Powertrain Control Module Controlled Tachometer Diagnosis. Chevrolet Impala 2000

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2000 🢒 Impala 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Powertrain Control Module Controlled Tachometer Diagnosis

The PCM controls the pulse frequency in relationship to engine RPM, and sends the information via class II to the Instrument Cluster.

Refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, and Console and Gauges for additional diagnostic information.

Check for the following conditions:

•	Poor connection at the PCM or instrument cluster -- Inspect the harness connectors for the following conditions:

•	Backed out terminals

•	Improper mating

•	Broken locks

•	Improperly formed or damaged terminals

•	Poor terminal to wire connection

•	Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs and Wiring Repairs in Wiring Systems.

•	Damaged harness -- Inspect the wiring harness for damage. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs and Wiring Repairs in Wiring Systems.

Step	Action	Value(s)	Yes	No
1	Did you perform Instrument Cluster Diagnosis performed?	--	Go to Step 2	Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Console and Gauges
2	Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?	--	Go to Step 3	Go to Powertrain On Board Diagnostic (OBD) System Check
3	Are any other DTCs set?	--	Go to Diagnostic Trouble Code (DTC) List/Type	Go to Step 4
4	Install a scan tool. Start the engine. Observe the engine RPM on the scan tool. Does the scan tool RPM match the instrument cluster?	--	Go to Diagnostic Aids	Go to Step 5
5	Verify proper operation of the scan tool. Connect the scan tool to another vehicle and observe the RPM. Does scan tool match vehicle RPM?	--	Go to Tachometer Inaccurate or Inoperative in Instrument Panel, Gauges and Console	Go to Diagnostic Aids