P0473
P0473-EXHAUST PRESSURE SENSOR 1 HIGH
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Exhaust Gas Pressure Sensor is used to measure exhaust gas pressure in the exhaust manifold. The Powertrain Control Module (PCM) provides a 5-Volt supply to the Exhaust Gas Pressure Sensor on the sensor supply circuit. The PCM also provides a ground on the sensor return circuit. The Exhaust Gas Pressure Sensor provides a signal to the PCM on the Exhaust Gas Pressure Sensor Signal circuit. At key on, the readings for the exhaust gas pressure, intake Manifold pressure and ambient air pressure are compared. This fault code occurs if the exhaust gas pressure reading is different from the other two. During normal engine operation EGR position and Boost Pressure Sensor readings are used to calculate an estimated exhaust pressure. If the difference between the estimated and the value read from the Exhaust Gas Pressure Sensor is above a calibrated threshold for a calibrated period of time then an error is recorded. The key-on portion of the rationality will light the MIL immediately after the diagnostic runs and fails. The rationality portion has to fail in two consecutive drive cycles for the MIL to become illuminated. If this fault becomes active the PCM will light the MIL light immediately. During this time the PCM uses an estimated exhaust gas pressure. The PCM turns off the MIL when the diagnostic runs and passes in four consecutive drive cycles.
- When Monitored:
Ignition on.
- Set Condition:
The circuit voltage to the PCM is above 4.75 Volts for five seconds.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. ACTIVE DTC
NOTE: If any 5-Volt supply DTCs are present, repair those DTCs before proceeding.
1. Turn the ignition on.
2. With the scan tool, record all Freeze frame data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for 75 seconds.
5. Turn the ignition on.
6. With the scan tool, read DTCs.
Did the DTC reset?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test
2. CHECK THE (K355) EXHAUST PRESSURE SENSOR SIGNAL FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Exhaust Pressure Sensor harness connector.
3. Disconnect the PCM C1 harness connector.
NOTE: Check connectors - Clean/repair as necessary.
4. Remove the ASD/Main Relay.
5. Connect a jumper between cavity 30 and cavity 87 of the ASD/Main Relay connector.
6. Turn the ignition on.
7. Measure the voltage on the (K355) Exhaust Pressure Sensor Signal circuit at the Exhaust Pressure Sensor harness connector.
Is there any voltage present?
Yes
- Repair the (K355) Exhaust Pressure Sensor Signal circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Go To 3
3. CHECK THE (K916) SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Measure the resistance of the (K916) Sensor Ground circuit between the Exhaust Pressure Sensor harness connector and the PCM C1 harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 4
No
- Repair the (K916) Sensor Ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
4. CHECK THE EXHAUST PRESSURE SENSOR
1. Reconnect the PCM C1 harness connector.
2. Turn the ignition on.
3. While monitoring the scan tool, connect a jumper across the (K355) Exhaust Pressure Sensor Signal circuit and the (K916) Sensor Ground circuit at the Exhaust Pressure Sensor harness connector.
Did the scan tool display DTC P0472 active?
Yes
- Replace the Exhaust Pressure Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Replace the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.