P081B
DTC P081A or P081B
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 Descriptors
DTC P081A
- Brake Transmission Shift Interlock Solenoid Actuator - Short to Ground/Open
DTC P081B
- Brake Transmission Shift Interlock Solenoid Actuator - Short to Voltage
Diagnostic Fault Information
Circuit/System Description
The transmission range switch is an integral part of the transmission control module (TCM). As the gear range selector lever is moved, the state of the starter inhibit circuit may change, causing the circuit to open or close. An open circuit indicates a drive range and a low voltage signal, 0 V, at the body control module (BCM). A closed circuit indicates PARK or NEUTRAL and a high voltage, 12 V, signal at the BCM. The BCM uses the starter inhibit circuit status from the TCM in order to enable starter operation.
Conditions for Running the DTC
P081A, P081B
* The ignition voltage is 9.0-18.0 V.
* The transmission is not in emergency mode.
Conditions for Setting the DTC
P081A
* Start lock output is "On" and start lock monitor signal indicates "Off" for more than 10 ms.
* After consecutive 2 times of above detection.
P081B
* Start lock output is "Off" and start lock monitor signal indicates "On" for more than 100 ms.
* After consecutive 2 times of above detection.
Action Taken When the DTC Sets
* DTCs P081A and P081B are Type D DTCs.
* No engine start possible.
Conditions for Clearing the DTC
* DTCs P081A and P081B are Type D DTCs.
* Start lock output is "On" and start lock monitor signal indicates "On" and/or start lock output is "Off" and start lock monitor signal indicates "Off" for more than 1 s.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics AF40-6 (MDK) - Automatic Transmission
Connector End View Reference
Component Connector End Views Sunshade - Left
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
Description and Operation
Transmission Component and System Description Transmission Component and System Description
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Transmission Range Switch parameter while selecting each transmission range: park (P), reverse (R), neutral (N), drive (D).
2. Verify Each selected transmission range should correspond to the correct scan tool parameter displayed data.
• If the selected transmission range not correspond to the scan tool parameter displayed data
Refer to Circuit/System Testing
• If the selected transmission range correspond to the scan tool parameter displayed data
3. Verify the engine start only in range position park (P) and neutral (N). The engine does not start in all other range positions.
• If the engine does not start at all or the engine starts in another range position than P and N
Refer to Circuit/System Testing
• If the Engine start only in range position P and N
4. Verify there are no other DTCs are set.
• If any other DTC are set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
• If none DTC are set
5. Operate the vehicle within the Conditions for Running the DTC. It may be helpful to operate the vehicle within the conditions identified from the Freeze Frame/Failure Records data.
6. Verify DTC P081A or P081B is not set.
• If the DTC sets
Refer to Circuit/System Testing.
• If the DTC does not set
7. All OK.
Circuit/System Testing
Note: Circuit/System Verification must be performed before proceeding with Circuit/System Testing.
1. Ignition OFF, and all vehicle systems OFF. Disconnect the X2 harness connector at the K20 Engine Control Module and the X1 harness connector at the K71 Transmission Control Module. It may take up to 2 min for all vehicle systems to power down.
2. Test for infinite resistance between the control circuit terminal 5 at the X1 harness connector K71 Transmission Control Module and ground.
• If less than infinite resistance
Repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit terminal 5 at the X1 harness connector K71 Transmission Control Module end to end.
• If 2 ohms or greater
Repair the open/high resistance in the circuit.
• If less than 2 ohms
4. Ignition ON, test for less than 1 V between the control circuit terminal 5 at the X1 harness connector K71 Transmission Control Module and ground.
• If 1 V or greater
Repair the short to voltage on the circuit.
• If less than 1 V
5. Verify the DTC does not set while operating the vehicle under the Conditions for Running the DTC.
• If the DTC sets
Replace the K71 Transmission Control Module.
• If the DTC does not set
6. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Refer to Control Module References Control Module References for TCM replacement, programming and setup.
* Perform the Transmission Adaptive Functions Transmission Adaptive Functions.