P0473

P0473- EXHAUST PRESSURE SENSOR 1 HIGH





For complete wiring diagrams refer to Diagrams/Electrical.


Theory of Operation

The exhaust gas pressure sensor is used to measure exhaust gas pressure in the exhaust manifold. This information is used by the ECM to control emissions and EGR valve operation. The Electronic Control Module (ECM) provides a 5-volt supply to the exhaust gas pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The exhaust gas pressure sensor provides a signal to the ECM on the exhaust gas pressure sensor signal circuit. This sensor signal voltage changes based on the pressure in the exhaust manifold If this fault becomes active the ECM will light the MIL light immediately. During this time the ECM uses an estimated exhaust gas pressure. An engine power derate may be experienced. The ECM turns off the MIL when the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:

Key on

- Set Condition:

The circuit voltage to the ECM is above a calibrated threshold for a certain period of time







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. OTHER DTC'S

Ignition on, engine not running.

With the scan tool, read DTC's.

Are there any 5-volt supply DTC's ?

Yes

- Repair other DTC's first.

No

- Go To 2

2. P0473 ACTIVE

Is DTC P0473 active?

Yes

- Go To 3

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

3. (F855) 5-VOLT SUPPLY





Turn the ignition off.

Disconnect the Exhaust pressure sensor 1/1 harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Measure the voltage between the (F855) 5-volt supply circuit and (K916) return circuit of the exhaust pressure sensor harness connector.

Is the voltage between 4.5 and 5.5 volts?

Yes

- Go To 4

No

- Go To 5

4. EXHAUST PRESSURE SENSOR





While monitoring the scan tool, use a jumper wire to connect the (K916) return circuit to the (K355) signal circuit at the Exhaust Pressure sensor harness connector.

Does the scan tool show a P0472-Exhaust Pressure sensor low DTC?

Yes

- Replace the Exhaust Pressure Sensor.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5

5. (K355) SIGNAL WIRE SHORTED VOLTAGE





Turn the ignition off.

Disconnect the ECM harness connectors.


NOTE: Check connectors - Clean/repair as necessary.

Measure the voltage between the (K355) signal circuit of the Exhaust Pressure sensor connector and battery negative.

Is the voltage less than 1 volt?

Yes

- Go To 6

No

- Repair or replace the shorted wiring harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

6. (F855) 5 VOLT SUPPLY SHORTED TO HIGH VOLTAGE





Measure the voltage between the (F855) 5 volt supply circuit of the sensor connector and battery negative.

Is the voltage less than 1 volt?

Yes

- Go To 7

No

- Repair or replace the shorted wiring harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

7. (K355) SIGNAL CIRCUIT TO (F855) 5-VOLT SUPPLY





Measure the resistance between the (K355) signal circuit and the (F855) 5-volt supply circuit of the Exhaust Pressure sensor harness connector.

Is the resistance less than 10 ohms?

Yes

- Go To 8

No

- Repair or replace the shorted wiring harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

8. (K916) RETURN CIRCUIT OPEN





Measure the resistance between the (K916) return circuit in the Exhaust Pressure sensor harness connector with the (K916) return circuit in the ECM harness connector.

Is the resistance less than 10 ohms?

Is the resistance less than 10 ohms?

Yes

- Go To 9

No

- Repair or replace the open wiring harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

9. ECM





Reconnect the ECM harness connectors.

Ignition on, engine not running.

While monitoring scan tool, use a jumper wire to connect the (K916) return circuit with the (K355) signal circuit at the Exhaust Pressure sensor harness connector.

Does the scan tool show a P0472 Exhaust Pressure sensor low DTC?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Replace the ECM.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test