Diagnostic Instructions

DTC Descriptors

DTC P2452 03: Diesel Particulate Filter (DPF) Differential Pressure Sensor Circuit Voltage Below Threshold

DTC P2452 07: Diesel Particulate Filter Differential (DPF) Pressure Sensor Circuit Voltage Above Threshold

Circuit/System Description

The diesel exhaust after-treatment system consists of an under hood pre-catalytic converter and an underbody catalytic converter. The underbody catalytic converter also consists of the main Diesel Oxidation Catalyst (DOC) and the coated Diesel Particulate Filter (DPF). One of the main purposes of the DPF is to collect particulates from the engine exhaust in order to minimize discharge of soot to the atmosphere. The soot particles accumulate in the channels of the DPF and are burned off at regular intervals through a process called regeneration. This prevents the DPF from clogging. The ECM commands the DPF regeneration after calculating various vehicle conditions such as DPF pressure difference, exhaust gas temperature, engine oil quality, engine speed, etc. Excessive accumulation of the soot in the DPF can cause a drop in the engine performance. During regeneration, additional fuel is injected via multiple post injections in order to increase the exhaust gas temperature. During this period, the DPF temperature is raised to approximately 600°C and the accumulated soot is oxidized or burned off into carbon dioxide (CO2).

Conditions for Running the DTC

Conditions for Setting the DTC

P2452 03

The ECM detects the DPF differential pressure sensor signal is less than 16 mV for greater than 2 seconds.

P2452 07

The ECM detects the DPF differential pressure sensor signal is greater than 4.9 volts for greater than 1 second.

Action Taken When the DTC Sets

DTC P2452 is a type A DTC.

Conditions for Clearing the DTC

DTC P2452 is a type A DTC.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Engine idling, observe the scan tool DPF differential pressure sensor parameter. The reading should be within 0-10 kPa (0-1.5 psi).
2. 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, and the MAIN fuse removed, disconnect the harness connector at the B154 DPF differential pressure sensor.
2. Test for less than 5 Ω between the low reference circuit terminal 2 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. Install the MAIN fuse. Ignition ON, test for 4.8-5.2 V between the 5-volt reference circuit terminal 1 and ground.

⇒	If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K20 ECM.

⇒	If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.

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

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

5. Install a 1 A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool DPF differential pressure sensor parameter is less than 0.5 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 test normal, replace the B154 DPF differential pressure sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.