ICM (Infotainment Control Module) Fault Tracing (RTJ 16432)

Black or Flashing ICM Display

The audio system in the XC90 is a modular system comprised of several different nodes connected on the MOST (fiber optic) network. The various nodes on the MOST network include: ICM (Infotainment Control Module); MP2 (CD player), MMM (Multi Media Module, this is the Navigation unit); ATM (Antenna Module); AUD (Audio Module); and SUB (Subwoofer). If any  MOST component (including nodes and fiber optic cables) fail to receive and  transmit the proper light signal, MOST lock is not achieved, resulting in a black or flashing ICM display. In order to better diagnose an audio system with black or flashing ICM display, it is critical to identify where the communication fails. The following method describes how to systematically check audio functions:

Check fault codes with VADIS and fault trace accordingly. If the fault is not identified, continue as described below:

• If DTC ICM-DC02 is permanent and display is black, access the ICM MOST connector and verify if light is present by unplugging the C connector from the ICM, pull out the receive cable in terminal C1, (see picture below), reinstall the connector with only the transmit cable installed and verify whether there is light on the receive cable. The signal light should be red in color.
• If there is no light there may be an interrupted cable. In this case, light leaves one node but does not arrive at the next. Use test tool 9512867 (See TNN 39-40) to verify the cable continuity by using the test mode.
• If there is light then use a repeater test tool to bypass one node at a time. If the display functions when a node has been bypassed, the bypassed node should be fault traced according to VADIS.
  NOTE: The ICM cannot be bypassed.

If the fault is not identified by the above method, the audio system must be fault traced. In order to identify the root cause, the system must be fault traced by source.

1. Push the power button twice with a two second pause between and monitor the display for a change.
   1. 1.1. If the display illuminates, continue to step  2 (the problem is not in the ICM itself but in the MOST communication).
   2. 1.2. If there is no change, push the MENU button.
      1. 1.2.1. If the menu is displayed, the problem is not in the ICM, continue to step  2.
      2. 1.2.2. If the menu does not show on the display turn the ignition key to position 0, then back to position II. Press the menu button again.
      3. 1.2.3. If there is no response from the ICM, the ICM should be faulted traced.
2. Push the CD-button and monitor the display for a change.
   1. 2.1. If the CD will play properly, continue to step  3.
   2. 2.2. If the CD will not play properly,
      1. 2.2.1. Try another CD (do not use home burned CDs during fault tracing).
      2. 2.2.2. Continue to step 3.
3. Push the AM/FM button and monitor the display for a change.
   1. 3.1. If AM/FM functions properly, continue to step  4.
   2. 3.2. If AM/FM does not function properly:
      1. 3.2.1. Check functionality in different modes: FM1, FM2, and AM.
4. Fault tracing:
   1. 4.1. No audio in CD mode only: Fault trace the CD player.
   2. 4.2. No audio in AM/FM mode only: Fault trace the ATM (Antenna Module)
   3. 4.3. No audio in both  CD and  AM/FM modes:
      1. 4.3.1. Check MOST lock and display functionality while bypassing nodes as described above.

Note arrows to indicate direction of optical communication.

Receive and transmit cable in ICM connector.

MOST Lock

At start up, the ICM will send out a message to the first MOST node in the ring, normally MP2 (CD player) or MMM (Multi Media Module or Navigation unit), which is assigned number 1 and that node passes the message on to the next one which gets number 2 etc, around the MOST ring.

This happens every time without any needed action. When the ICM eventually receives the returning message it will know how many nodes are on the MOST ring. This is defined as MOST lock and is necessary for continuing function. MOST lock can be read out through VADIS as described below.

Click on the "Information" button for a description about each Parameter.

MOST lock is a direct indication of current MOST ring status, and can be useful if there is an intermittent MOST fault that has not yet triggered the DTC ICM-DC02 or ICM-DC01 codes (DTC ICM-DC02 requires 12 seconds of continuous fault and DTC ICM-DC01 is set due to a fault through the first 30 seconds of key on).

Display Type

Display type indicates if the display is a matrix (graphic) or numeric (standard) display. It is necessary to know which type of display in order to obtain the correct part.

In the above screen, click the "Display type" in the "Parameter, status" window and start reading. This will indicate matrix (graphic) or numeric (standard) display type.

Below is a screen dump of the parts catalogue for Infotainment Control Module (ICM). If the ICM needs to be replaced it is the display (indicated as number 8 below)  that is normally referred to. Since all parts come separately there is no need to order a complete control panel (indicated as number 1 below).

If the ICM does not respond, there is a simple way of verifying display type in the vehicle.

Shine a flashlight on the display in the center console and compare to the pictures below. This first one is the numeric (standard) and the second one is the matrix (graphic).

Numeric (standard)

Matrix (graphic)

Some tips and hints:

• If a CD does not play and the display is black in CD mode but it accepts CD in slot, then it could be a matter of having the wrong HW installed or wrong car configuration. Check the car configuration through Vehicle Communication - CEM, and compare with installed part. To know if it is a CD changer, look for the text "CD-CP" on the sticker or reset power (2 fuses or the connector) to it and listen for the sound when the CD is changing slots. To eject a CD with VADIS the correct command is called "Deck status unload".
• If a node is borrowed from another car, a DTC ICM-6C7x may be set. It must be erased after the correct reload is performed. You can not swap a CD changer (6 disc) with a CD player (1 disc).
• GBL Software is a G  ateway B  oot L  oader that is downloaded to the ICM before a MOST node can download Software. Some times it can happen that you get GBL available then you have to retrieve the GBL to continue. The ICM is downloaded over CAN, and the GBL is only for download to SUB, AUD, MP2, and ATM.
  NOTE: Add Application should be used when installing new hardware on the MOST net. Avoid using the Reload function.
• If the software for a numeric display is downloaded to a matrix display or vice versa the DTC ICM- 1D03 is set.
• After a reload to a MOST node, the OBD cable should be disconnected prior to any further actions (including new software download and starting the vehicle).
• If Ring break diagnostics indicates "poor", this indicates all nodes are communicating, but not properly. In this condition MOST Lock cannot be established. This condition should be fault traced by bypassing nodes, one at a time, with the optical bypass tool (9512867).

List of Terms

• MOST lock/Unlock: See above
• Repeater: A component that receives the optical signal, amplifies the light, then forwards the signal to the next node e.g. Test tool 9512867.
• Ring Break: A way to determine which node does not transmit light. Only one break can be detected at a time.
• Master/Slave: In MOST net, the ICM is master and the other nodes are slaves.
• GBL: Gateway Boot Loader, a help program that ICM uses during a MOST download.
• Allbypass : the node forwards lights (like a jumper), but does not use or send information.