Pinpoint Test H: Incorrect Tachometer Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test H: Incorrect Tachometer Indication
Normal Operation
The PCM uses the Crankshaft Position (CKP) sensor to measure the engine rpm. The PCM sends the Instrument Cluster (IC) the data over the High Speed Controller Area Network (HS-CAN) communication bus to command the tachometer gauge according to the data.
If the IC does not receive the engine rpm data from the PCM for 5 seconds or less, the IC defaults the tachometer to the last setting, based upon the last known good rpm message. If the IC does not receive the engine rpm data from the PCM for more than 5 seconds or if the data received is deemed invalid, the IC sets DTC U0100 in continuous memory and defaults the tachometer to 0 rpm.
NOTE: If DTC U0100 is set in the IC, other observable symptoms may be an inoperative speedometer, temperature gauge (except Hybrid) or odometer.
This pinpoint test is intended to diagnose the following:
- PCM
- IC
PINPOINT TEST H: INCORRECT TACHOMETER INDICATION
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H1 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Check for recorded IC DTCs from the self-test.
- Is DTC U0100 recorded?
Yes
Go To Pinpoint Test AS. Pinpoint Tests AS: DTC U0100
No
GO to H2.
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H2 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 PCM DTCs recorded?
Yes
REFER to Computers and Control Systems Information.
No
GO to H3.
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H3 CARRY OUT THE TACHOMETER ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC tachometer (TACH) active command. Command the tachometer in increments of 10% while monitoring the tachometer. The tachometer indication should increase in increments of approximately 700 rpm (Hybrid) or 800 rpm (except Hybrid) for each 10% change.
- Does the tachometer indication increase within specifications?
Yes
GO to H4.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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H4 CHECK THE ENGINE RPM INPUT USING THE IC DEALER TEST MODE
- Ignition ON.
- Enter Instrument Cluster (IC) Dealer Test Mode.
- NOTE: The display below uses xxx's to represent a numeric or alpha-numeric value. The value may display the same amount of characters represented by the xxx's or there may be more/less depending on the type of display. For example: txxx (base cluster) or TACHOMETER xxx RPM (message center cluster) may display T650 or TACHOMETER 650 RPM.
- Scroll down to txxx (base cluster) or TACHOMETER xxx RPM (message center cluster).
- Start the engine and operate the engine at 1,000, 1,500 and 2,000 rpm while monitoring both the tachometer and the engine rpm input in the dealer test mode.
- Does the engine rpm input agree with the position of the tachometer indication?
Yes
INSTALL a new PCM. TEST the system for normal operation.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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