P2158
DTC P0500, P0501, P062C, P2158, or P2159
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.
DTC Descriptor
DTC P0500
- Vehicle Speed Sensor (VSS) Circuit
DTC P0501
- Vehicle Speed Sensor (VSS) Performance
DTC P062C
- Control Module Vehicle Speed Performance
DTC P2158
- Vehicle Speed Sensor (VSS) 2 Circuit
DTC P2159
- Vehicle Speed Sensor (VSS) 2 Performance
Circuit/System Description
The A/Trans output speed sensor assembly has 2 internal hall-effect type sensors, and is capable of sensing both speed and direction. The A/Trans output speed sensor assembly mounts to the A/Trans case assembly and is connected to the control solenoid (w/body and TCM) valve assembly through the A/Trans wiring harness assembly and connectors. The sensor faces the front differential drive pinion (w/transfer gear) gear 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 front differential drive pinion (w/transfer gear) gear assembly rotates, the sensor produces a signal frequency based on the rotating speed of the machined surface of the front differential drive pinion (w/transfer gear) gear assembly.
The two sensor elements in the A/Trans output speed sensor 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 to the TCM. This signal is interpreted by the TCM for speed and direction and is transmitted through the GMLAN circuits to the engine control module (ECM). The electronic brake control module (EBCM) interprets and averages the 4 wheel speed inputs from the 4 wheel speed sensors and transmits this signal through the GMLAN circuits to the ECM. The ECM compares the vehicle speed signal from the TCM with the average of the 4 EBCM wheel speed sensor signals.
Conditions for Running the DTC
P0500
The ECM detects TCM vehicle speed between 7 km/h (6 mph) and 275 km/h (171 mph).
P0501
The ECM detects TCM vehicle speed.
P062C
* No TCM DTCs P0721, P0722, or P0723.
* No EBCM DTCs C0035-C0050, C1207-C1210, C1221-C1228, C1232-C1235, C005A, C0245, or C122E.
* No ECM DTCs P0501 or P215B.
* The ECM detects vehicle speed for greater than 1 second.
P2158
The ECM detects TCM vehicle speed between 7 km/h (6 mph) and 275 km/h (171 mph).
P2159
The ECM detects TCM vehicle speed.
Conditions for Setting the DTC
P0500
TCM vehicle speed signal reported to the ECM has not changed for 11 seconds, when EBCM wheel speed signal has changed.
P0501
TCM vehicle speed signal reported to the ECM is greater than 275 km/h (171 mph) for 3 seconds.
P062C
The difference between the TCM vehicle speed signal and the EBCM wheel speed signal reported to the ECM is greater than 12 mph.
P2158
EBCM wheel speed signal reported to the ECM has not changed for 11 seconds, when EBCM wheel speed signal has changed.
P2159
EBCM wheel speed signal reported to the ECM is greater than 275 km/h (171 mph) for 3 seconds.
Action Taken When the DTC Sets
DTCs P0500, P0501, P062C, P2128, and P2159 are Type A DTCs.
Conditions for Clearing the DTC
DTCs P0500, P0501, P062C, P2128, and P2159 are Type A DTCs.
Diagnostic Aids
* Inspect the A/Trans wiring harness assembly, harness, connector pins for metallic debris and front differential drive pinion (w/transfer gear) gear assembly machined face for damage or misalignment. Proper torque of the A/Trans output speed sensor assembly mounting bolt is critical to proper OSS operation.
* • Inspect the ABS wheel speed sensors and related wiring harness connector pins for metallic debris, corrosion, damage or misalignment.
Reference Information
Schematic Reference
* Automatic Transmission Controls Schematics (Electrical Diagrams)
* Antilock Brake System Schematics (2 Mode Hybrid) (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Circuit/System Verification
Operate the vehicle while observing the Transmission vehicle speed and ABS wheel speed sensor parameters on the scan tool.
The vehicle speed and ABS wheel speed signal displays should not vary by greater than 10 km/h (6 mph).
Circuit/System Testing
Note: 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.
• If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
2. Verify that ABS DTCs C0035-C0050, C1207-C1210, C1221-C1228, C1232-C1235, C005A, C0245, or C122E are not set in the EBCM.
• If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
3. Program the ECM with the latest software version and retest for DTCs.
• If the DTC resets, replace the ECM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Control Module References (Programming and Relearning)for ECM replacement, setup, and programming