code po654
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Pro
Joined: Oct 2005
Posts: 606
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From: Tulsa Oklahoma
code po654
I have had this po654 code for a while. Noone can tell me what to do. I guess there are a million directions I could go with this code. Has anyone else had this code, maybe I could narrow the search. Any help would be greatly appreciated. Thanks.
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From: Saint Augustine, FL
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P0654 Engine RPM Output Circuit Malfunction
Circuit Description
The PCM supplies a voltage to the Engine Speed Output circuit. The PCM creates the Engine Speed Output signal by rapidly grounding this circuit via an internal switch called a driver. The other components on this circuit recognize the voltage being pulled to ground as an indication of engine speed.
The driver supplies the ground for the component being controlled. Each driver has a fault line which the PCM monitors. When the PCM commands a component ON, the voltage of the control circuit should be low (near 0 volts). When the PCM commands the control circuit to a component OFF, the voltage potential of the circuit should be high (near battery voltage). If the fault detection circuit senses a voltage other than what is expected, the fault line status changes causing the DTC to set.
Conditions for Running the DTC
The engine speed is greater than 600 RPM.
Ignition voltage greater than 6.0 volts but less than 16 volts.
Conditions for Setting the DTC
The PCM detects that the commanded state of the driver and the actual state of the control circuit do not match.
All above conditions exist for a minimum of 10.0 seconds.
Action Taken When the DTC Sets
The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails.
The malfunction indicator lamp (MIL) will not illuminate.
The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.
Conditions for Clearing the MIL/DTC
A last test failed, or the current DTC, clears when the diagnostic runs and does not fail.
A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic.
Use a scan tool in order to clear the MIL/DTC.
Diagnostic Aids
Important
Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM\TAC modules.
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 Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Important
If the I/P is completely inoperative, refer to Body and Accessories for further diagnosis.
Further circuit diagnosis may require I/P removal. Check the circuit from the PCM to the tachometer for being open, shorted to ground or, voltage. If you can not find any trouble, follow the appropriate I/P diagnostic procedure.
Circuit Description
The PCM supplies a voltage to the Engine Speed Output circuit. The PCM creates the Engine Speed Output signal by rapidly grounding this circuit via an internal switch called a driver. The other components on this circuit recognize the voltage being pulled to ground as an indication of engine speed.
The driver supplies the ground for the component being controlled. Each driver has a fault line which the PCM monitors. When the PCM commands a component ON, the voltage of the control circuit should be low (near 0 volts). When the PCM commands the control circuit to a component OFF, the voltage potential of the circuit should be high (near battery voltage). If the fault detection circuit senses a voltage other than what is expected, the fault line status changes causing the DTC to set.
Conditions for Running the DTC
The engine speed is greater than 600 RPM.
Ignition voltage greater than 6.0 volts but less than 16 volts.
Conditions for Setting the DTC
The PCM detects that the commanded state of the driver and the actual state of the control circuit do not match.
All above conditions exist for a minimum of 10.0 seconds.
Action Taken When the DTC Sets
The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails.
The malfunction indicator lamp (MIL) will not illuminate.
The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.
Conditions for Clearing the MIL/DTC
A last test failed, or the current DTC, clears when the diagnostic runs and does not fail.
A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic.
Use a scan tool in order to clear the MIL/DTC.
Diagnostic Aids
Important
Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM\TAC modules.
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 Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Important
If the I/P is completely inoperative, refer to Body and Accessories for further diagnosis.
Further circuit diagnosis may require I/P removal. Check the circuit from the PCM to the tachometer for being open, shorted to ground or, voltage. If you can not find any trouble, follow the appropriate I/P diagnostic procedure.
