For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC P2454 00: Diesel Particulate Filter (DPF) Differential Pressure Sensor Circuit Low Voltage
DTC P2455 00: Diesel Particulate Filter (DPF) Differential Pressure Sensor Circuit High Voltage
DTC P2455 01: Diesel Particulate Filter (DPF) Differential Pressure Sensor Circuit Short to Battery
DTC P2455 11: Diesel Particulate Filter (DPF) Differential Pressure Sensor Circuit High Input

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
5-Volt Reference | P0641 | P2454 00 | P0641 | P2453
Signal | P2454 00 | P2455 01 | P2455 01 | P2453
Low Reference | -- | P2455 01 | -- | P2453

### 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 (1112°F)and the accumulated soot is oxidized or burned off into carbon dioxide (CO2).

### Conditions for Running the DTC

• | The ignition is ON, or the engine is running.

• | The DTCs run continuously when the above condition is met.

### Conditions for Setting the DTC

#### P2454

The ECM detects an open circuit or a short to ground greater than 2 s.

#### P2455

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

### Action Taken When the DTC Sets

DTCs P2454, P2455 00 and P2455 11 are Type C DTCs.

DTC P2455 01 is a Type A DTC.

### Conditions for Clearing the DTC

DTCs P2454, P2455 00 and P2455 11 are Type C DTCs.

DTC P2455 01 is a Type A DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Exhaust Particulate Filter System Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### 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 diesel particulate filter data 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, disconnect the harness connector at the B154 Diesel Particulate Filter 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 Engine Control Module (ECM).

3. 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 Engine Control Module (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 Engine Control Module (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 Engine Control Module (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 Engine Control Module (ECM).

6. If all circuits test normal, replace the B154 Diesel Particulate Filter Pressure Sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Exhaust Pressure Sensor Replacement

• | Control Module References for ECM replacement, programming and setup.