For 1990-2009 cars

### Instrument Cluster

The instrument cluster receives information via the Class 2 serial data link from the 4 cylinder (L61) Body Control Module (BCM), the powertrain control module (PCM), and the sensing and diagnostic module (SDM). On V6 (L81) engine applications, the information from the engine control module (ECM) and the transaxle control module (TCM) is sent to the BCM over the CAN serial data link where it is converted to a Class 2 message and sent to the cluster. The information from the electronic brake/traction control module (EBTCM) is sent to the BCM, where it is converted into a Class 2 message and sent to the cluster.

### Body Control Module

The body control module (BCM) controls many of the functions of the instrument cluster. The cluster receives commands from the BCM which in turn receives information from other modules as well as from direct wires to components.

### Powertrain Control Module

The powertrain control module (PCM) is used only on the 4 cylinder application, and sends messages to the cluster.

### Sensing and Diagnostic Module

The sensing and diagnostic module (SDM) sends messages to the cluster, with seat belt and SIR system status.

### Speedometer and Tachometer

The input information for the speedometer and tachometer is supplied over the Class 2 serial data link by the powertrain control module (PCM) for the 4 cylinder (L61) engine, and by the Body control module (BCM) on the V6 (L81) engine. The BCM gets the vehicle speed data and engine speed data from the V6 (L81) engine control module (ECM) via the CAN serial data link.

### Odometer

The odometer is an electronic digital display. Digits displayed are illuminated by the odometer backlight bulb. The odometer backlight bulb brightness is controlled by class 2 messages from the BCM to adjust the display for daylight and instrument panel dimming operation. The trip odometer and total odometer will show in this display area. The push button in the lower right side of the speedometer is used to toggle between the trip and total odometer readings. To reset the trip odometer, push and hold the button down for at least two seconds. The total odometer display has six digits with no decimal display. The trip odometer has four digits including a decimal point and indicates tenths of a mile or kilometer.

The body control module (BCM) stores the vehicle mileage. If the BCM fails, the cluster will display the last valid mileage that was sent before the BCM failed. For replacement of the BCM refer to the BCM section of this service manual. Replacement instrument clusters do not require odometer pre-setting before installation. If the instrument cluster is replaced, the mileage stored in the BCM will be sent to the new cluster via serial data, and shown in the odometer display.

### Fuel Gage

The input information for the fuel gauge is sent over the Class 2 serial data link by the body control module (BCM) on V6 (L81) engine appications. Information is sent by the PCM on the 4 cylinder (L61) engine applications to the BCM. The cluster will position the needle on the gauge based on the fuel level information sent by the BCM.