question.

DTCS 25, 35, 42, 45 & 55: NO COMM. W/ALL CONTROL UNITS

  1. Check Data Circuit For Short To Ground - Disconnect BCM harness connector and check terminals for corrosion and damage. Check continuity between ground and terminals No. 11 and 12 at BCM harness connector. If continuity does not exist, go to next step. If continuity exists, repair short to ground in data circuit. See «WIRING DIAGRAMS»(ref-32650-S12063338082001101500000).
  2. Check For Open Data Circuits - For LCUs 01, 04 and 05, check continuity between terminal No. 1 at LCU harness connector and terminal No. 12 at BCM harness connector. see scheme 12, see scheme 13 and see scheme 14. For LCUs 02 and 03, check continuity between terminal No. 1 at LCU harness connector and terminal No. 11 at BCM harness connector. If continuity does not exist to all LCUs, repair open data circuit between BCM and LCU in question. If continuity exists, go to next step.
  3. Check For Shorted LCU - Restore harness connection to BCM. Disconnect each LCU harness connector one at a time, and check system operation of other LCUs. If one LCU affects operation of entire system, it can be assumed that it is internally shorted. Replace suspect LCU. Check system operation. If problem still exists, replace BCM and check system operation.
Fig. 15: Multiplex Control System Wiring Diagram
Scheme 15: Multiplex Control System Wiring Diagram

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