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 Descriptor

DTC P215C: Output Shaft Speed (OSS) - Wheel Speed Correlation

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

OSS Supply Voltage

P0722, P0723

P0722, P0723

P0722, P0723

P0721, P215C

OSS Signal

P0722, P0723

P0722, P0723

P0722, P0723

P0721, P215C

Typical Scan Tool Data

Transmission OSS

Circuit

Normal Range

Open/High Resistance

Short to Voltage

Operating Conditions: Engine running, normal operating temperature

OSS Signal

0-7,000 RPM

0 RPM

0 RPM

OSS Supply Voltage

--

0 RPM

0 RPM


OSS Supply Voltage

Circuit

Normal Range

Open/High Resistance

Short to Voltage

Operating Conditions: Key ON, Engine OFF or Engine running, normal operating temperature

OSS Signal

OK

OK

OK

OSS Supply Voltage

OK

Out of Range

Out of Range

8.3-9.3 Volts = OK, Any other voltage = Out of range

Circuit/System Description

The output speed sensor (OSS) assembly has 2 internal hall-effect type sensors, and is capable of sensing both speed and direction. The OSS mounts to the A/T rear case assembly and is connected to the control solenoid (w/body and TCM) valve assembly through a wire harness and connector. The sensor faces the hybrid direct, 2-3-4 clutch housing assembly machined teeth surface. The sensor receives 8.3-9.3 volts on the OSS supply voltage circuit from the transmission control module (TCM). As the output shaft rotates, the sensor produces a signal frequency based on the machined surface of the output shaft.

The two sensor elements in the OSS assembly are spaced approximately 1/2 a tooth apart.

    • When the vehicle is moving in a forward direction, sensor A detects a particular tooth before sensor B.
    • When the vehicle is moving in a reverse direction, sensor B detects a particular tooth before sensor A.

The electronics in the sensor combine the two signals and send a signal with a different pulse width. This signal is interpreted by the TCM for speed and direction and is transmitted through the GMLAN circuits to the engine control module (ECM) and the hybrid powertrain control module (HPCM). The ECM, HPCM, and TCM compare the OSS signal with the ABS wheel speed sensor signal.

Conditions for Running the DTC

The vehicle speed is greater than 10 km/h (6 mph).

Conditions for Setting the DTC

The TCM OSS signal and the average ABS wheel speed sensor and the drive motor signals differ by greater than 10 km/h (6 mph) for greater than 10 seconds.

Action Taken When the DTC Sets

    • P215C is a Type B DTC.
    • The TCM calculates output speed based on the ABS wheel speed and the drive motor speed signals.
    • The TCM calculates vehicle speed based on the wheel speed sensors.

Conditions for Clearing the DTC

P215C is a Type B DTC.

Diagnostic Aids

    • Vehicles equipped with a transfer case may set this DTC if the vehicle is moving while the transfer case is in the Neutral selection. Review the freeze frame records with a scan tool to identify if this DTC was set by the vehicle operator. Explain proper transfer case shifting procedures as necessary.
    • Inspect the OSS, harness, and connector pins for metallic debris and the hybrid direct, 2-3-4 clutch housing assembly machined teeth for damage or misalignment. Even one bent or misaligned tooth, and or contact with the OSS, may cause this DTC to set. Proper torque of 9-13 N·m (80-115 lb in) to the OSS mounting bolt is critical to proper OSS operation. The hybrid system is very sensitive to the OSS signal for overall operation.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

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

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information.

Special Tools

J 38522 Variable Signal Generator

Circuit/System Verification

Operate the vehicle at 16-32 km/h (10-20 mph) while observing the Transmission OSS and ABS wheel parameters on the scan tool. Inspect for the following mechanical conditions:

    • Loose, misaligned, OSS
    • Broken driveline components
The OSS and ABS wheel speed signal displays should not vary by greater than 10 km/h (6 mph).

Circuit/System Testing

Important:  For vehicles equipped with a transfer case, review Diagnostic Aids.

  1. Verify that OSS DTCs P0721, P0722, or P0723 are not set in the TCM.
  2. If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  3. Verify that ABS DTCs C0035-C0050, C1207-C1210, C1221-C1228, C1232-C1235, C005A, C0245, or C122E are not set in the electronic brake control module (EBCM).
  4. If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  5. Inspect the OSS, harness, and connector pins for metallic debris and the hybrid direct, 2-3-4 clutch housing assembly machined teeth for damage or misalignment. Even one bent or misaligned tooth, and or contact with the OSS, may cause this DTC to set. Proper torque of 9-13 N·m (80-115 lb in) to the OSS mounting bolt is critical to proper OSS operation. The hybrid system is very sensitive to the OSS signal for overall operation.
  6. If damage is observed, replace the damaged component.
  7. Program the control module which set the DTC with the latest software version and retest for DTCs.
  8. If the DTC resets, replace the control module which set the DTC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Output Speed Sensor Replacement for OSS replacement.
    •  Rear Case and Gasket Replacement for hybrid direct, 2-3-4 clutch housing assembly replacement.
    •  Control Module References for ECM or HPCM replacement, setup, and programming.