Diagnostic Trouble Code (DTC) P0621
Generator L - Terminal Circuit
Circuit Description
The engine control module (ECM) applies a signal voltage to the Generator L terminal circuit to control the load of the generator on the engine. A Generator L terminal circuit DTC sets if the ECM detects the Generator L circuit voltage is outside the specified range for a predetermined set of parameters.
Conditions for Running the DTC
Conditions for Setting the DTC
- The ECM detects a low signal voltage on the generator L terminal.
Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will be illuminated after 3 valid driving cycles.
- The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.
Conditions for Clearing the MIL/DTC
- The MIL will turn off after three or four consecutive driving cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
- Disconnecting the ECM battery feed for 10 seconds.
DTC P0621 - Generator L - Terminal Circuit
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | - Switch off the ignition for 30 seconds.
- Operate the vehicle within the conditions for running the DTC.
- Using the Scan Tool, select the DTC display function.
Did the DTC P0621 fail this ignition? | - | Go to Step 3 | - |
| 3 | Test the charging system for any fault condition that may cause incorrect generator operation. Did you find and correct the condition? | - | Go to Step 6 | Go to Step 4 |
| 4 | Test the generator L signal circuit for a high resistance, open circuit, or short to ground fault condition. Did you find and correct the condition? | - | Go to Step 6 | Go to Step 5 |
| 5 | Replace the ECM. Did you complete the replacement? | - | Go to Step 6 | - |
| 6 | - 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 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 |
Diagnostic Trouble Code (DTC) P0627
Fuel Pump Relay Control Circuit Open
Circuit Description
When the ignition switch is turned ON, the ECM will activate the fuel pump relay and run the in-tank fuel pump.
The fuel pump will operate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.
Conditions for Running the DTC
Conditions for Setting the DTC
- Controler IC check the current and voltage of the output stage.
Action Taken When the DTC Sets
- The Service Vehicle Soon (SVS) Lamp will be illuminated as soon as the error occurs.
- The ECM will record operating conditions at the time the disgnostic fails. This information will be stored in Failure Records buffers.
- A history DTC is stored.
Conditions for Clearing the MIL/DTC
- The SVS lamp will turn off after current driving cycle in which the disgnostic runs without a fault.
- A history DTC will clear after 20 consecutive warm-up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
- Disconnecting the ECM battery feed for 10 secponds.
Diagnostic Aids
An Intermittent problem may be caused by a poor connection, rubbed through wire insulation, or wire that is broken inside the insulation.
Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for the following conditions.
- Backed-out terminals
- Improper mating
- Broken locks
- Improperly formed
- Damaged terminals
- Poor terminals to wire connection
- Physical damage to the wiring harness
DTC P0627 - Fuel Pump Relay Control Circuit Open
| Step | Action | Value(s) | Yes | No |
| 1 | Perform the Diagnostic System Check. Is the system check complete? | - | Go to Step 2 | |
| 2 | - Turn the ignition switch to LOCK for 10 seconds.
- Turn the ignition switch to ON.
- Listen for in-tank fuel pump operation.
Does the fuel pump operate? | 2 seconds | | Go to Step 3 |
| 3 | - Turn the ignition switch to ON.
- Disconnect the fuel pump relay.
- Connect a test light between the fuel pump relay connector terminal 86 and ground.
- Turn the ignition switch to ON.
Is the test light ON? | - | Go to Step 4 | Go to Step 10 |
| 4 | - Turn the ignition switch to ON.
- Disconnect the fuel pump relay.
- Connect a test light between the fuel pump relay connector terminal 85 and B+.
- Turn the ignition switch to ON.
Is the test light ON? | - | Go to Step 5 | Go to Step 9 |
| 5 | - Turn the ignition switch to LOCK.
- Connect a test light between the fuel pump relay connector terminal 30 and ground.
Is the test light ON? | - | Go to Step 6 | Go to Step 8 |
| 6 | Check for an open in the wire between the fuel pump relay connector terminal 87 and fuel pump connector. Is the problem found? | - | Go to Step 7 | Go to Step 8 |
| 7 | - Repair the wire between the fuel pump relay connector terminal 87 and fuel pump connector terminal 4.
- Install the fuel pump relay.
- Turn the engine OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | Go to Step 14 | - |
| 8 | - Replace the fuel pump relay.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | Go to Step 14 | Go to Step 9 |
| 9 | Check for an open wire between the fuel pump relay connector terminal 85 and the ignition after key ON(IGN 1). Is the problem found? | - | Go to Step 11 | Go to Step 10 |
| 10 | Check for an open wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51. Is the problem found? | - | Go to Step 12 | Go to Step 13 |
| 11 | - Repair the wire between the fuel pump relay connector terminal 85 and the ignition key ON (IGN1).
- Install the fuel pump relay.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | System OK | Go to Step 13 |
| 12 | - Repair the wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51.
- Install the fuel pump relay.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | System OK | Go to Step 13 |
| 13 | - Replace the ECM.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | System OK | Go to Step 14 |
| 14 | - Using the scan tool, clear the DTCs.
- Start the engine and idle at normal operating temperature.
- Operate the vehicle within the conditions for setting this DTC ad specified in the supporting text.
Does the scan tool indicate that this diagnostic has run and passed? | - | Go to Step 15 | Go to Step 2 |
| 15 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) P0628
Fuel Pump Relay Control Circuit Low Voltage
Circuit Description
When the ignition switch is turned ON, the ECM will activate the fuel pump relay and run the in-tank fuel pump.
The fuel pump will operate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.
Conditions for Running the DTC
Conditions for Setting the DTC
- Controler IC check the current and voltage of the output stage.
Action Taken When the DTC Sets
- The Service Vehicle Soon (SVS) Lamp will be illuminated as soon as the error occurs.
- The ECM will record operating conditions at the time the disgnostic fails. This information will be stored in Failure Records buffers.
- A history DTC is stored.
Conditions for Clearing the MIL/DTC
- The SVS lamp will turn off after current driving cycle in which the disgnostic runs without a fault.
- A history DTC will clear after 20 consecutive warm-up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
- Disconnecting the ECM battery feed for 10 secponds.
Diagnostic Aids
An Intermittent problem may be caused by a poor connection, rubbed through wire insulation, or wire that is broken inside the insulation.
Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for the following conditions.
- Backed-out terminals
- Improper mating
- Broken locks
- Improperly formed
- Damaged terminals
- Poor terminals to wire connection
- Physical damage to the wiring harness
DTC P0628 - Fuel Pump Relay Control Circuit Low Voltage
| Step | Action | Value(s) | Yes | No |
| 1 | Perform the Diagnostic System Check. Is the system check complete? | - | Go to Step 2 | |
| 2 | - Turn the ignition switch to LOCK for 10 seconds.
- Turn the ignition switch to ON.
- Listen for in-tank fuel pump operation.
Does the fuel pump operate? | 2 seconds | | Go to Step 3 |
| 3 | - Turn the ignition switch to ON.
- Disconnect the fuel pump relay.
- Connect a test light between the fuel pump relay connector terminal 86 and ground.
- Turn the ignition switch to ON.
Is the test light ON? | - | Go to Step 4 | Go to Step 10 |
| 4 | - Turn the ignition switch to ON.
- Disconnect the fuel pump relay.
- Connect a test light between the fuel pump relay connector terminal 85 and B+.
- Turn the ignition switch to ON.
Is the test light ON? | - | Go to Step 5 | Go to Step 9 |
| 5 | - Turn the ignition switch to LOCK.
- Connect a test light between the fuel pump relay connector terminal 30 and ground.
Is the test light ON? | - | Go to Step 6 | Go to Step 8 |
| 6 | Check for a short to ground in the wire between the fuel pump relay connector terminal 87 and fuel pump connector. Is the problem found? | - | Go to Step 7 | Go to Step 8 |
| 7 | - Repair the wire between the fuel pump relay connector terminal 87 and fuel pump connector terminal 4.
- Install the fuel pump relay.
- Turn the engine OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | Go to Step 14 | - |
| 8 | - Replace the fuel pump relay.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | Go to Step 14 | Go to Step 9 |
| 9 | Check for a short to ground wire between the fuel pump relay connector terminal 85 and the ignition after key ON(IGN 1). Is the problem found? | - | Go to Step 11 | Go to Step 10 |
| 10 | Check for a short to ground wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51. Is the problem found? | - | Go to Step 12 | Go to Step 13 |
| 11 | - Repair the wire between the fuel pump relay connector terminal 85 and the ignition key ON (IGN1).
- Install the fuel pump relay.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | System OK | Go to Step 13 |
| 12 | - Repair the wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51.
- Install the fuel pump relay.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | System OK | Go to Step 13 |
| 13 | - Replace the ECM.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | System OK | Go to Step 14 |
| 14 | - Using the scan tool, clear the DTCs.
- Start the engine and idle at normal operating temperature.
- Operate the vehicle within the conditions for setting this DTC ad specified in the supporting text.
Does the scan tool indicate that this diagnostic has run and passed? | - | Go to Step 15 | Go to Step 2 |
| 15 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) P0629
Fuel Pump Relay Control Circuit High Voltage
Circuit Description
When the ignition switch is turned ON, the ECM will activate the fuel pump relay and run the in-tank fuel pump.
The fuel pump will operate as long as the engine is cranking or running and the ECM is receiving ignition reference pulses.
Conditions for Running the DTC
Conditions for Setting the DTC
- Controler IC check the current and voltage of the output stage.
Action Taken When the DTC Sets
- The Service Vehicle Soon (SVS) Lamp will be illuminated as soon as the error occurs.
- The ECM will record operating conditions at the time the disgnostic fails. This information will be stored in Failure Records buffers.
- A history DTC is stored.
Conditions for Clearing the MIL/DTC
- The SVS lamp will turn off after current driving cycle in which the disgnostic runs without a fault.
- A history DTC will clear after 20 consecutive warm-up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
- Disconnecting the ECM battery feed for 10 secponds.
Diagnostic Aids
An Intermittent problem may be caused by a poor connection, rubbed through wire insulation, or wire that is broken inside the insulation.
Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for the following conditions.
- Backed-out terminals
- Improper mating
- Broken locks
- Improperly formed
- Damaged terminals
- Poor terminals to wire connection
- Physical damage to the wiring harness
DTC P0629 - Fuel Pump Relay Control Circuit High Voltage
| Step | Action | Value(s) | Yes | No |
| 1 | Perform the Diagnostic System Check. Is the system check complete? | - | Go to Step 2 | |
| 2 | - Turn the ignition switch to LOCK for 10 seconds.
- Turn the ignition switch to ON.
- Listen for in-tank fuel pump operation.
Does the fuel pump operate? | 2 seconds | | Go to Step 3 |
| 3 | Check for short to battery voltage or low voltage in the wire between the fuel pump relay connector terminal 87 and fuel pump connector 4. Is the problem found? | - | Go to Step 7 | Go to Step 5 |
| 4 | - Repair the wire between the fuel pump relay connector terminal 87 and fuel pump connector terminal 4.
- Install the fuel pump relay.
- Turn the engine OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | Go to Step 11 | - |
| 5 | - Replace the fuel pump relay.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | Go to Step 11 | Go to Step 6 |
| 6 | Check for short to battery voltage wire between the fuel pump relay connector terminal 85 and the ignition after key ON(IGN 1). Is the problem found? | - | Go to Step 8 | Go to Step 7 |
| 7 | Check for an open wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51. Is the problem found? | - | Go to Step 9 | Go to Step 10 |
| 8 | - Repair the wire between the fuel pump relay connector terminal 85 and the ignition key ON (IGN1).
- Install the fuel pump relay.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | System OK | Go to Step 10 |
| 9 | - Repair the wire between the fuel pump relay connector terminal 86 and the ECM connector J1 terminal 51.
- Install the fuel pump relay.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | System OK | Go to Step 10 |
| 10 | - Replace the ECM.
- Turn the ignition OFF for 10 seconds.
- Clear any DTCs from ECM.
- Turn the ignition switch to ON.
Does the fuel pump operate? | 2 seconds | System OK | Go to Step 11 |
| 11 | - Using the scan tool, clear the DTCs.
- Start the engine and idle at normal operating temperature.
- Operate the vehicle within the conditions for setting this DTC ad specified in the supporting text.
Does the scan tool indicate that this diagnostic has run and passed? | - | Go to Step 12 | Go to Step 2 |
| 12 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) P0630
Vin not Programmed or Mismatched - Engine Control Module (ECM)
Circuit Description
The engine control module (ECM) stores the vehicle identification number (VIN). If there is not a VIN stored in the ECM, this DTC sets.
Conditions for Running the DTC
Conditions for Setting the DTC
- The ECM detects that VIN information is not stored.
Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will be illuminated as soon as the error occurs.
- The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.
Conditions for Clearing the MIL/DTC
- The MIL will turn off after three or four consecutive driving cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
- Disconnecting the ECM battery feed for 10 seconds.
DTC P0630 - Vin not Programmed or Mismatched - Engine Control Module (ECM)
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | - Install a scan tool.
- Turn the ignition ON, with the engine OFF.
- With the scan tool, observe the Vehicle Identification Number (VIN) Information parameter.
Is the VIN Information stored? | - | Go to Step 3 | Go to Step 4 |
| 3 | - Clear the DTCs with a scan tool.
- Turn OFF the ignition for 30 seconds.
- Turn ON the ignition.
- Operate the vehicle within the Conditions for Setting the DTC.
Does the DTC run and pass? | - | Go to Step 7 | Go to Step 5 |
| 4 | Using the scan tool, write the VIN information on the ECM. Did you complete VIN writing? | - | Go to Step 6 | - |
| 5 | Replace the ECM. Did you complete the replacement? | - | Go to Step 6 | - |
| 6 | - Clear the DTCs with a scan tool.
- Turn OFF the ignition for 30 seconds.
- Turn ON the ignition.
- Operate the vehicle within the Conditions for Setting the DTC.
Does the DTC run and pass? | - | Go to Step 7 | Go to Step 2 |
| 7 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) P0633
Immobilizer Key not Programmed
Circuit Description
When learning the fuel enable password, as well as the challenge and response sequence, the engine control module (ECM) is placed in learn mode. DTC P0633 will set automatically as an indicator that the system is in learn mode and not as a fault indicator. Once the password and challenge/response are learned, learn mode will be exited and the DTC cleared. If the ECM does not exit learn mode, P0633 will remain current and indicate a fault.
Conditions for Running the DTC
- Theft deterrent system is activated.
Conditions for Setting the DTC
- The ECM secret keys are not programmed,
or
- The ECM enters learn mode.
Action Taken When the DTC Sets
- The Service Vehicle Soon (SVS) Lamp will be illuminated as soon as the error occurs.
- The ECM will record operating conditions at the time the disgnostic fails. This information will be stored in Failure Records buffers.
- A history DTC is stored.
Conditions for Clearing the MIL/DTC
- The SVS lamp will turn off after current driving cycle in which the disgnostic runs without a fault.
- A history DTC will clear after 20 consecutive warm-up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
- Disconnecting the ECM battery feed for 10 secponds.
Diagnostic Aids
The "key" referenced in the DTC descriptor does not refer to the vehicle key. In this case, "key" is referring to the challenge response.
DTC P0633 - Immobilizer Key not Programmed
| Step | Action | Value(s) | Yes | No |
| 1 | Perform the Diagnostic System Check. Is the system check complete? | - | Go to Step 2 | |
| 2 | - Turn the ignition switch to LOCK.
- Install a scan tool to the data link connector (DLC).
- Turn the ignition switch to ON.
- Check if other immobilizer related DTCs are set.
Are any DTCs displayed? | - | Go to Applicable DTC table | Go to Step 3 |
| 3 | Does the DTC run and pass? | - | Go to Step 5 | Go to Step 4 |
| 4 | Replace the ECM. Is the replace complete? | - | Go to Step 5 | - |
| 5 | - 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 2 |
| 6 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | - | Go to applicable DTC table | System OK |
Diagnostic Trouble Code (DTC) P0638
Throttle Actuator Control (TAC) Command Performance
Circuit Description
The engine control module (ECM) controls the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control (TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors the throttle position (TP) sensors 1 and 2 to determine the actual throttle valve position.
Conditions for Running the DTC
Conditions for Setting the DTC
- Sum of the PID components are more than 80 %.
Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will be illuminated as soon as the error occurs.
- The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.
Conditions for Clearing the MIL/DTC
- The MIL will turn off after three or four consecutive driving cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
- Disconnecting the ECM battery feed for 10 seconds.
Diagnostic Aids
- Inspect for a condition in which the throttle valve may have been held open. For example, ice may have formed in the throttle bore causing the throttle valve not to close. Observe the Freeze Frame/Failure Records.
- The throttle valve is spring loaded to a slightly open position. The throttle valve should be open approximately 3-5 percent. This is referred to as the rest position.
- The throttle valve should not be completely closed or open any more than a specified amount.
- The throttle valve should move open and to the closed position without binding under the normal spring pressure.
- The throttle should NOT be free to move open or closed WITHOUT spring pressure.
- For an intermittent condition, refer to "Intermittents".
DTC P0638 - Throttle Actuator Control (TAC) Command Performance
| Step | Action | Value(s) | Yes | No |
| 1 | Did you perform the Diagnostic System Check? | - | Go to Step 2 | |
| 2 | - Turn On the ignition, with the engine OFF.
- Clear the DTCs with a scan tool.
- Start the engine.
- Perform the following tests:
- Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times.
- Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times.
- Observe the DTC information with a scan tool.
Did DTC P0121, P0122, P0123, P0221, P0222, or P0223 fail this ignition? | - | Go to applicable DTC table | Go to Step 3 |
| 3 | Did DTC P0638, and/or P2119 fail this ignition? | - | Go to Step 5 | Go to Step 4 |
| 4 | - Observe the Freeze Frame/Failure Records for this DTC.
- 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 5 | |
| 5 | - Turn OFF the engine.
- Turn ON the ignition, with the engine OFF.
- Observe the TP sensor 1 voltage parameter with a scan tool.
Is the voltage within the specified range? | 0.40-0.80 V | Go to Step 6 | |
| 6 | Observe the TP sensor 2 voltage parameter with a scan tool. Is the voltage within the specified range? | 4.7-4.1 V | Go to Step 7 | |
| 7 | - Disconnect the throttle body harness connector.
- Turn ON the ignition, with the engine OFF.
- Measure the voltage of the throttle actuator control (TAC) motor control 1 and TAC motor control 2 circuits of the throttle actuator control motor with a DMM connected to the engine control module (ECM) housing.
Is the voltage within the specified range for both circuits? | 2-4 V | Go to Step 8 | Go to Step 9 |
| 8 | - Turn OFF the ignition.
- With a Test Lamp connected to ground, prove the TAC motor control 1 and TAC motor control 2 circuit of the throttle body harness connector.
- Turn ON the ignition for about 5 seconds and then turn OFF the ignition while you observe the test lamp. Repeat this procedure, as necessary.
Does the test lamp turn ON and then OFF each time the ignition is cycled? | - | Go to Step 12 | Go to Step 11 |
| 9 | Is the voltage less than the specified value? | 2 V | Go to Step 10 | Go to Step 14 |
| 10 | Test the TAC motor control circuit that measured below the specified value for an open or a short to ground. Did you find and correct the condition? | - | Go to Step 18 | Go to Step 13 |
| 11 | - Turn OFF the ignition.
- Disconnect the ECM.
- Test for continuity between the TAC motor control 1 and TAC motor control 2 circuit of the throttle body harness connector.
Is there continuity? | - | Go to Step 15 | Go to Step 13 |
| 12 | Test for shorted terminals and for poor connections at the throttle body connector. Did you find and correct the condition? | - | Go to Step 18 | Go to Step 16 |
| 13 | Test for shorted terminals and for poor connections at the ECM. Did you find and correct the condition? | - | Go to Step 18 | Go to Step 17 |
| 14 | Repair the appropriate TAC motor control circuit for a short to voltage. Did you complete the repair? | - | Go to Step 18 | - |
| 15 | Repair the short between the TAC motor control circuits 1 and 2. Did you complete the repair? | - | Go to Step 18 | - |
| 16 | Replace the throttle body assembly. Did you complete the replacement? | - | Go to Step 18 | - |
| 17 | Replace the ECM. Did you complete the replacement? | - | Go to Step 18 | - |
| 18 | - 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 19 |
| 19 | 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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