Normal Operation

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

The PCM uses the Crankshaft Position (CKP) sensor to measure the engine rpm. The PCM sends the Instrument Panel Cluster (IPC) the data over the High Speed Controller Area Network (HS-CAN) communication bus, to command the tachometer gauge according to the data.

The non-hybrid and hybrid tachometers appear differently but function essentially the same. The non-hybrid gauge is an analog gauge with a needle that points to a specified area of the gauge depending on the data received from the PCM. The hybrid gauge is a digital display that provides a bar, which indicates engine rpm when the gas engine is running. When the vehicle transitions into electric vehicle mode, the EV gauge replaces the tachometer. The hybrid tachometer is only displayed in the enlighten display mode.

If the engine rpm data is invalid for 5 seconds or less or if the IPC does not receive the engine rpm data for 5 seconds or less, the IPC defaults the tachometer to the last setting, based upon the last known good rpm message. If the IPC does not receive the engine rpm data from the PCM for more than 5 seconds, the IPC sets DTC U0100:00 in continuous memory and defaults the tachometer to 0 rpm. If the engine rpm data is deemed invalid by the IPC for 5 seconds or more, the IPC sets DTC U0401:68 and defaults the tachometer to 0 rpm.

NOTE: If DTC U0100:00 is set in the IPC , other observable symptoms may be an inoperative speedometer, temperature gauge or odometer.

This pinpoint test is intended to diagnose the following: