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Home >> Chevrolet >> 2004 >> Avalanche 2500 >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panel System Displays, Gauges And Console >> Diagnostic Information and Procedures >> DTC P0654: Engine Speed Output Circuit >> Diagnostic Aids

Diagnostic Aids

IMPORTANT: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.

Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid determining how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed.

For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

DTC P0654

Step Action Value(s) Yes No
Schematic Reference:  Instrument Cluster Schematics  
Connector End View Reference:  Instrument Panel, Gages, and Console Connector End Views  ,  Powertrain Control Module (PCM) Connector End Views  , or  Powertrain Control Module (PCM) Connector End Views 
1 Did you perform the Instrument Cluster Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - Instrument Cluster 
2
  1. Start the engine.
  2. Observe the tachometer in the IPC.
Does the tachometer indicate engine RPM?		 - Go Diagnostic Aids Go to Step 3 
3
  1. Turn the ignition OFF.
  2. Disconnect the PCM connector C2.
  3. Turn the ignition ON, with the engine OFF.
  4. Measure the voltage from the engine speed signal circuit to a good ground.
Does the voltage measure greater than the specified value?		 9.5 V Go to Step 4  Go to Step 6 
4 Test the engine speed signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 8  Go to Step 5 
5 Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and repair the condition?		 - Go to Step 8  Go to Step 7 
6 Repair the short to ground in the vehicle speed signal circuit. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 8  -
7
IMPORTANT: Program the replacement PCM.
Replace the PCM. Refer to the following procedures:Did you complete the replacement?		 - Go to Step 8  -
8
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 - Go to Step 2  System OK
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