P0471

P0471-EXHAUST PRESSURE SENSOR 1 PERFORMANCE





For a complete wiring diagram Consult Diagrams/Electrical

The Barometric/Atmospheric Pressure Sensor is an internal component of the ECM and cannot be replaced separately. The ECM compares the signal of the Atmospheric/Barometric Sensor to the signal of the Exhaust Pressure Sensor during low engine rpm (non-turbocharger boost conditions) to determine the plausibility of these sensors.

- When Monitored:
Engine speed is below 670 rpm. There are no other Exhaust Pressure Sensor DTC's. There are no Atmospheric/Barometric Pressure Sensor DTC's.

- Set Condition:
The difference between the Exhaust Pressure Sensor Signal and the Atmospheric/Barometric Pressure Sensor Signal is greater than 400 hpa (5.8 psi.) for at least 3.0 seconds.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. DTC IS ACTIVE
Ignition on, engine not running.
With the scan tool, Clear DTCs in the Engine Control Module (ECM).
Monitor the scan tool for at least two minutes.
Cycle the ignition key off and on several times, leaving the ignition on for at least 10 seconds at a time.
Start the engine.
Allow the engine to reach normal operating temperature.
With the scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go To 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Intermittent Condition

2. EXHAUST GAS PRESSURE SENSOR CIRCUIT SHORTED TO VOLTAGE




Turn the ignition off.
Disconnect the Exhaust Gas Pressure Sensor harness connector.
Disconnect the Engine Control Module (ECM) harness connector.
Remove the ASD Relay from the PDC.
Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay Connector.
Turn the ignition on.
Measure the voltage of the (F858) Exhaust Gas Pressure Sensor 5 Volt Supply circuit in the Exhaust Gas Pressure Sensor harness connector.
Measure the voltage of the (K35) Exhaust Gas Pressure Sensor Signal circuit in the Exhaust Gas Pressure Sensor harness connector.
Measure the voltage of the (K934) Exhaust Gas Pressure Sensor Ground circuit in the Exhaust Gas Pressure Sensor harness connector.
Is there voltage present on any of the circuits?

Yes

- Repair the circuit for a short to voltage.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go to 3

3. EXHAUST GAS PRESSURE SENSOR CIRCUIT OPEN OR HIGH RESISTANCE




Turn the ignition off.
Remove the jumper wire and install the ASD relay.
Disconnect the Engine Control Module (ECM) connector.
Measure the resistance of the (F858) Exhaust Gas Pressure Sensor 5 Volt Supply circuit between the Exhaust Gas Pressure Sensor connector and the Engine Control Module (ECM) harness connector.
Measure the resistance of the (K35) Exhaust Gas Pressure Sensor Signal circuit between the Exhaust Gas Pressure Sensor connector and the Engine Control Module (ECM) harness connector.
Measure the resistance of the (K934) Exhaust Gas Pressure Sensor Ground circuit between the Exhaust Gas Pressure Sensor connector and the Engine Control Module (ECM) harness connector.
Is the resistance below 10.0 ohms for each of the circuits?

Yes

- Go to 4

No

- Repair the circuit for an open circuit or high resistance.
- Perform the ECM Verification Test Ver. 1. Verification Tests

4. EXHAUST GAS PRESSURE SENSOR CIRCUIT SHORTED TO GROUND




Measure the resistance between ground and the (F858) Exhaust Gas Pressure Sensor 5 Volt Supply circuit in the Exhaust Gas Pressure Sensor harness connector.
Measure the resistance between ground and the (K35) Exhaust Gas Pressure Sensor Signal circuit in the Exhaust Gas Pressure Sensor harness connector.
Is the resistance between ground and each circuit above 1000 ohms?

Yes

- Go to 5

No

- Repair the circuit for a short to ground.
- Perform the ECM Verification Test Ver. 1. Verification Tests

5. EXHAUST GAS PRESSURE SENSOR
Connect the Engine Control Module (ECM) connector.
Connect a jumper wire between the (K934) Exhaust Gas Pressure Sensor Ground circuit and the (K35) Exhaust Gas Pressure Sensor Signal circuit in the Exhaust Gas Pressure Sensor connector.
Turn the ignition on.
With the scan tool, Clear DTCs.
With the scan tool, select View DTCs.

NOTE: The scan tool should display a Exhaust Gas Pressure Sensor low voltage or short to ground DTC with the jumper wire in place.

Turn the ignition off.
Remove the jumper wire.
Reconnect the jumper wire between the (F858) Exhaust Gas Pressure Sensor 5 Volt Supply circuit and the (K35) Exhaust Gas Pressure Sensor Signal circuit in the Exhaust Gas Pressure Sensor connector.
Turn the ignition on.
With the scan tool, Clear DTCs.
With the scan tool, select View DTCs.

NOTE: The scan tool should display a Exhaust Gas Pressure Sensor high voltage or open DTC with the Exhaust Gas Pressure Sensor connector disconnected.

Does the scan tool display the DTC(s) as described above?

Yes

- Replace the Exhaust Gas Pressure Sensor.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go to 6

6. ENGINE CONTROL MODULE (ECM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors the Exhaust Gas Pressure Sensor and the Engine Control Module (ECM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Check for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Replace the Engine Control Module (ECM).
- Perform the ECM Verification Test Ver. 1. Verification Tests