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Home >> Ford >> 2009 >> Flex Limited, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1102 (Instrument Cluster System) >> Diagnostic Tests >> Instrument Cluster (IC) >> Pinpoint Tests >> Pinpoint Test F: Inaccurate Tachometer Indication >> Normal Operation

Normal Operation

WARNING: This page is about a different car, the 2007 Lincoln MKX and 2007 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

The PCM uses the crankshaft position sensor to measure the engine rpm, and sends the instrument cluster the data over the high speed controller area network (HS-CAN) communication bus, to command the tachometer gauge according to the data.

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

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

Possible Causes

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