Power Gauge

WARNING: This page is about a different car, the 2011 RAM Pickup and 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

The power gauge gives an indication to the vehicle operator of how the Hybrid Electric Vehicle (HEV) is being operated in terms of the electric or gasoline modes and the relative gasoline fuel economy. This gauge is controlled by the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Hybrid Control Processor (HCP) integral to the Traction Power Inverter Module (TPIM) over the Controller Area Network (CAN) data bus.

The power gauge is a stepper motor design unit that receives battery current on the CCN electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or START positions. The cluster is programmed to move the gauge needle back to the low end of the scale after the ignition switch is turned to the OFF position. The CCN electronic circuitry controls the gauge needle position and provides the following features:

Charging Position Message - Each time the cluster receives electronic messages from the HCP indicating that there is electrical energy being generated by the Regenerative Brake System (RBS) and that the high voltage battery of the HEV system is being recharged it positions the gauge needle within the Charging range of the gauge scale. The gauge needle remains within the Charging range until the cluster receives a message from the HCP to reposition the gauge needle, or until the ignition switch turns to the OFF position, whichever occurs first.
Economy Position Message - If the cluster receives electronic messages from the HCP indicating that the vehicle is being operated in the fuel-saving hybrid electrical mode it positions the gauge needle to the appropriate relative position within the Economy range of the gauge scale. The closer the needle moves to the center of the Economy range indicates that the vehicle is achieving more fuel economy through reliance on the electrical mode of operation; while, the further the needle moves to the right of center indicates that the vehicle is achieving less fuel economy through additional reliance on the gasoline mode of operation. The gauge needle remains within the Economy range until the cluster receives a message from the HCP to reposition the gauge needle, or until the ignition switch turns to the OFF position, whichever occurs first.
Power Position Message - Each time the cluster receives electronic messages from the HCP indicating that the vehicle is achieving the least fuel economy through reliance entirely on the gasoline mode of operation it positions the gauge needle to the appropriate relative position within the Power range of the gauge scale. The further the needle moves toward the right end of the scale, the greater the power being demanded from the gasoline engine and the lower the fuel economy being achieved. The gauge needle remains within the Power range until the cluster receives a message from the HCP to reposition the gauge needle, or until the ignition switch turns to the OFF position, whichever occurs first.
Communication Error - If the cluster fails to receive a power gauge message, it holds the gauge needle at the last indication for about three seconds, or until the ignition switch turns to the OFF position, whichever occurs first. After three seconds, the gauge needle returns to the left end of the gauge scale.

The HCP continually monitors the HEV system circuits, sensors and components as well as inputs from the Powertrain Control Module (PCM) to determine the appropriate HEV operating mode and power gauge positioning strategies. The HCP then sends the proper electronic messages to the instrument cluster, also known as the Cab Compartment Node (CCN) to control the power gauge needle position. For further diagnosis of the power gauge or the instrument cluster circuitry that controls the gauge, refer to Diagnosis and Testing .

Use a diagnostic scan tool for proper diagnosis of the HEV systems, the HCP, the PCM, the CCN, the CAN data bus or the electronic communication related to power gauge operation. Refer to the appropriate diagnostic information.