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Home >> Chevy Truck >> 2011 >> Express 4500 V8-6.6L DSL Turbo >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P2455

P2455




DTC P2454 or P2455

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

DTC Descriptors
DTC P2454
- Diesel Particulate Filter Differential Pressure Sensor Circuit Low Voltage

DTC P2455
- Diesel Particulate Filter Differential Pressure Sensor Circuit High Voltage

Diagnostic Fault Information





Typical Scan Tool Data





Circuit/System Description

The exhaust pressure differential sensor measures the pressure difference across the inlet and outlet of the diesel particulate filter (DPF). The pressure difference across the DPF increases as captured particulates in the DPF increases. A diaphragm within the exhaust pressure differential sensor is displaced by the pressures change that occur from particulate matter loading. The engine control module (ECM) supplies a 5 V reference circuit and a ground on the low reference circuit. The exhaust pressure differential sensor provides a signal voltage to the ECM, relative to the back pressure as a function of exhaust flow, DPF temperature, and DPF soot loading. The ECM converts the signal voltage input to a pressure value.

Conditions for Running the DTC

P2454
* DTC P2455 is not set.
* The engine run time is greater than 10 s.
* The engine speed is greater than 600 RPM.
* The DTC runs continuously when the above conditions are met.

P2455
* DTC P2454 is not set.
* The engine run time is greater than 10 s.
* The engine speed is greater than 600 RPM.
* The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P2454

The ECM detects that the exhaust pressure differential sensor voltage is less than 0.83 V for 3 s.

P2455

The ECM detects that the exhaust pressure differential sensor voltage is greater than 4.6 V for 3 s.

Action Taken When the DTC Sets

DTCs P2454 and P2455 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P2454 and P2455 are Type B DTCs.

Diagnostic Aids

* Inspect the exhaust pressure differential sensor terminals for corrosion.
* Inspect the harness connector terminals for proper tension.

Reference Information
Schematic Reference

Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Exhaust Aftertreatment System Description (Emission Control Systems)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information
Special Tools

* J-23738-A Mityvac
* J-35555 Metal Mityvac

Circuit/System Verification

1. Ignition ON, observe the scan tool DTC information. DTC P0641 should not be set.

• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle) for further diagnosis.

2. Verify the integrity of entire DPF system by inspecting for the following conditions:

* Damaged components
* Loose or improper installation
* Incorrect differential pressure line routing
* Leaks or restrictions in the B154 exhaust pressure differential sensor lines or hoses. The pressure lines should have a continuous downward gradient, without sharp bends, or kinks from the pressure sensor to the exhaust filter assembly.

3. Ignition ON, observe the scan tool Particulate Filter Pressure Variance parameter. The value should be between -1.0 kPa to +0.3 kPa.
4. Engine running at a warm stabilized idle, observe the scan tool Particulate Filter Pressure Variance parameter. The value should be between 0-3 kPa.
5. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B154 exhaust pressure differential sensor.
2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohm between the low reference circuit terminal 3 and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.

3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.

• If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
• If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.

4. Verify the scan tool DPF Pressure sensor parameter is greater than 4.8 V.

• If less than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K20 ECM.

5. Install a jumper wire between the low reference circuit terminal 3 and signal circuit terminal 2. Verify the scan tool DPF Pressure sensor parameter is less than 0.20 V.

• If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

6. If all circuits and the B154 exhaust pressure differential sensor lines test normal, test the B154 exhaust pressure differential sensor.

Component Testing

Note: You must perform the Circuit/System Testing in order to verify the integrity of the B154 exhaust pressure differential sensor circuits before proceeding with Component Testing.

1. Ignition OFF, remove the B154 exhaust pressure differential sensor.
2. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 and the corresponding terminal of the B154 exhaust pressure differential sensor. Install a jumper wire between the low reference circuit terminal 3 of the B154 exhaust pressure differential sensor and ground.
3. Connect a DMM between terminal 2 of the B154 exhaust pressure differential sensor and ground.
4. Ignition ON, with the J-23738-A or J-35555 connected to the B154 exhaust pressure differential sensor rear pressure port, slowly apply vacuum while monitoring the voltage on the DMM. The voltage should vary/increase and transition smoothly without any spikes or dropouts.

• If the voltage is erratic, replace the B154 exhaust pressure differential sensor.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Exhaust Pressure Differential Sensor Pipe Replacement (Exhaust Pressure Differential Sensor Pipe Replacement)
* Exhaust Pressure Differential Sensor Replacement (Exhaust Pressure Differential Sensor Replacement)
* Perform the scan tool Diesel Particulate Filter (DPF) Regeneration Enable (Diesel Particulate Filter (DPF) Regeneration Enable) procedure if the scan tool DPF Soot Mass is less than 30 g. If the scan tool DPF Soot Mass is 30 g or greater, perform the Diesel Particulate Filter (DPF) Service Regeneration (Diesel Particulate Filter (DPF) Service Regeneration) procedure.
* Control Module References (Programming and Relearning)for ECM replacement, programming, and setup

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