Diagnostic Trouble Code (DTC) P2264
DTC Description
Note : The symptom byte may not be displayed on a scan tool.
DTC P2264 (00): Water in Fuel Sensor Circuit
Circuit/System Description
A sensor mounted in the bottom of the fuel filter housing is use to detect water in the fuel. The engine control module (ECM) monitors the voltage at the WIF sensor signal circuit. If the voltage is incorrect, the ECM will set the DTC.
Conditions for Running the DTC
Conditions for Setting the DTC
- The ECM detects that the water in fuel sensor selftest signal error
Action Taken When the DTC Sets
- DTC P2264 is type Cnl DTC.
Conditions for Clearing the MIL/DTC
- DTC P2264 is type Cnl DTC.
Diagnostic Aids
DTC P2264
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | - Turn the ignition OFF.
- Disconnect the wiring harness connectors from the water in fuel (WIF) sensor and from the engine control module (ECM).
- Measure the voltage between the WIF sensor signal circuit and a good ground.
Is the voltage less than the specified value? | 0.3 V | Go to Step 3 | Go to Step 7 |
| 3 | Measure the resistance between the WIF sensor signal circuit and a good ground. Is the resistance greater than the specified value? | 500 kOhm | Go to Step 4 | Go to Step 8 |
| 4 | Measure the resistance of the WIF sensor signal circuit between the connectors at the WIF sensor and at the ECM. Is the resistance less than the specified value? | 5 Ohm | Go to Step 5 | Go to Step 9 |
| 5 | - Connect the wiring harness connector at the ECM.
- Turn the ignition ON, with the engine OFF.
- Measure the voltage between the WIF sensor voltage supply circuit and a good ground.
Is the voltage greater than the specified value? | 11 V | Go to Step 6 | Go to Step 10 |
| 6 | Measure the resistance between the WIF sensor ground circuit and a good ground. Is the resistance less than the specified value? | 5 Ohm | Go to Step 12 | Go to Step 11 |
| 7 | Repair the short to voltage in the WIF sensor signal circuit. Did you complete the repair? | - | Go to Step 13 | - |
| 8 | Repair the short to ground in the WIF sensor signal circuit. Did you complete the repair? | - | Go to Step 13 | - |
| 9 | Repair the open or high resistance in the WIF sensor signal circuit. Did you complete the repair? | - | Go to Step 13 | - |
| 10 | Repair the open or high resistance in the WIF sensor voltage supply circuit. Did you complete the repair? | - | Go to Step 13 | - |
| 11 | Repair the open or high resistance in the WIF sensor ground circuit. Did you complete the repair? | - | Go to Step 13 | - |
| 12 | Replace the WIF sensor. Did you complete the replacement? | - | Go to Step 13 | - |
| 13 | - Clear the DTCs with a scan tool.
- Turn OFF the ignition for 30 seconds.
- Start the engine.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition? | - | Go to Step 2 | Go to Step 14 |
| 14 | Check if any additional DTCs are set. Are there any DTCs that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) P2294
DTC Description
Note : The symptom byte may not be displayed on a scan tool.
DTC P2294 (01): Fuel Pressure Regulator Solenoid 2 Control Circuit (Short to Battery)
DTC P2294 (02): Fuel Pressure Regulator Solenoid 2 Control Circuit (Short to Ground)
DTC P2294 (04): Fuel Pressure Regulator Solenoid 2 Control Circuit (Open Circuit)
DTC P2294 (54): Fuel Pressure Regulator Solenoid 2 Control Circuit (Temperature High)
Circuit/System Description
The fuel rail pressure (FRP) regulator is actuated via a current. Due to the high self dynamic, the fuel rail pressure (FRP) regulator solenoid valve is operated with a high PWM frequency (>1kHz). Since the coil of the fuel rail pressure (FRP) regulator experiences a temperature based change in resistance, the present coil current is measured and the change in resistance counteracted by current control.
This is accomplished by so-called fuel rail pressure (FRP) regulator component driver. The following sub-tasks are carried out in this component driver:
- Sensing the actual current of the fuel rail pressure (FRP) regulator and analog channel monitoring
- Current regulation
- Actuator voltage output as PWM to the fuel rail pressure (FRP) regulator and error monitoring power stage
The engine control module (ECM) supplies power and ground to the fuel rail pressure (FRP) regulator solenoid valve. The ECM monitors current on the circuits to detect a failure.
Conditions for Running the DTC
P2294(01) and P2294(54)
- Ignition switch is ON
- Fuel pressure regulator solenoid is actuated
- Battery voltage is less than 16.5V
P2294(02) and P2294(04)
- Ignition switch is ON
- Fuel pressure regulator solenoid is switched off
- Battery voltage is less than 16.5V
Conditions for Setting the DTC
P2294(01)
- A short to battery condition exists in the fuel pressure regulator solenoid control circuit
P2294(02)
- A short to ground condition exists in the fuel pressure regulator solenoid control circuit
P2294(04)
- An open condition exists in the fuel pressure regulator solenoid control circuit
P2294(54)
- A high temperature condition exists in the fuel pressure regulator solenoid control circuit
Action Taken When the DTC Sets
Conditions for Clearing the MIL/DTC
Test Description
The numbers below refer to the step numbers on the diagnostic table.
- This step tests for battery voltage through the ECM to the fuel rail pressure (FRP) regulator.
- This step tests for an open control circuit between the ECM and the fuel rail pressure (FRP) regulator.
- This code can be set by voltage being applied between the ECM and fuel rail pressure (FRP) regulator on fuel rail pressure (FRP) regulator control circuit.
DTC P2294
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | Attempt to start the engine. Does the engine start? | - | Go to Step 4 | Go to Step 3 |
| 3 | - Turn OFF the ignition.
- Disconnect the engine control module (ECM) connectors.
- Disconnect the fuel rail pressure (FRP) regulator solenoid connector.
- Measure the resistance from the control circuit of the fuel rail pressure (FRP) regulator solenoid to ground with a DMM.
Does the resistance measure at the specified value? | ∞ | Go to Step 12 | Go to Step 9 |
| 4 | - Turn OFF the ignition.
- Disconnect the fuel rail pressure (FRP) regulator solenoid harness connector.
- Turn ON the ignition, with the engine OFF.
- Probe the voltage supply circuit of the fuel rail pressure (FRP) regulator solenoid with a test Lamp connected to a good ground.
Does the test lamp illuminate? | - | Go to Step 5 | Go to Step 7 |
| 5 | - Turn OFF the ignition.
- Verify the fuel rail pressure (FRP) regulator solenoid harness connector is disconnected.
- Turn ON the ignition, with the engine OFF.
- Probe the control circuit of the fuel rail pressure (FRP) regulator solenoid with a test lamp connected to battery voltage.
Does the test lamp illuminate? | - | Go to Step 10 | Go to Step 6 |
| 6 | - Disconnect the ECM connector containing the fuel rail pressure (FRP) regulator solenoid control circuit.
- Turn ON the ignition, with the engine OFF.
- Measure the voltage from the fuel rail pressure (FRP) regulator solenoid control circuit to a good ground with a DMM.
Does the voltage measure the specified value? | 0 V | Go to Step 13 | Go to Step 8 |
| 7 | - Test for an open in the voltage supply circuit between the ECM and the fuel rail pressure (FRP) regulator.
- If a condition is found, repair as necessary.
Did you find and correct the condition? | - | Go to Step 16 | Go to Step 14 |
| 8 | Repair the short to voltage in the control circuit between the ECM and the fuel rail pressure (FRP) regulator solenoid. Did you complete the repair? | - | Go to Step 16 | - |
| 9 | Test for a short to ground in the control circuit between the ECM and the fuel rail pressure (FRP) regulator solenoid. Did you find and correct the condition? | - | Go to Step 16 | Go to Step 15 |
| 10 | Test the ignition voltage, fuel rail pressure (FRP) regulator solenoid control, and fuel rail pressure (FRP) regulator solenoid supply voltage circuits for high resistance. Did you find and correct the condition? | - | Go to Step 16 | Go to Step 11 |
| 11 | Test for an intermittent and for a poor connection at the fuel rail pressure (FRP) regulator solenoid. Did you find and correct the condition? | - | Go to Step 16 | Go to Step 12 |
| 12 | Replace the fuel rail pressure (FRP) regulator. Did you complete the replacement? | - | Go to Step 16 | - |
| 13 | Test for an open in the control circuit between the ECM and the fuel rail pressure (FRP) regulator solenoid. Did you find and correct the condition? | - | Go to Step 16 | Go to Step 14 |
| 14 | - Inspect for poor connections at the ECM.
- Repair the wiring, as necessary.
Did you find and correct the condition? | - | Go to Step 16 | Go to Step 15 |
| 15 | Replace the ECM. Did you complete the replacement? | - | Go to Step 16 | - |
| 16 | - Clear the DTCs with the scan tool.
- Turn OFF the ignition for 30 seconds.
- Start the engine.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition? | - | Go to Step 2 | Go to Step 17 |
| 17 | Check if any additional DTCs are set. Are there any DTCs that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) P2510
DTC Description
Note : The symptom byte may not be displayed on a scan tool.
DTC P2510 (58): Engine Controls Ignition Relay Feedback Performance (Incorrect Reaction After Event)
DTC P2510 (59): Engine Controls Ignition Relay Feedback Performance (Circuit/Component Protection Time-Out)
Circuit/System Description
When the ignition is switched ON, the main relay is closed via the hardware. This switches the ECM ON. When the ignition is switched OFF, the main relay remains closed at first to make a control unit afterrun possible. After the afterrun is completed, the main relay is opened by a corresponding control via the software.
If the main relay is not switched off after the power down time of the control units or the main relay is shut off too early in the power down time of the control unit, a DTC will set.
Conditions for Running the DTC
Conditions for Setting the DTC
P2510(58)
- The ECM detects that the main relay opens too early
P2510(59)
- The ECM detects that the main relay does not open in time
Action Taken When the DTC Sets
Conditions for Clearing the MIL/DTC
Diagnostic Aids
- If an intermittent condition is suspected refer to "Intermittent Conditions".
- The switched voltage supply circuit of the main relay is electrically connected to the following components. Conditions in these circuits can cause the DTC to be set:
- Fuel filter heater relay
- Glow plug control circuit
- Throttle plate actuator
- Boost pressure actuator
- Camshaft position (CMP) sensor
- Exhaust gas recirculation (EGR) valve solenoid
- Cooling fan relays
- A/C compressor relay
DTC P2510
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | - Turn the ignition ON.
- Observe the scan tool DTC information.
Are any other DTCs set? | - | Go to applicable DTC table | Go to Step 3 |
| 3 | - Turn the ignition OFF.
- Remove the main relay.
- Turn the ignition ON.
- Using a DMM, measure the voltage between the main relay control circuit and a good ground.
Is the voltage less than the specified value? | 0.3 V | Go to Step 4 | Go to Step 8 |
| 4 | - Make sure the ignition is ON.
- Using a DMM, measure the voltage between the switched voltage supply circuit of the main relay and a good ground.
Is the voltage less than the specified value? | 0.3 V | Go to Step 5 | Go to Step 6 |
| 5 | - Turn the ignition OFF.
- Disconnect the wiring harness connector from the ECM.
- Using a DMM, measure the resistance between the main relay control circuit and a good ground.
Is the resistance greater than the specified value? | 500 Kohm | Go to Step 7 | Go to Step 9 |
| 6 | Check the switched voltage supply circuit of the main relay for the following conditions: - Short to voltage
- Short to ground
Did you find and correct the condition? | - | Go to Step 11 | Go to Step 10 |
| 7 | Check the main relay control circuit for a high resistance. Did you find and correct the condition? | - | Go to Step 11 | Go to Step 10 |
| 8 | Check the main relay control circuit for a short to voltage. Did you find and correct the condition? | - | Go to Step 11 | Go to Step 10 |
| 9 | Check the main relay control circuit for a short to ground. Did you find and correct the condition? | - | Go to Step 11 | Go to Step 10 |
| 10 | Replace the ECM. Did you complete the replacement? | - | Go to Step 11 | - |
| 11 | - Clear the DTCs with a scan tool.
- Turn OFF the ignition for 30 seconds.
- Start the engine.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition? | - | Go to Step 2 | Go to Step 12 |
| 12 | Check if any additional DTCs are set. Are there any DTCs that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) P2544
DTC Description
Note : The symptom byte may not be displayed on a scan tool.
DTC P2544 (72): Transmission Torque Request Circuit (Alive Counter Incorrect/Not Updated)
DTC P2544 (74): Transmission Torque Request Circuit (Value of Signal Protection Calculation Incorrect)
Circuit/System Description
To improve shift feel, the transmission control module (TCM) may request that the engine control module (ECM) reduce engine torque during shift events. When such a request is received, the ECM responds by retarding the injection timing and notifying the TCM that the request has succeeded. If the ECM is unable to comply with the request, the ECM sends the TCM a message that the request has failed.
The torque reduction request is sent to the ECM through a communication network called the GMLAN. When the TCM receives a torque reduction failure message from the ECM, the DTC will set.
Conditions for Running the DTC
Conditions for Setting the DTC
P2544(72)
- The ECM detects that the total number of rolling count error is greater than 3
P2544(74)
- The ECM detects that the total number of protection value error is greater than 5
Action Taken When the DTC Sets
- DTC P2544 is type Cnl DTC.
Conditions for Clearing the MIL/DTC
- DTC P2544 is type Cnl DTC.
DTC P2544
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | Using a scan tool, observe the DTC information. Are any other DTCs set other than P2544? | - | Go to applicable DTC table | Go to Step 3 |
| 3 | - Clear the DTC.
- Turn the ignition OFF for at least 30 seconds.
- Operate the vehicle within the Conditions for Running the DTC.
Did DTC P2544 reset? | - | Go to Step 4 | |
| 4 | Replace the TCM. Did you complete the replacement? | - | Go to Step 5 | - |
| 5 | - Use the scan tool in order to clear the DTCs.
- Operate the vehicle within the Conditions for Running the DTC.
Does the DTC reset? | - | Go to Step 2 | Go to Step 6 |
| 6 | Check if any additional DTCs are set. Are there any DTCs that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) P2687
DTC Description
Note : The symptom byte may not be displayed on a scan tool.
DTC P2687 (01): Fuel Heater Relay Control Circuit (Short to Battery)
DTC P2687 (02): Fuel Heater Relay Control Circuit (Short to Ground)
DTC P2687 (04): Fuel Heater Relay Control Circuit (Open Circuit)
DTC P2687 (54): Fuel Heater Relay Control Circuit (Temperature High)
Circuit/System Description
The engine control module (ECM) controls the voltage supply to the fuel heater by grounding the fuel heater relay control circuit with an internal solid state device called a driver. When the ECM is commanding a fuel heater relay ON, the voltage of the control circuit should be low, near 0 volts. When the ECM is commanding a fuel heater relay OFF, the voltage potential of the control circuit should be high, near battery voltage. If the ECM detects an improper circuit condition, a DTC will set.
Conditions for Running the DTC
- Ignition switch is ON
- Battery voltage is less than 16.5V
Conditions for Setting the DTC
P2687(01)
- A short to battery condition exists in the fuel heater control circuit
P2687(02)
- A short to ground condition exists in the fuel heater control circuit
P2687(04)
- An open condition exists in the fuel heater control circuit
P2687(54)
- A high temperature condition exists in the fuel heater control circuit
Action Taken When the DTC Sets
- DTC P2687 is type Cnl DTC.
Conditions for Clearing the MIL/DTC
- DTC P2687 is type Cnl DTC.
Diagnostic Aids
- For an intermittent fault condition, refer to "Intermittent Conditions"
- Since fault condition in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic procedure for shorted terminals or poor wiring connection before replacing any component.
DTC P2687
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | - Disconnect the wiring harness connector from the PTC heater.
- Turn ON the ignition, with the engine OFF.
- Probe the voltage supply circuit of the PTC heater with a test lamp connected to a good ground.
- Command the PTC heater relay ON and OFF with a scan tool.
Does the test lamp turn ON and OFF with each command? | - | Go to Step 3 | Go to Step 4 |
| 3 | - Observe the Freeze Frame/Failure Records for this DTC.
- Turn OFF the ignition for 30 seconds.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition? | - | Go to Step 4 | Go to Diagnostic Aids |
| 4 | - Turn OFF the ignition.
- Disconnect the PTC heater relay.
- Turn ON the ignition, with the engine OFF.
- Probe the control circuit of the PTC heater relay with a test lamp connected to battery voltage.
- Command the PTC heater ON and OFF with a scan tool.
Does the test lamp turn ON and OFF when commanded? | - | Go to Step 5 | Go to Step 6 |
| 5 | - Connect a test lamp between the control circuit and voltage supply circuit of the PTC heater relay.
- Command the PTC heater ON and OFF with a scan tool.
Does the test lamp turn ON and OFF when commanded? | - | Go to Step 7 | Go to Step 9 |
| 6 | Test the control circuit of the PTC heater relay for followings: - An open or a high resistance
- A short to voltage
- A short to ground
Did you find and correct the condition? | - | Go to Step 12 | Go to Step 8 |
| 7 | Test for an intermittent and for a poor connection at the PTC heater relay. Did you find and correct the condition? | - | Go to Step 12 | Go to Step 10 |
| 8 | Test for an intermittent and for a poor connection at the engine control module (ECM). Did you find and correct the condition? | - | Go to Step 12 | Go to Step 11 |
| 9 | Repair the open, high resistance, or short to ground in the voltage supply circuit of the PTC heater relay. Did you complete the repair? | - | Go to Step 12 | - |
| 10 | Replace the PTC heater relay. Did you complete the replacement? | - | Go to Step 12 | - |
| 11 | Replace the ECM. Did you complete the replacement? | - | Go to Step 12 | - |
| 12 | - Clear the DTCs with a scan tool.
- Turn OFF the ignition for 30 seconds.
- Start the engine.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition? | - | Go to Step 2 | Go to Step 13 |
| 13 | Check if any additional DTCs are set. Are there any DTCs that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) U0073
DTC Description
Note : The symptom byte may not be displayed on a scan tool.
DTC U0073 (00): Control Module Communication Bus Off
Circuit/System Description
The GMLAN serial data circuits are controller area network (CAN) high speed serial data buses used to communicate information between the control modules. Typical data transmission speeds must be high enough to ensure that a required real-time response is maintained. On this vehicle there are 2 utterly different types of GMLAN serial data circuits, the High speed 2-wire circuit and Low speed single wire circuit. The GMLAN serial data circuits also communicate directly to the data link connector (DLC). Messages are interpreted by the externally connected CANdi module which acts as a transceiver for the scan tool.
Conditions for Running the DTC
Conditions for Setting the DTC
- CAN controller is in bus off state, OR
- CAN controller has DLL overrun error
Action Taken When the DTC Sets
Conditions for Clearing the MIL/DTC
Diagnostic Aids
- This DTC cannot be retrieved with a current status. Diagnosis of a current DTC is accomplished via the symptom, “Scan Tool Does Not Communicate with High Speed GMLAN Device”. Refer to “Data Link References” for the correct procedure for the specific module(s).
- An intermittent condition is likely to be caused by a short on the GMLAN serial data circuits. Use the “Scan Tool Does Not Communicate with High Speed GMLAN Device” procedure in order to isolate an intermittent condition. Refer to “Data Link References” for the correct procedure for the specific modules.
DTC U0073
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | Refer to “Scan Tool Does Not Communicate with High Speed GMLAN Device” | - | - | - |
Diagnostic Trouble Code (DTC) U0101, U0102, U0104, U0121, U0140
DTC Description
Note : The symptom byte may not be displayed on a scan tool.
DTC U0101 (00): Lost Communication with TCM
DTC U0101 (46): Lost Communication with TCM (Vehicle Configuration Not Programmed)
DTC U0102 (00): Lost Communication with Transfer Case Control Module
DTC U0102 (46): Lost Communication with Transfer Case Control Module (Vehicle Configuration Not Programmed)
DTC U0104 (00): Lost Communication With Cruise Control Module
DTC U0121 (00): Lost Communication With Anti-Lock Brake System (ABS) Control Module
DTC U0121 (71): Lost Communication With Anti-Lock Brake System (ABS) Control Module (Invalid Serial Data Received)
DTC U0140 (00): Lost Communication With Body Control Module
DTC U0140 (46): Lost Communication With Body Control Module (Vehicle Configuration Not Programmed)
Circuit/System Description
Modules connected to the high and low speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.
Conditions for Running the DTC
Conditions for Setting the DTC
U0101(00), U0102(00), U0104(00), U0121(00), and U0140(00)
- No signal from corresponding CAN node
U0101(46)
- A key message from TCM node is not received
U0102(46)
- A key message from TCCM node is not received
U0121(71)
- The ECM detects that the validity information from both the left and the right driven wheels is received as invalid
U0140(46)
- A key message from BCM node is not received
Action Taken When the DTC Sets
- DTC U0101(00), U0102, U0104, U0121, and U0140 are type Cnl DTCs.
- DTC U0101(46) is type E DTC.
Conditions for Clearing the MIL/DTC
- DTC U0101(00), U0102, U0104, U0121, and U0140 are type Cnl DTCs.
- DTC U0101(46) is type E DTC.
Diagnostic Aids
- A poor connection at the inoperative module may cause this code to set.
- An improperly powered module may cause this code to set.
- If there are multiple non-communicating modules choose the one closest to the data link connector (DLC). Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module. This diagnostic can be used for any module that should communicate with high or low speed GMLAN serial data providing the vehicle is equipped with the option that uses that module.
DTC U0101, U0102, U0104, U0121, U0140
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | Test the following circuits of the module that is not communicating for an open or a short to ground: - The battery positive voltage input circuits
- The battery positive voltage output circuits
- The ignition voltage input circuits
- The ignition voltage output circuits
- The switched battery positive voltage circuits
Did you find and correct the condition? | - | Go to Step 7 | Go to Step 3 |
| 3 | - Turn OFF the ignition.
- Test the ground circuits of the module that is not communicating for an open.
Did you find and correct the condition? | - | Go to Step 7 | Go to Step 4 |
| 4 | Test the high speed GMLAN serial data circuits of the module that is not communicating for an open. Did you find and correct the condition? | - | Go to Step 7 | Go to Step 5 |
| 5 | Inspect the harness connectors of the module that is not communicating for poor connections and terminal tension at the following circuits: - The battery positive voltage input circuits
- The battery positive voltage output circuits
- The ignition voltage input circuits
- The ignition voltage output circuits
- The switched battery positive voltage supply circuits
- The ground circuits
- The high speed GMLAN serial data circuits
Did you find and correct the condition? | - | Go to Step 7 | Go to Step 6 |
| 6 | Replace the module that is not communicating. Did you complete the replacement? | - | Go to Step 7 | - |
| 7 | - Clear the DTCs with a scan tool.
- Turn OFF the ignition for 30 seconds.
- Start the engine.
- Operate the vehicle within the Conditions for Setting the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition? | - | Go to Step 2 | Go to Step 8 |
| 8 | Check if any additional DTCs are set. Are there any DTCs that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) U2101
DTC Description
Note : The symptom byte may not be displayed on a scan tool.
DTC U2101 (45): Maximum List of Control Modules Not Programmed (Variant Not Programmed)
Circuit/System Description
Modules connected to the high and low speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.
Conditions for Running the DTC
Conditions for Setting the DTC
- Variant coding is not programmed in EEPROM
Action Taken When the DTC Sets
- DTC U2101 is type Cnl DTC.
Conditions for Clearing the MIL/DTC
- DTC U2101 is type Cnl DTC.
DTC U2101
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | - Install the scan tool.
- Turn the ignition ON, with the engine OFF.
- Observe the Subnet configuration parameter with a scan tool.
Is the configuration same with the actual vehicle configuration? | - | Go to Step 4 | Go to Step 3 |
| 3 | Perform the vehicle configuration programming using a scan tool. Did you complete the setup? | - | Go to Step 4 | - |
| 4 | - Use the scan tool in order to clear the DTCs.
- Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset? | - | Go to Step 5 | Go to Step 7 |
| 5 | Replace the ECM. Did you complete the replacement? | - | Go to Step 6 | - |
| 6 | - Use the scan tool in order to clear the DTCs.
- Operate the vehicle within Conditions for Running the DTCs as specified in the supporting text.
Does the DTC reset? | - | Go to Step 2 | Go to Step 7 |
| 7 | Check if any additional DTCs are set. Are there any DTCs that have not been diagnosed? | - | Go to applicable DTC table | System OK |
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