Manual Transmission - Aisin AY6
DTC P0501 or P0502
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 Descriptors
DTC P0501
- Vehicle Speed Sensor (VSS) Performance
DTC P0502
- Vehicle Speed Sensor (VSS) Circuit Low Voltage
Diagnostic Fault Information
Typical Scan Tool Information
Circuit/System Description
Vehicle speed information is provided to the engine control module (ECM) by the vehicle speed sensor (VSS). The VSS consists of a hall-effect sensor mounted to the transmission case which interfaces with a rotor pressed onto the transmission output shaft. The hall-effect sensor contains a permanent magnet and a semiconductor plate to which ignition voltage is applied. As the output shaft spins, the rotor directs the field of the permanent magnet either toward or away from the plate. The VSS produces a frequency signal that is proportional to vehicle speed. The ECM converts the VSS signal to vehicle speed, displayed on the scan tool in kilometers per hour or miles per hour. The ECM also uses the VSS signal to generate the 4,000 pulses per mile vehicle speed signal used by the instrument cluster.
Conditions for Running the DTC
* The engine speed is greater than 1800 RPM for 3 seconds.
* The engine coolant temperature (ECT) is greater than 40°C (104°F).
Conditions for Setting the DTC
The VSS indicates a speed of less than 0 km/h (0 mph) for 4 seconds.
Action Taken When the DTC Sets
* P0501 and P0502 are Type B DTCs.
* The ECM disables cruise control.
Conditions for Clearing the MIL/DTC
P0501 and P0502 are Type B DTCs.
Diagnostic Aids
The battery must be fully charged and pass a battery test. Refer to Battery Inspection/Test (Battery Inspection/Test).
Reference Information
Schematic Reference
Manual Transmission Schematics (Aisin AY6 - Manual Transmission)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Transmission System Description and Operation (Aisin AY6 - Manual Transmission)
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)
Circuit/System Verification
1. Operate the vehicle on the road at 40 MPH. Observe the transmission vehicle speed sensor parameter with a scan tool. The VSS signal should match the instrument panel speedometer indicator.
2. 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.
Circuit/System Testing
1. Ignition OFF, disconnect the X2 harness connector at the ECM.
2. Disconnect the VSS harness connector.
3. Ignition OFF, test for less than 5 ohms of resistance between the ground circuit at the VSS harness connector terminal 2 and ground.
• If greater than the specified value, repair the open/high resistance condition.
4. Ignition ON, test for less than 1 volt between the signal circuit terminal 1 and ground at the VSS harness connector.
• If greater than the specified value, test the signal circuit for a short to voltage.
5. Ignition ON, test for greater than 11 volts between the ignition voltage circuit, at the VSS harness connector terminal 3, and ground.
• If less than the specified value, test the ignition voltage circuit for a short to ground or an open/high resistance.
6. Ignition ON, install a 3A fused jumper wire between the ignition voltage circuit terminal 3 and the signal circuit terminal 1 at the VSS harness connector. Test for greater than 11 volts at X2, terminal 43 of the ECM harness connector.
• If less than the specified value, test the VSS signal circuit for a short to ground, or an open/high resistance.
7. Remove the 3A fused jumper wire.
8. Ignition ON, engine OFF, transmission in NEUTRAL.
9. Install a 3A fused jumper wire between the ignition voltage circuit terminal 1 on the VSS harness connector and terminal 1 on the VSS. Connect a second jumper wire between the ground circuit terminal 2 on the VSS harness connector and terminal 2 on the VSS.
10. Test for greater than 0.15 volts AC, at terminal 1 on the VSS sensor, while rotating the rear wheels by hand.
• If less than the specified value, replace the VSS.
11. If all circuits test normal, replace the ECM.
Component Testing
1. Remove the VSS sensor. Refer to Vehicle Speed Sensor Replacement (Service and Repair).
2. Inspect and repair the VSS or the transmission for the following conditions:
* Loose or damaged VSS
* Excessive VSS to rotor gap
* Incorrect VSS rotor alignment
* Loose or damaged VSS rotor
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Vehicle Speed Sensor Replacement (Service and Repair)
* Engine Control Module Programming and Setup (V8) (Programming and Relearning)Engine Control Module Programming and Setup (V6) (Programming and Relearning)
* Engine Control Module Replacement (Service and Repair)