Nissan Maxima Service and Repair Manual: DTC/circuit diagnosis

  • U1000 CAN comm circuit
  • Description CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped on a vehicle and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN-H, CAN-L) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only. DTC Logic DTC DETECTION LOGIC Diagnosis Procedure 1.

  • U1010 control unit (CAN)
  • Description Initial diagnosis of AV control unit. DTC Logic DTC DETECTION LOGIC Diagnosis Procedure 1.

  • U1200 AV control unit
  • Description Part name  Description  AV CONTROL UNIT  It is the master unit of the MULTI AV system and it is connected to each control unit by means of communication. It operates each system according to communication signals from the AV control unit. AV control unit includes audio function and vehicle information function. It is connected to ECM and combination meter via CAN communication to obtain necessary information for the vehicle information function. It inputs the automatic brightness ON/OFF signals that are required for the display dimming control. It inputs the signals for driving status recognition (vehicle speed, reverse and parking brake).

  • U1216 AV control unit
  • Description Part name  Description  AV CONTROL UNIT  It is the master unit of the MULTI AV system and it is connected to each control unit by means of communication. It operates each system according to communication signals from the AV control unit. AV control unit includes audio function and vehicle information function. It is connected to ECM and combination meter via CAN communication to obtain necessary information for the vehicle information function. It inputs the automatic brightness ON/OFF signals that are required for the display dimming control. It inputs the signals for driving status recognition (vehicle speed, reverse and parking brake).

  • U121D AV control unit
  • DTC Logic Diagnosis Pro 1.CHECK PLAYBACK OF A DISK (CD) U121E AV CONTROL UNIT DTC Logic Diagnosis Procedure 1.

  • U1227 AV control unit
  • DTC Logic Diagnosis Procedure 1.CHECK PLAYBACK OF A DISK (DVD) U1228 AV CONTROL UNIT DTC Logic DTC DETECTION LOGIC U1229 AV CONTROL UNIT DTC Logic DTC DETECTION LOGIC U122A AV CONTROL UNIT DTC Logic Diagnosis Procedure 1.PERFORM THE SELF-DIAGNOSIS When U122A is detected, write configuration data with "MULTI AV" of CONSULT.

  • U1232 steering angle sensor
  • DTC Logic Diagnosis Procedu 1.

  • U1243 display unit
  • Description Part name  Description  DISPLAY UNIT  Display image is controlled by the serial communication from AV control unit. Inputs the RGB image signal (RGB, RGB area and RGB synchronizing) from AV control unit and the auxiliary image signal from the auxiliary input jacks. Outputs the synchronizing signals (HP and VP) to the AV control unit.  DTC Logic Diagnosis Procedure 1.CHECK DISPLAY UNIT POWER SUPPLY AND GROUND CIRCUIT Check display unit power supply and ground circuit 2.CHECK CONTINUITY OF COMMUNICATION CIRCUIT Turn ignition switch OFF. Disconnect display unit connector and AV control unit connector.

  • U1263 USB
  • DTC Logic Diagnosis Procedure 1.CHECK USB HARNESS Visually check USB harness.

  • U1255 satellite radio tuner
  • Descriptio Part name  Description  SATELLITE RADIO TUNER  Inputs the satellite radio signal from satellite radio antenna and outputs the sound signal to the AV control unit. It is controlled with the AV control unit and serial communication (communication signal and request signal).  DTC Logic Diagnosis Procedure 1.CHECK SATELLITE RADIO TUNER POWER SUPPLY AND GROUND CIRCUIT Check satellite radio tuner power supply and ground circuit 2.CHECK CONTINUITY COMMUNICATION CIRCUIT AND REQUEST SIGNAL CIRCUIT Turn ignition switch OFF. Disconnect AV control unit connector M116 and satellite radio tuner connector B111.

  • U1300 AV comm circuit
  • Description U1300 is indicated when a communication signal malfunction occurs. U1300 is indicated along with DTCs that identify components connected to the AV control unit through communication lines. Determine the possible malfunction cause from the table below.

  • U1310 AV control unit
  • Description Part name  Description  AV CONTROL UNIT  It is the master unit of the MULTI AV system and it is connected to each control unit by means of communication. It operates each system according to communication signals from the AV control unit. AV control unit includes audio function and vehicle information function. It is connected to ECM and combination meter via CAN communication to obtain necessary information for the vehicle information function. It inputs the automatic brightness ON/OFF signals that are required for the display dimming control. It inputs the signals for driving status recognition (vehicle speed, reverse and parking brake).

  • Power supply and ground circuit
  • AV CONTROL UNIT AV CONTROL UNIT : Diagnosis Procedure 1.CHECK FUSES Check that the following fuses of the AV control unit are not blown. 2.POWER SUPPLY CIRCUIT CHECK Disconnect AV control unit connectors M115 and M119. Check voltage between the AV control unit connectors M115 and M119 and ground 3.GROUND CIRCUIT CHECK Turn ignition switch OFF. Check continuity between AV control unit harness connector and ground. DISPLAY UNIT DISPLAY UNIT : Diagnosis Procedure 1.CHECK POWER SUPPLY CIRCUIT Turn ignition switch to ACC. Check voltage between display unit harness connector M141 and ground. 2.CHECK POWER SUPPLY CIRCUIT Turn ignition switch OFF.

  • RGB (R: red) signal circuit
  • Description Transmit the image displayed with AV control unit with RGB signal to the display unit. Diagnosis Procedure 1.CHECK CONTINUITY RGB (R: RED) SIGNAL CIRCUIT Turn ignition switch OFF. Disconnect display unit connector M141 and AV control unit connector M117. Check continuity between display unit harness connector M141 (A) terminal 17 and AV control unit harness connector M117 (B) terminal 40. Check continuity between display unit harness connector M141 (A) terminal 17 and ground. 2.CHECK RGB (R: RED) SIGNAL Connect display unit connector M141 and AV control unit connector M117. Turn ignition switch ON. Check signal between display unit harness connector M141 terminal 17 and ground.

  • RGB (G: green) signal circuit
  • Description Transmit the image displayed with AV control unit with RGB signal to the display unit. Diagnosis Procedure 1.CHECK CONTINUITY RGB (G: GREEN) SIGNAL CIRCUIT Turn ignition switch OFF. Disconnect display unit connector M141 and AV control unit connector M117. Check continuity between display unit harness connector M141 (A) terminal 6 and AV control unit harness connector M117 (B) terminal 39. Check continuity between display unit harness connector M141 (A) terminal 6 and ground. 2.CHECK RGB (G: GREEN) SIGNAL   Connect display unit connector M141 and AV control unit connector M117. Turn ignition switch ON.

  • RGB (B: blue) signal circuit
  • Description Transmit the image displayed with AV control unit with RGB signal to the display unit. Diagnosis Procedure 1.CHECK CONTINUITY RGB (B: BLUE) SIGNAL CIRCUIT Turn ignition switch OFF. Disconnect display unit connector M141 and AV control unit connector M117. Check continuity between display unit harness connector M141 (A) terminal 18 and AV control unit harness connector M117 (B) terminal 38. Check continuity between display unit harness connector M141 (A) terminal 18 and ground. 2.CHECK RGB (B: BLUE) SIGNAL Connect display unit connector M141 and AV control unit connector M117. Turn ignition switch ON. Check signal between display unit harness connector M141 terminal 18 and ground.

  • RGB synchronizing signal circuit
  • Description Transmit the RGB synchronizing signal to the display unit so as to synchronize the RGB image displayed with AV control unit. Diagnosis Procedure 1.CHECK CONTINUITY RGB SYNCHRONIZING SIGNAL CIRCUIT Turn ignition switch OFF. Disconnect display unit connector M141 and AV control unit connector M117. Check continuity between display unit harness connector M141 (A) terminal 19 and AV control unit harness connector M117 (B) terminal 41. Check continuity between display unit harness connector M141 (A) terminal 19 and ground. 2.CHECK RGB SYNCHRONIZING SIGNAL Connect display unit connector M141 and AV control unit connector M117. Turn ignition switch ON.

  • RGB AREA (YS) signal circuit
  • Description Transmits the display area of RGB image displayed by AV control unit with RGB area (YS) signal to display unit. Diagnosis Procedure 1.CHECK CONTINUITY RGB AREA (YS) SIGNAL CIRCUIT Turn ignition switch OFF. Disconnect display unit connector M141 and AV control unit connector M117. Check continuity between display unit harness connector M141 (A) terminal 9 and AV control unit harness connector M117 (B) terminal 43. Check continuity between display unit harness connector M141 (A) terminal 9 and ground. 2.CHECK RGB SYNCHRONIZING SIGNAL Connect display unit connector M141 and AV control unit connector M117. Turn ignition switch ON.

  • Horizontal synchronizing (HP) signal circuit
  • Description In composite image (AUX image, camera image), transmit the vertical synchronizing (VP) signal and horizontal synchronizing (HP) signal from display unit to AV control unit so as to synchronize the RGB images displayed with AV control unit such as the image quality adjusting menu, etc. Diagnosis Procedure 1.CHECK CONTINUITY HORIZONTAL SYNCHRONIZING (HP) SIGNAL CIRCUIT Turn ignition switch OFF. Disconnect display unit connector M141 and AV control unit connector M117. Check continuity between display unit harness connector M141 (A) terminal 8 and AV control unit harness connector M117 (B) terminal 45.

  • Vertical synchronizing (VP) signal circuit
  • Description In composite image (AUX image, camera image), transmit the vertical synchronizing (VP) signal and horizontal synchronizing (HP) signal from display unit to AV control unit so as to synchronize the RGB images displayed with AV control unit, such as the image quality adjusting menu, etc. Diagnosis Procedure 1.CHECK CONTINUITY VERTICAL SYNCHRONIZING (VP) SIGNAL CIRCUIT Turn ignition switch OFF. Disconnect display unit connector M141 and AV control unit connector M117. Check continuity between display unit harness connector M141 (A) terminal 20 and AV control unit harness connector M117 (B) terminal 57.

  • Front door speaker
  • Description The AV control unit sends audio signals to the front door speakers using the front door speaker circuits. Diagnosis Procedure 1.CONNECTOR CHECK Check the AV control unit and speaker connectors for the following: Proper connection Damage Disconnected or loose terminals 2.HARNESS CHECK Disconnect AV control unit connector M115 (A) and suspect speaker connector (B). Check continuity between AV control unit harness connector M115 (A) terminal and suspect speaker harness connector (B) terminal. Check continuity between AV control unit harness connector M115 (A) terminal and ground. 3.FRONT DOOR SPEAKER SIGNAL CHECK Connect AV control unit connector and front speaker connector.

  • Tweeter
  • Description The AV control unit sends audio signals to the tweeters using the front door speaker circuits. Diagnosis Procedure 1.CONNECTOR CHECK Check the AV control unit and speaker connectors for the following: Proper connection Damage Disconnected or loose terminals 2.HARNESS CHECK Disconnect AV control unit connector M115 (A) and suspect tweeter connector (B). Check continuity between AV control unit harness connector M115 (A) and suspect tweeter harness connector (B). Check continuity between AV control unit harness connector M115 (A) and ground. 3.TWEETER SIGNAL CHECK Connect AV control unit connector and tweeter connector. Turn ignition switch to ACC. Push POWER switch.

  • Rear door speaker
  • Description The AV control unit sends audio signals to the rear door speakers using the rear door speaker circuits. Diagnosis Procedure 1.CONNECTOR CHECK Check the AV control unit and speaker connectors for the following: Proper connection Damage Disconnected or loose terminals 2.HARNESS CHECK Disconnect AV control unit connector M115 (A) and suspect speaker connector. Check continuity between AV control unit harness connector M115 (A) and suspect speaker harness connector (B). Check continuity between AV control unit harness connector M115 (A) and ground. 3.REAR DOOR SPEAKER SIGNAL CHECK Connect AV control unit connector and rear door speaker connector. Turn ignition switch to ACC.

  • Subwoofer
  • Description The AV control unit sends audio signals to the subwoofer amp. The subwoofer amp. amplifies the audio signals before sending them to the subwoofers using the audio signal circuits. Diagnosis Procedure 1.CONNECTOR CHECK Check the AV control unit, subwoofer amp. and subwoofer connectors for the following: Proper connection Damage Disconnected or loose terminals 2.HARNESS CHECK Disconnect subwoofer amp. connector B21 and suspect subwoofer connector. Check continuity between subwoofer amp. harness connector B21 (A) and suspect subwoofer harness connector (B). Check continuity between subwoofer harness connector B21 (A) and ground. 3.REAR SUBWOOFER SIGNAL CHECK Connect subwoofer amp.

  • Steering switch
  • Description When one of the steering wheel audio control switches is pushed, the resistance in the steering wheel audio control switch circuit changes, depending on which button is pushed. Diagnosis Procedure 1.CHECK STEERING SWITCH RESISTANCE Disconnect steering switch connector M88. Check resistance between steering switch connector terminals. 2.CHECK HARNESS BETWEEN COMBINATION SWITCH (SPIRAL CABLE) AND AV CONTROL UNIT Disconnect AV control unit connector M115. Check continuity between AV control unit harness connector M115 and combination switch (spiral cable) harness connector M30. Check continuity between AV control unit connector M115 and ground. 3.

  • Communication signal circuit
  • SATELLITE RADIO TUNER SATELLITE RADIO TUNER : Description Communication signals are exchanged between the AV control unit and satellite radio tuner using the communication circuits. SATELLITE RADIO TUNER : Diagnosis Procedure 1.CHECK HARNESS - 1 Turn ignition switch OFF. Disconnect satellite radio tuner (factory installed) connector B111 and AV control unit connector M116. Check continuity between satellite radio tuner (factory installed) harness connector B111 (A) terminal 28 and AV control unit harness connector M116 (B) terminal 28. Check continuity between satellite radio tuner (factory installed) harness connector B111 (A) terminal 28 and ground. 2.

  • Sound signal circuit
  • SATELLITE RADIO TUNER SATELLITE RADIO TUNER : Description Left and right channel audio signals are supplied from the satellite radio tuner to the AV control unit through the sound signal circuits. SATELLITE RADIO TUNER : Diagnosis Procedure LEFT CHANNEL 1.CHECK HARNESS Turn ignition switch OFF. Disconnect satellite radio tuner (factory installed) connector B111 and AV control unit connector M116. Check continuity between satellite radio tuner (factory installed) connector B111 (A) and AV control unit connector M116 (B). Check continuity between satellite radio tuner (factory installed) connector B111 (A) and ground. 2.

  • Microphone signal circuit
  • Description Voice signals are transmitted from the microphone to the Bluetooth control unit using the microphone signal circuits. Diagnosis Procedure 1.CHECK HARNESS BETWEEN BLUETOOTH CONTROL UNIT AND MICROPHONE Turn ignition switch OFF. Disconnect Bluetooth control unit connector and microphone connector. Check continuity between Bluetooth control unit harness connector B131 (A) and microphone harness connector R7 (B). Check continuity between Bluetooth control unit harness connector B131 (A) and ground. 2.CHECK MICROPHONE POWER SUPPLY Connect Bluetooth control unit connector and microphone connector. Turn ignition switch ON.

Diagnosis system (bluetooth control unit)

U1000 CAN comm circuit