Section 4.9
New for 2002
EGR Feature Operations:
Section 4.9.1
Sensor Failures
The system response to specific sensor failures, as required for proper EGR operation, are listed below:
Section 4.9.1.1
Barometric Pressure Sensor
Failure Modes: PID 108, FMI 3 – Voltage High and FMI 4 – Voltage Low.
Response: When either of the two failure modes is detected, the CEL will be illuminated and an approximate value of barometric pressure shall be used. To improve the accuracy of the approximation, when the engine returns to idle with boost mode active and a failed barometric sensor, the VNT vanes will be forced open for a period of time as determined by the calibration. After the delay period, normal boost mode operation will resume. The vane forcing will only run one time per boost mode event.
Section 4.9.1.2
Turbo Boost Pressure Sensor
Failure Modes: PID 102, FMI 3 – Voltage High and FMI 4 – Voltage Low.
Response: When either of the two failure modes is detected the CEL will be illuminated and the system will be forced into open loop boost mode. The commanded VNT vane position will be determined by a calibration value.
Section 4.9.1.3
Intake Manifold Pressure Sensor
Failure Modes: PID 106, FMI 3 – Voltage High and FMI 4 – Voltage Low.
Response: The CEL will be illuminated and the calibration default value will be used.
Section 4.9.1.4
Turbo Compressor Outlet Temperature Sensor
Failure Modes: PID 404, FMI 3 – Voltage High and FMI 4 – Voltage Low.
Response: When either of the two failure modes is detected, the CEL will be illuminated and the system will calculate a torque limit from the ECM calibration.
Section 4.9.1.5
EGR Delta-Pressure Sensor
Failure Modes: PID 411, FMI 3 – Voltage High and FMI 4 – Voltage Low.
Response: When either of the two failure modes is detected, the CEL will be illuminated and the system will be forced into boost mode. (EGR is disabled).
Section 4.9.1.6
EGR Temperature Sensor
Failure Modes: PID 412, FMI 3 – Voltage High and FMI 4 –Voltage Low.
Response: The CEL will be illuminated and the calibration default value will be used.
Section 4.9.1.7
Turbo Compressor Inlet Temperature Sensor
Failure Modes : PID 351, FMI 3 – Voltage High and FMI 4 – Voltage Low.
Response: When either of the two failure modes is detected the CEL will be illuminated and substitute values will be used.
Section 4.9.1.8
Relative Humidity Sensor
Failure Modes: PID 354, FMI 3 – Voltage High and FMI 4 – Voltage Low.
Response: The CEL will be illuminated and the calibration default value will be used.
Section 4.9.1.9
Coolant Temperature Sensor
Failure Modes: PID 110, FMI 3 – Voltage High and FMI 4 – Voltage Low.
Response: The CEL will be illuminated and the calibration default value will be used.
Section 4.9.1.10
Turbo Speed Sensor
Failure Modes: PID 103, FMI 8 – Abnormal Period.
Response: When this failure mode is detected, the CEL will be illuminated and the system will be forced into boost mode. The VNT vane position will be restricted so it will not be allowed to close beyond a certain position; i.e. the VPOD will only be able to adjust the vanes to a more open position.
Section 4.9.1.11
Ambient Air Temperature Sensor
Failure Modes: PID 171, FMI 3 – Voltage High and FMI 4 – Voltage Low.
Response: When either of the two failure modes is detected, the CEL will be illuminated. Ambient air temperature will be estimated based on the RH/TCI sensor.
Section 4.9.2
Mechanical Failures
The system response to detectable mechanical failures as required for this feature, are listed below:
Section 4.9.2.1
EGR Valve
- SID 146 FMI 7 – EGR Valve not responding – EGR
- SID 146 FMI 2 – EGR Leak – Boost Power
- SID 146 FMI 12 – EGR Leak – Boost Jake
146/7 – Occurs if actual EGR rate during EGR mode operation is less than it should be. This fault will lock boost mode operation and illuminate the CEL for the remainder of the ignition cycle.
146/2 – Occurs if actual EGR rate during Power Boost mode operation is greater than a calibrated value. This fault will illuminate the CEL for the duration of the fault being active.
146/12 – Occurs if actual EGR rate during Jake Boost mode operation is greater than a calibrated value. This fault will illuminate the CEL for the duration of the fault being active.
Section 4.9.3
VNT Vanes
- SID 147 FMI 7 – VNT Vanes not responding – EGR
- SID 147 FMI 2 – VNT Vanes not responding – Boost Power
- SID 147 FMI 12 – VNT Vanes not responding – Jake Power
- SID 147 FMI 14 – EGR Flow too low
147/7 – Occurs if error in actual EGR rate vs desired EGR rate (Actual - Desired) during EGR mode operation. This FMI signifies excessive EGR flow. This fault will lock boost mode operation and illuminate the CEL for the remainder of the ignition cycle if the actual is greater than the desired.
147/2 – Occurs if error in actual boost vs desired boost during Power Boost mode operation. This fault will illuminate the CEL for the duration of the fault being active.
147/12 – Occurs if error in actual boost vs desired boost during Jake Boost mode operation. This fault will illuminate the CEL for the duration of the fault being active.
147/14 – Occurs if error in actual EGR rate vs desired EGR rate (Desired - Actual) during EGR mode operation. This FMI signifies low EGR flow. This fault will illuminate the CEL for the duration of the fault being active.
| DDEC III/IV Single ECM Troubleshooting Guide - 6SE497 |
| Generated on 10-13-2008 |