Differential Pressure Sensors
The Differential Pressure Sensor (DPS) monitors the performance of the Diesel Particulate Filter (DPF). The sensor operates by measuring the exhaust gas pressure upstream and downstream of the vehicle’s DPF. By monitoring the pressure difference between these two points, the saturation level of the Particle Filter can be determined, and the vehicle’s ECU can interpret the data to determine when to inject Diesel Exhaust Fluid (DEF) for regeneration.
Common causes of Differential Pressure Sensor failure:
• Electronics damaged from intense engine heat
• Vibration damage from prolonged exposure in the engine compartment
Symptoms of failing Differential Pressure Sensor may include:
• Engine will not start or starts poorly
• Detonation or misfire
• Excessive fuel consumption
• Lack of engine power
• Check Engine Light on
The following OBD II error codes are the most commonly found with this product type. In an effort to reduce vehicle emissions, the Environmental Protection Agency (EPA), mandated that all vehicles manufactured after 1996 would be equipped with OBD II (On Board Diagnostics 2) technology. OBD II is now the standard in diagnosing vehicle emissions, which was implemented by all automotive manufacturers in 1996. The codes listed for this product type are common instances that may relate to your vehicle and should be used as a guide only. Walker Products will not be held responsible for any use of this information. It is highly suggested that you consult with a professionally trained mechanic prior to any automotive repair, and that you follow all vehicle manufacturer and EPA guidelines for removal, replacement, diagnostics, OBD II code clearing, ECU, and PCM relearn procedures.
o P0068 MAP/MAF – Throttle Position Correlation
o P006A MAP – Mass or Volume Air Flow Correlation
o P006B MAP – Exhaust Pressure Correlation
o P006C MAP – Turbocharger/Supercharger Inlet Pressure Correlation
o P00B8 MAP – Mass or Volume Air Flow Correlation
o P0069 Manifold Absolute Pressure – Barometric Pressure Correlation
o P0105 Manifold Absolute Pressure/Barometric Pressure Circuit
o P0106 Manifold Absolute Pressure/Barometric Pressure Circuit
o P0107 Manifold Absolute Pressure/Barometric Pressure Circuit Low
o P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High
o P0109 Manifold Absolute Pressure/Barometric Pressure Circuit Intermittent
o P023D Manifold Absolute Pressure – Turbocharger/Supercharger Boost
o P023E Manifold Absolute Pressure – Turbocharger/Supercharger Boost
o P2073 Manifold Absolute Pressure/Mass Air Flow – Throttle Position
o P2074 Manifold Absolute Pressure/Mass Air Flow – Throttle Position
o P2226 Barometric Pressure Sensor “A” Circuit
o P2227 Barometric Pressure Sensor “A” Circuit Range/Performance
o P2228 Barometric Pressure Sensor “A” Circuit Low
o P2229 Barometric Pressure Sensor “A” Circuit High
o P222A Barometric Pressure Sensor “B” Circuit
o P222B Barometric Pressure Sensor “B” Circuit Range/Performance
o P222C Barometric Pressure Sensor “B” Circuit Low
o P222D Barometric Pressure Sensor “B” Circuit High
o P222E Barometric Pressure Sensor “B” Circuit Intermittent/Erratic
o P222F Barometric Pressure Sensor “A”/”B” Correlation
o P2230 Barometric Pressure Sensor “A” Circuit Intermittent/Erratic
o P2262 Turbocharger/Supercharger Boost Pressure not Detected –
o P226B Turbocharger/Supercharger Boost Pressure Too High – Mechanical
When troubleshooting engine sensors, it is recommended to look for any signs of visible damage first. Check all connections, starting with the sensor electrical connector, and look for any damage such as cracking or melting. Any damaged wires will need to be replaced.
Next, inspect the hoses connected to the sensor. Again, look for any damage such as cracking or melting. If the hoses are damaged, they will need to be replaced and most likely re-routed, so they are not damaged the same way again. If the hoses look to be in good physical condition, check for any blockage or clogs. If clogged, the hoses will need to be cleared or replaced.
If everything passes physical inspection, you can test the DPF differential pressure sensor using a multimeter set to 20V and a pressure gauge.
- With the battery on and engine off, connect the multimeter ground to the negative battery terminal and run a quick plausibility by checking the voltage of the battery. It should be around 12.6 volts.
- Consult the manufacturer’s service manual to identify the signal, ground, and 5-volt reference and back-probe the wires.
- Turn the ignition switch on without starting the engine. The multimeter should (typically) display a voltage between 4.5 to 5 volts for the 5-volt reference, a steady 0 volts for the ground wire, and between 0.5 and 4.5 volts for the signal wire. Consult OEM factory service information for the exact specs on your vehicle.
- Start the engine with the signal wire back-probed.
- Rev the engine and notice if there is a change in voltage. If not, move on to test the connecting hoses with a pressure gauge.
- With the engine still running, remove the hoses from the sensor.
- Using a pressure gauge, measure the pressure of both hoses. For sufficient accuracy, use an exhaust back pressure gauge that measures 0-15 PSI.
- Check the signal voltage again. The voltage should read a number between the pressure values of the hoses. For example, if the rear hose reads half PSI and the front hose reads 1 PSI, the voltage of the signal wire should read somewhere in the middle around .8 volts.
If your voltage differs greatly or the pressure values do not match the voltage reading, the DPF differential pressure sensor is faulty and will need to be replaced.
The Differential Pressure Sensor is located by the Diesel Particulate Filter (DPF) with probes connected to the exhaust stream on both the upstream and downstream side of the DPF.
If your check engine light is turned on, here are the codes associated with a DPF Differential Pressure Sensor. Any part or component should not be replaced only with reference to a Diagnostic Trouble Code (DTC). The vehicle service manual should always be consulted for more information on possible causes of the fault, along with required testing.
- P2452: Diesel Particulate Filter Pressure Sensor ‘A’ Circuit
- P2453: Diesel Particulate Filter Pressure Sensor A Circuit Range/Performance
- P2454: Diesel Particulate Filter Pressure Sensor “A” Circuit Low
- P2455: Diesel Particulate Filter Pressure Sensor A Circuit High
Note: An exhaust leak can cause these codes to set.