Pinpoint Test I: The Tachometer Is Inoperative
Instrumentation, Message Center and Warning Chimes
Pinpoint Test I: The Tachometer Is Inoperative
Normal Operation
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:
- PCM
- IPC
PINPOINT TEST I: THE TACHOMETER IS INOPERATIVE
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I1 CARRY OUT THE TACHOMETER ACTIVE COMMAND USING THE SCAN TOOL
NOTE: On hybrid vehicles, verify that the IPC display mode is set to the enlighten mode setting before beginning diagnostics.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IPC DataLogger .
- Start the engine.
- NOTE: On hybrid, make sure to set the scan tool to 0 rpm before beginning this test.
- Select the IPC tachometer (TACH_IND) active command. Command the tachometer according to the following table while monitoring the tachometer.
- Does the tachometer start at 0 rpm, move to 3,500 rpm, 7,000 rpm and then return to 0 rpm?
Yes
GO to I2.
No
INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Instrument Panel Cluster (IPC). TEST the system for normal operation.
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I2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST
- Check for recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
- Are any DTCs recorded?
Yes
DIAGNOSE all PCM DTCs first. REFER to Computers and Control Systems Information.
No
GO to I3.
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I3 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST
- Check for recorded DTCs from the IPC self-test.
- Are any DTCs recorded?
Yes
For DTC U0100:00, GO to Pinpoint Test BF. Pinpoint Tests BF: DTC U0100:00
For DTC U0401:68, RETRIEVE and REPAIR all non-network DTCs in the PCM and other modules on the network. REFER to Computers and Control Systems Information and Multifunction Electronic Modules Testing and Inspection for a list of all DTCs.
For all other DTCs, REFER to DTC Charts. Instrumentation, Message Center and Warning Chimes
No
INSTALL a new PCM. TEST the system for normal operation.
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