GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0717: Input Speed Sensor Circuit Low Voltage

DTC P0722: Output Speed Sensor Circuit Low Voltage

Circuit/System Description

The input speed sensor (ISS) and output speed sensor (OSS) are hall-effect type sensors. The sensors receive supply voltage from the transmission control module (TCM) and produce a fixed amplitude square wave signal with a frequency proportionate to transmission gear rotations.

Conditions for Running the DTC

Fail Case 1

    • No TR Switch DTCs, P0706, P0707, or P0708
    • No TFT Sensor DTCs P0711, P0712, or P0713
    • No other Speed Sensor DTCs P0717 or P0722
    • The engine is running.
    • The transmission is not in Emergency Mode.
    • The transmission range is D, M, or L

Fail Case 2

    • The engine is running.
    • The transmission is not in Emergency Mode.

Conditions for Setting the DTC

DTC P0717

Fail Case 1

The TCM detects no pulse signal from Input Speed sensor when there are 6 pulses from the Output Speed sensor.

Fail Case 2

The TCM detects less than 45 pulses or greater than 545 pulses from the Input Speed sensor in 0.1 second, 300 occurrences.

DTC P0722

Fail Case 1

The TCM detects no pulse signal from Output Speed sensor when there are 12 pulses from the Input Speed sensor

Fail Case 2

The TCM detects less than 45 pulses or greater than 545 pulses from the Output Speed sensor in 0.1 second, 300 occurrences.

Action Taken When the DTC Sets

DTC P0717 and P0722

    • Type A DTC
    • The transmission will operate in 5th gear in D or M range, 2nd gear in L range.

Conditions for Clearing the DTC

DTC P0717 and P0986 are Type A DTCs

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

    •  Electrical Center Identification Views
    •  Component Connector End Views
    •  Splice Pack Connector End Views
    •  Inline Harness Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

    •  Diagnostic Trouble Code (DTC) Type Definitions
    •  Diagnostic Trouble Code (DTC) List/Type

Scan Tool Reference

Control Module References for scan information.

Circuit/System Verification

  1. Ignition ON, observe the DTC information with a scan tool.
  2. Record Freeze Frame and Failure Records.
  3. Clear DTCs.
  4. Operate the vehicle under the conditions observed in the Failure Records.
  5. Observe the DTC information with the scan tool.

Circuit/System Testing

  1. Ignition OFF, disconnect the 4-way Speed Sensor Connector (C3) at the TCM.
  2. Ignition ON, Test for 9-12 volts between the high signal circuit, TCM terminal C3-3 (ISS) or C3-2 (OSS) and low signal circuit, TCM terminal C3-4 (ISS) or C3-1 (OSS).
  3. If not within the specified range, replace the TCM. Refer to Transmission Control Module Removal procedure and Transmission Control Module Installation procedure.
  4. If the circuits test normal, test or replace the speed sensor.

Component Testing

  1. Test the speed sensor wiring. There should not be an open, short to ground, or a short together condition.
  2. If one of the above conditions is found, repair the circuit.
  3. If all circuits test normal, replace the sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.