Automatic Transmission - MVA 4 Speed
DTC P0793
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0793
- Intermediate Shaft Speed Sensor A
Diagnostic Fault Information
Circuit/System Description
The output shaft speed sensor is a two wire sensor. The powertrain control module (PCM) supplies a voltage signal circuit and a low reference circuit to the output shaft speed sensor. The PCM compares the input shaft speed sensor signal to the output sensor speed signal and appropriately controls the engine torque and transmission hydraulic pressure for shift timing.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
* Vehicle speed is greater than 50 km/h (31 mph).
* Vehicle is operating in 2nd, 3rd, or 4th gear while in the shift lever position of D.
* Speed sensor signal is less than 300 RPM.
Action Taken When the DTC Sets
DTC P0793 is a type A DTC.
Conditions for Clearing the DTC
DTC P0793 is a type A DTC.
Diagnostic Aids
The battery must be fully charged. Refer to Battery Inspection/Test (Battery Inspection/Test).
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Powertrain Control Module Scan Tool Information (Scan Tool Testing and Procedures) for scan tool information
Circuit/System Verification
1. Inspect the transmission fluid for the correct level.
2. Operate the vehicle at 80 km/h (50 mph) with a scan tool. Observe the output speed sensor signal and the instrument panel speedometer reading. The output speed sensor signal and the instrument panel speedometer reading should indicate the same value.
3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the PCM harness connector X2.
2. Test for 560-680 ohm on the PCM harness connector X2 between terminals 101 and terminal 102.
• If not within the specified value, test the output shaft speed sensor signal circuits for an open/high resistance. If the circuits test normal, replace the output shaft speed sensor.
3. Test for greater than 10k ohm on the PCM harness connector X2 between terminal 102 and ground.
• If not within the specified value, test the low reference circuit for a short to ground. If the circuit tests normal, replace the output shaft speed sensor.
4. Test for greater than 10k ohm on the PCM harness connector X2, between terminal 101 and ground.
• If not within the specified value, test the voltage reference circuit for a short to ground. If the circuit tests normal, replace the output shaft speed sensor.
5. If all circuits test normal, replace the PCM.
Component Testing
1. Ignition OFF, disconnect the output shaft speed sensor harness connector.
2. Test for 560-680 ohm between terminals 1 and 2 on the output shaft speed sensor.
• If not within the specified value, replace the output shaft speed sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.
* Vehicle Speed Sensor Replacement (MVA 4 Speed - Automatic Transmission)
* Powertrain Control Module Replacement (Service and Repair)
* Powertrain Control Module Programming and Setup (Testing and Inspection)