P0472

P0472- EXHAUST PRESSURE SENSOR 1 LOW





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:

Ignition on, engine not running.

- Set Condition:

The circuit voltage to the ECM falls below 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. P0472 ACTIVE

Is DTC P0472 active?

Yes

- Go To 3

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

3. INTERMITTENT CONDITION





Turn the ignition off.

Disconnect the Exhaust pressure sensor 1/1 harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Turn the ignition on.

Measure the voltage from the Exhaust pressure sensor 1/1 (F855) 5-volt supply circuit to the Exhaust pressure sensor 1/1 (K916) sensor return circuit at the sensor harness connector.

Is the voltage between 4.5 and 5.5 volts?

Yes

- Go To 4

No

- Go To 6

4. EXHAUST PRESSURE SENSOR





While monitoring scan tool, use a jumper wire to connect the (F855) 5-volt supply circuit with the (K355) signal circuit at the sensor harness connector.

Does the scan tool show a P0473 DTC?

Yes

- Replace the Exhaust pressure sensor
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5

5. EXHAUST PRESSURE SENSOR (K355) SIGNAL CIRCUIT SHORTED TO THE (K916) SENSOR GROUND CIRCUIT





Turn the ignition off.

Disconnect the ECM harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between the (K355) signal circuit and (K916) sensor ground circuit in the Exhaust pressure sensor harness connector.

Is the resistance greater than 100 k Ohms?

Yes

- Go To 6

No

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

6. EXHAUST PRESSURE SENSOR (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO THE (K916) SENSOR GROUND





Turn the ignition off.

Measure the resistance between the (F855) 5-volt supply circuit and (K916) sensor ground circuit in the Exhaust pressure sensor harness connector.

Is the resistance greater than 100 k Ohms?

Yes

- Go To 7

No

- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

7. (K355) SIGNAL CIRCUIT OPEN





Measure the resistance between the (K355) signal circuit in the Exhaust Pressure sensor harness connector and the (K355) signal circuit in the ECM harness connector.

Is the resistance less than 10 ohms?

Yes

- Go To 8

No

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

8. (F855) 5-VOLT SUPPLY CIRCUIT OPEN





Measure the resistance between the (F855) 5-volt supply circuit in the Exhaust Pressure sensor harness connector with the (F855) 5-volt supply circuit in the ECM harness connector.

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. (K355) SIGNAL CIRCUIT SHORTED TO GROUND





Measure the resistance between the (K355) signal circuit in the Exhaust pressure sensor connector and battery negative.

Is the resistance greater than 100 k Ohms?

Yes

- Go To 10

No

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

10. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND





Measure the resistance between the (F855) 5-volt supply circuit in the Exhaust pressure sensor connector and battery negative.

Is the resistance greater than 100 k Ohms?

Yes

- Go To 11

No

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

11. ECM





While monitoring scan tool, use a jumper wire to connect the (F855) 5-volt supply circuit with the (K355) signal circuit at the sensor harness connector.

Does the scan tool show a P0473 DTC?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

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