Engine Controls Self-Diagnostics - 6.6L Diesel: Other Chevrolet Silverado 2500

Code Types

There are 4 types of DTC categories

1. Type "A" Emissions related. Illuminates MIL the first time DTC sets.
2. Type "B" Emissions related. Illuminates MIL if fault is active for 2 consecutive driving cycles.
3. Type "C" Non-emissions related. Does not illuminate MIL, but will illuminate SERVICE light.
4. Type "D" Non-emissions related. Does not illuminate MIL or SERVICE light.

Freeze Frame/Failure Records

ECM stores one freeze frame record (failure record "0") for the first failed test that sets a DTC and illuminates MIL. Freeze frame will not be overwritten unless a misfire or fuel trim DTC is set. Failure records are stored when any DTC is set. Six additional failure records can be stored in ECM. Failure records will be stored for all types of codes, whether or not the MIL is illuminated. If more than 6 DTCs are set, oldest DTC is deleted as newest DTC is stored. Typical failure record data includes

1. Air/fuel ratio.
2. Airflow rate.
3. Fuel trim.
4. Engine speed.
5. Engine load.
6. Engine coolant temperature.
7. Vehicle speed.
8. Throttle position angle.
9. Manifold absolute pressure.
10. Injector base pulse width.
11. Loop status.

Monitors

1. Comprehensive Component Monitor Monitors ECM systems for opens, shorts grounds and out-of-range sensors. Also monitors rationality of sensors. Rationality is whether the sensors value is consistent with the operating conditions of the other sensors.
2. Misfire Monitor Monitors engine misfire using crankshaft sensor to determine location and severity of misfire. A catalyst damaging misfire will flash the MIL, and a non-catalyst damaging misfire is a normal type "B" code.
3. Fuel Trim Monitor Monitors short and long term fuel trim for being at maximum lean or rich limit.
4. Oxygen Sensor Monitor Monitors all oxygen sensors for maximum voltage level, minimum voltage level and lean rich/rich lean switching rate.
5. Oxygen Sensor Heater Monitor Monitors oxygen sensor heater by watching sensor's time-to-activity after a cold start.
6. Catalyst Monitor Monitors catalyst efficiency by comparing activity rate of precatalyst oxygen sensor and postcatalyst oxygen sensor.
7. EGR Monitor Monitors operation and flow rate of EGR system.
8. EVAP Monitor Monitors EVAP system for large leaks, small leaks and purge flow.
9. Secondary Air Monitor Monitors secondary air operation.

INTERMITTENT CONDITIONS

Note. Intermittent is a DTC or symptom, with a condition that cannot be duplicated.

Preliminary

Perform the Diagnostic System Check-Engine Controls before starting. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS .

Control Module Power & Grounds, & Component Power & Grounds

Poor power or ground connections can cause widely varying symptoms.

1. Test all control module power circuits. Many vehicles have multiple circuits supplying power to the control module. Other components in the system may have separate power circuits that may also need to be tested. Inspect connections at the module or component connectors, fuses, and any intermediate connections between the power source and the module or component. A test lamp or a Digital Multimeter (DMM) may indicate that voltage is present, but neither tests the ability of a circuit to carry sufficient current. Ensure that the circuit can carry the current necessary to operate the component. See POWER DISTRIBUTION article in WIRING DIAGRAMS.
2. Test all control module ground and system ground circuits. The control module may have multiple ground circuits. Other components in the system may have separate grounds that may also need to be tested. Inspect grounds for clean and tight connections at the grounding point. Inspect the connections at the component and in splice packs, where applicable. Ensure that the circuit can carry the current necessary to operate the component. See GROUND DISTRIBUTION article in WIRING DIAGRAMS.

Temperature Sensitivity

1. An intermittent condition may occur when a component or connection reaches normal operating temperature. The condition may occur only when the component or connection is cold, or only when the connection is hot.
2. The following data may help to diagnose this type of intermittent condition: Freeze Frame/Failure Records. Scan tool snapshot. Vehicle data recorder.
3. If the intermittent is related to heat, review the following data: High ambient temperatures. Underhood or engine generated heat. Circuit generated heat due to a poor connection, or high electrical load. Higher than normal load conditions, such as towing.
4. If the intermittent is related to cold, review the following data: Low ambient temperatures. In extremely low temperatures, ice may form in a connection or component. Test for water intrusion. The condition only occurs on a cold start. The condition is not present after the vehicle warms up.
5. Information from the customer may help to determine if the trouble follows a pattern that is temperature related.

Incorrect ECM Programming

1. There are only a few situations when reprogramming a ECM is appropriate, such as the following: A new service ECM is installed. A ECM from another vehicle is installed. Revised software or calibration files have been released for this vehicle.
2. Verify that the ECM contains the correct software or calibration. If incorrect programming is found, reprogram the ECM with the most current software or calibration. See «ENGINE CONTROL MODULE»(ref-138411-S14665279672002041200000) under PROGRAMMING.

Duplicating Failure Conditions

1. If none of the previous tests are successful, attempt to duplicate or capture the failure conditions.
2. Freeze Frame/Failure Records data, where applicable, contains the conditions that were present when the DTC set. Perform the following procedure: Review and record Freeze Frame/Failure Records data. Clear the DTCs using the scan tool. Turn the key to OFF and wait 15 seconds. Operate the vehicle under the same conditions that were noted in Freeze Frame/Failure Records data, as closely as possible. The vehicle must also be operating within the Conditions for Running DTC. Monitor DTC Status for the DTC being tested. The scan tool will indicate Ran, when the enabling conditions have been satisfied long enough for the DTC to run. The scan tool will also indicate whether the DTC passed or failed.
3. An alternate method is to drive the vehicle with the Digital Multimeter (DMM) connected to a suspected circuit. An abnormal reading on the DMM when the problem occurs, may help you locate the problem.

Vehicle Data Recorder

The J 42598 Vehicle Data Recorder is connected to the Data Link Connector (DLC) and sent with the customer. The J 42598 captures data for later retrieval and analysis by the technician. Refer to the vehicle data recorder user instructions for more information.

Disconnect Battery

Note. On many OBD-II systems, ECM will retain memory for an extended period of time with battery disconnected. Memory may be retained for several days.

Disconnecting ECM power or battery ground will clear all ECM memory including DTCs, freeze frame, failure records, adaptive learning and system monitors.

Warm-up Cycles

If fault that caused DTC to set is repaired, ECM will begin to count warm-up cycles. After 40 consecutive warm-up cycles with no further faults, ECM will automatically clear DTC from memory.

ENGINE CONTROL MODULE

Note. Programing Engine Control Module requires a compatible scan tool and a Techline® terminal. Procedure uses a Tech 2 scanner.

Remote Programming

Note. DO NOT program a control module unless you are directed by a service procedure or you are directed by a technical service bulletin. Programming a control module at any other time will not permanently correct a customer's concern.

Before Programming a Control Module

1. Vehicle system voltage: There is no charging system concern. All charging system concerns must be repaired before programming a control module. Battery voltage is greater than 12 volts but less than 16 volts. The battery must be charged before programming the control module if the battery voltage is low. A battery charger is NOT connected to the vehicle's battery. Incorrect system voltage or voltage fluctuations from a battery charger, may cause programming failure or control module damage. Turn OFF or disable any system that may put a load on the vehicle's battery. Twilight sentinel. Interior lights. Daytime Running Lights (DRL). Applying the parking brake, on most vehicles, disables the DRL system. See Owners manual. Heating, Ventilation, and Air Conditioning (HVAC) systems. Engine cooling fans, etc.
2. The ignition switch is in the proper position. The scan tool prompts you to turn ON the ignition, with the engine OFF. DO NOT change the position of the ignition switch during the programming procedure, unless instructed to do so.
3. All tool connections are secure. RS-232. The connection at the Data Link Connector (DLC) is secure. Voltage supply circuits.
4. DO NOT disturb the tool harnesses while programming. If an interruption occurs during the programming procedure, programming failure or control module damage may occur.

Remote Programming

1. Turn OFF the ignition.
2. Install the Tech 2™ to the Data Link Connector (DLC).
3. Turn ON the ignition, with the engine OFF.
4. Turn OFF all vehicle accessories.
5. With the Tech 2™, select Service Programming.
6. Identify vehicle information as requested by the Tech 2™.
7. Select the type of module you are programming.
8. Select the type of programming to be performed.
9. Verify the displayed VIN with the vehicle VIN. If the displayed VIN does not match the actual VIN, write down the actual VIN and correct the VIN at the Techline™ terminal.
10. When complete, Exit Service Programming.
11. Turn OFF the Tech 2™ and disconnect the Tech 2™ from the vehicle.
12. Turn OFF the ignition.
13. Connect the Tech 2™ to the Techline™ terminal.
14. Select Service Programming.
15. Select Tech 2™ as the tool you are using.
16. Select the type of programming to be performed.
17. Verify the displayed VIN with the vehicle VIN. Correct the VIN as necessary.
18. Select the type of module you are programming.
19. Identify what type of programming that you are performing. Normal. This type of programming is for updating an existing calibration or programming a new controller. Vehicle Configuration Index (VCI). This selection is used if the vehicle VIN is unavailable or not recognized by the Techline™ terminal. You will need to contact the Techline™ Customer Support center to use this option. Reconfigure. This is to reconfigure a vehicle, such as tire size and axle ratio changes.
20. Select the appropriate calibration file.
21. Ensure all connections are secure.
22. Select Reprog to initiate the download of the new calibration to the Tech 2™.
23. After the download is complete, turn OFF the Tech 2™.
24. Disconnect the Tech 2™ from the Techline™ terminal.
25. Install the Tech 2™ to the DLC.
26. Turn ON the Tech 2™.
27. Turn ON the ignition, with the engine OFF.
28. Select Service Programming.
29. Select Program.
30. After the download is complete, EXIT Service Programming.
31. Turn OFF the ignition for 30 seconds.
32. Turn OFF the Tech 2™.
33. If a control module is replaced the following service procedures must be performed: «ENGINE OIL LIFE RESET»(ref-138411-S39661141432002041200000) , «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-138411-S14518117712002041200000) under INSPECTION/MAINTENANCE PROCEDURES, and «THEFT DETERRENT PASSWORD LEARN PROCEDURE»(ref-138411-S42261530142002041200000) .

Programming Verification

1. With a scan tool, clear the DTCs.
2. Attempt to start the engine.
3. Repeat the Service Programming procedure if the engine does not start or operates poorly. Perform the following procedures before programming the ECM: Ensure the control module and DLC connections are okay. Ensure the Techline™ operating software is up to date. Ensure the calibration part number is correct for the vehicle.
4. Attempt to program the control module. If the control module still cannot be programmed properly, replace the control module. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. You must program the replacement control module.

Off-Board Programming

Note. DO NOT program a control module unless you are directed by a service procedure or you are directed by a technical service bulletin. Programming a control module at any other time will not permanently correct a customer's concern. The Off-Board Programming is used in situations where a control module must be programmed without having the vehicle present. The Off-Board Programming Adapter must be used to perform the Off-Board Programming procedure. The adapter allows the control module to power up and allows the Tech 2™ to communicate with the control module. DO NOT disturb the tool harnesses while programming. If an interruption occurs during the programming procedure, programming failure or control module damage may occur.

Before Programming a Control Module

1. Ensure that all connections are secure at the following locations: The Off-Board Programming Adapter. The Tech 2™. The control module. The Techline™ terminal.

Off-Board Programming

1. Obtain the VIN of the vehicle for which the control module is being programmed.
2. With the Techline™ terminal, select Service Programming.
3. Select Tech 2™, Reprogram ECU, and Off-Board Programming Adapter as the ECU location.
4. Connect the control module, Off-Board Programming Adapter, and the Tech 2™ as described on the Techline™ terminal. Ensure you use the correct harness connector from the Off-Board Programming Adapter kit.
5. With the Tech 2™, select Service Programming Request Information function. The Tech 2™ communicates with the control module and receives the access code.
6. With the Tech 2™, exit the Service Programming Request Information.
7. Disconnect the Tech 2™ from the Off-Board Programming Adapter.
8. Connect the Tech 2™ to the Techline™ terminal.
9. Turn ON the Tech 2™.
10. With the Techline™ terminal, enter the VIN of the vehicle that will be receiving the control module.
11. The Techline™ terminal will display the message, attaching to database.
12. Identify what type of programming that you are performing.
13. Select the appropriate calibration file.
14. Ensure all connections are secure.
15. The Techline™ terminal displays a summary screen that summarizes your selections. After confirming you choices, the Techline™ terminal automatically loads the calibration files to the Tech 2™.
16. After the download is complete, turn OFF the Tech 2™.
17. Disconnect the Tech 2™ from the Techline™ terminal.
18. Connect the Tech 2™ to the Off-Board Programming Adapter.
19. With the Tech 2™, select Service Programming.
20. With the Tech 2™, select Program.
21. After the download is complete, exit Service Programming.
22. Turn OFF the Off-Board Programming Adapter.

THEFT DETERRENT PASSWORD LEARN PROCEDURE

Note. The body control module (BCM) must be programmed with the proper RPO configurations before performing learn procedures. See PROGRAMMING in appropriate BODY CONTROL MODULES article. If replacing the BCM with a GM Service Parts Operations (SPO) replacement part, the module will learn passlock™ sensor data code immediately. The existing ECM however, must learn the new fuel continue password when the BCM is replaced. If replacing a ECM with a GM Service Parts Operations (SPO) replacement part, after programming, these modules will learn the incoming fuel continue password immediately upon receipt of a password message. Once a password message is received, and a password is learned, a learn procedure must be performed to change this password again. A ECM which has been previously installed in another vehicle will have learned the other vehicle's fuel continue password and will require a learn procedure after programming to learn the current vehicle's password.

Use this procedure after replacing

1. Passlock™ Sensor
2. BCM
3. ECM

10 Minute Learn Procedure

Note. This procedure requires a Tech 2 scan tool and a Techline terminal with current SPS (Service Programming System) software.

1. Connect the Tech 2 to the vehicle.
2. Select "Request Information" under "Service Programming".
3. Disconnect the Tech 2 from the vehicle and connect it to a techline terminal.
4. On the techline terminal, select "Theft Module Re-Learn" under "Service Programming".
5. Disconnect the Tech 2 from the techline terminal and connect it to the vehicle.
6. Turn ON the ignition, with the engine OFF.
7. Select "VTD Re-Learn" under "Service Programming".
8. Attempt to start the engine, then release the key to ON (vehicle will not start).
9. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF (the vehicle is now ready to relearn the Passlock™ Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK).
10. Turn OFF the ignition, and wait 5 seconds.
11. Start the engine (the vehicle has now learned the password).
12. With the Tech 2 (scan tool), clear any DTCs.

30 Minute Learn Procedure

1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON (vehicle will not start).
3. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds.
5. Repeat steps 1 - 4 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the Passlock™ Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK).
6. Start the engine (the vehicle has now learned the Passlock™ Sensor Data Code and/or password).
7. With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles).

DRIVE CYCLES

See INSPECTION/MAINTENANCE SYSTEM CHECK .

Conditions for Updating I/M System Status

Each system requires at least one, and sometimes several, diagnostic tests. The results of these tests are reported by a Diagnostic Trouble Code (DTC). A system monitor is complete when either all of the DTCs comprising the monitor have Run and Passed, or any one of the DTCs comprising the monitor have illuminated the Malfunction Indicator Lamp (MIL). Once all of the tests are complete, the I/M System Status display will indicate YES in the Completed column. For example, when the heated oxygen sensor (HO2S) Heater Test indicates YES, all of the oxygen sensor heaters have been diagnosed. If the vehicle has four heated oxygen sensors, all four heater circuits have been diagnosed. The I/M System Status will indicate NO under the Completed column when any of the required tests for that system have not run. The following is a list of conditions that would set the I/M System Status indicator to NO

1. The vehicle is new from the factory and has not yet been driven through the necessary drive conditions to complete the tests.
2. The battery has been disconnected or discharged below operating voltage.
3. The control module power or ground has been interrupted.
4. The control module has been reprogrammed.
5. The control module DTCs have been cleared as part of a service procedure.

Monitored Emission Control Systems

The OBD-II System monitors all emission control systems that are on-board. Not all vehicles have a full complement of emission control systems. For example, a vehicle may not be equipped with secondary Air Injection (AIR) or Exhaust Gas Recirculation (EGR). The OBD-II regulations require monitoring of the following

1. Comprehensive component monitoring. Emission related inputs and outputs.
2. EGR system.
3. Misfire monitoring.

For the specific DTCs required for each system, see

INSPECTION/MAINTENANCE SYSTEM DTCS

table.

Procedure

1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM. Repair any DTCs or driveability concerns that would prevent the I/M System Status tests from completing. Did you find and repair a DTC or driveability concern? If yes, go to step 3 . If no, go to next step.
2. Review any service bulletins for software updates that may prevent I/M readiness. Perform any reprogramming or repairs indicated by the service bulletins. Was a reprogramming or repair service required? If yes, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-138411-S14518117712002041200000) . If no, go to next step.
3. With a scan tool, observe the I/M System Status display. Is more than one test indicating a NO status? If yes, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-138411-S14518117712002041200000) . If no, go to the I/M System Set Procedure for the indicated system.

1. Did you perform the Inspection/Maintenance (I/M) System Check? If yes, go to next step. If no, see «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-138411-S05997824532002041200000) .
2. Ensure the vehicle is within the Conditions for Running. Turn OFF all of the accessories (e.g., A/C, blower fan, etc.). Set the vehicle parking brake. Verify the transmission is in Park for automatic transmissions and Neutral for manual transmissions. Start the engine, and allow the engine to idle. Allow the engine to idle for 2 minutes. When complete, go to next step.
3. In order for the next group of tests to run, the vehicle must operate in the following conditions: Acceleration at part throttle to 50 MPH with this speed maintained until the engine reaches operating temperature. This may be up to 10 minutes depending on the start up coolant temperature. Continue operation under these conditions for an additional 3 minutes. After procedure, go to next step.
4. In order for the next group of tests to run, the vehicle must operate in the following conditions: Acceleration at 75 percent throttle until a speed of 68 MPH is attained. Deceleration to 0 MPH. Engine idling for 2 minutes while the following criteria is maintained: Service brake depressed. Automatic transmission in Drive. Manual transmission in Neutral with the clutch pedal depressed. When complete, go to next step.
5. With a scan tool, observe the I/M System Status display. Did all of the I/M System Status indicators update to YES? If yes, go to next step. If no, go to the I/M System Set Procedure for the indicated systems.
6. With a scan tool, observe the Emission Related DTC portion of the I/M System Status display. Does the scan tool indicate any Emission Related DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. Did you perform the Inspection/Maintenance (I/M) System Check? If yes, go to next step. If no, see «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-138411-S05997824532002041200000) .
2. Ensure the vehicle is within the Conditions for Running specified in the supporting text. Turn OFF all of the accessories (e.g., A/C, blower fan, etc.). Start the engine and allow the engine to idle for 2 minutes. For this test to run, the vehicle must operate in the following conditions: Acceleration at part throttle to 50 MPH with this speed maintained until the engine reaches operating temperature. This may be up to 10 minutes depending on the start up coolant temperature. Continue the operating conditions for an additional 3 minutes after the engine reaches operating temperature. After the specified time has elapsed, vehicle requires acceleration at 75 percent throttle until a speed of 68 MPH is attained. Review the I/M System Status display with a scan tool. Did the Component Monitoring System Status update to YES? If yes, go to step 5 . If no, go to next step.
3. With a scan tool, observe the DTC Information. Does the scan tool indicate any failed DTCs? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, go to next step.
4. To determine which DTCs are required to run in order to complete this test, see «INSPECTION/MAINTENANCE SYSTEM DTCS»(ref-138411-S22893109092002041200000) table. With a scan tool, observe the Not Ran Since Code Cleared display. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC menu of the scan tool. Operate the vehicle within the Conditions for Running DTC. Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat procedure for any additional required DTCs that have not run. With a scan tool, observe the I/M System Status display. Did the Component Monitoring System Status update to YES? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S26735528532002041200000) .
5. With a scan tool, observe the Emission Related DTC portion of the I/M System Status display. Does the scan tool indicate any Emission Related DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

1. Did you perform the Inspection/Maintenance (I/M) System Check? If yes, go to next step. If no, see «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-138411-S05997824532002041200000) .
2. Ensure the vehicle is within the Conditions for Running. Set the vehicle parking brake. Verify the transmission is in Park for automatic transmissions and Neutral for manual transmissions. Turn OFF all of the accessories (e.g., A/C, blower fan, etc.). Start the engine, and allow the engine to idle. Allow the engine to idle for 2 minutes or until the I/M System Status indicator updates to YES. Did the Misfire Monitoring System Status update to YES? If yes, go to step 5 . If no, go to next step.
3. With a scan tool, observe the DTC Information. Does the scan tool indicate any failed DTCs? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, go to next step.
4. To determine which DTCs are required to run in order to complete this test, see «INSPECTION/MAINTENANCE SYSTEM DTCS»(ref-138411-S22893109092002041200000) table. With a scan tool, observe the Not Ran Since Code Cleared display. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC menu of the scan tool. Operate the vehicle within the Conditions for Running DTC. Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat procedure for any additional required DTCs that have not run. With a scan tool, observe the I/M System Status display. Did the Misfire Monitoring System Status update to YES? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-138411-S12804033532002041200000) .
5. With a scan tool, observe the Emission Related DTC portion of the I/M System Status display. Does the scan tool indicate any Emission Related DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) . If no, system is okay.

SUMMARY

If no hard fault DTCs are present, driveability symptoms exist or intermittent DTC(s) exist, proceed to appropriate TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO-START, etc.) or intermittent diagnostic procedures.

MALFUNCTION INDICATOR LAMP INOPERATIVE

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS article. For connector terminal identification, see CONNECTOR IDENTIFICATION .

MALFUNCTION INDICATOR LAMP ALWAYS ON

Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS article. For connector terminal identification, see CONNECTOR IDENTIFICATION .