DTC P1388-P138A, P14A7-P14B4, P14D9, P14DA, P23AE, P23AF, P23B1-P23B5,
Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5507249 DTC P1388-P138A, P14A7-P14B4, P14D9, P14DA, P23AE, P23AF, P23B1-P23B5, P23B8, P23B9, P23C1, P2A02, P2C63-P2C65, or U05A8 Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC P1388 Nitrogen Oxides Sensor 3 Signal Circuit DTC P1389 Nitrogen Oxides Sensor 3 Signal Circuit Low DTC P138A Nitrogen Oxides Sensor 3 Signal Circuit High DTC P14A7 Oxygen Reference Voltage Circuit (Nitrogen Oxides Sensor 3) DTC P14A8 Oxygen Reference Voltage Circuit Low (Nitrogen Oxides Sensor 3) DTC P14A9 Oxygen Reference Voltage Circuit High (Nitrogen Oxides Sensor 3) DTC P14AA Oxygen Signal Circuit (Nitrogen Oxides Sensor 3) DTC P14AB Oxygen Signal Circuit Low (Nitrogen Oxides Sensor 3) DTC P14AC Oxygen Signal Circuit High (Nitrogen Oxides Sensor 3) DTC P14AD Oxygen Pump Current Control Circuit (Nitrogen Oxides Sensor 3) DTC P14AE Oxygen Pump Current Control Circuit Low (Nitrogen Oxides Sensor 3) DTC P14AF Oxygen Pump Current Control Circuit High (Nitrogen Oxides Sensor 3) DTC P14B0 Oxygen Low Reference Circuit (Nitrogen Oxides Sensor 3) DTC P14B1 Oxygen Low Reference Circuit Low (Nitrogen Oxides Sensor 3) DTC P14B2 Oxygen Low Reference Circuit High (Nitrogen Oxides Sensor 3) DTC P14B3 Nitrogen Oxides Sensor 3 Heater Ground Circuit DTC P14B4 Nitrogen Oxides Sensor 3 Heater Ground Circuit High DTC P14D9 Nitrogen Oxides Sensor 3 Offset Learning At Minimum Limit DTC P14DA Nitrogen Oxides Sensor 3 Current Performance DTC P23AE Nitrogen Oxides Sensor 3 Circuit Low DTC P23AF Nitrogen Oxides Sensor 3 Circuit High DTC P23B1 Nitrogen Oxides Sensor 3 Heater Control Circuit DTC P23B2 Nitrogen Oxides Sensor 3 Heater Control Circuit Low DTC P23B3 Nitrogen Oxides Sensor 3 Heater Control Circuit High DTC P23B4 Nitrogen Oxides Sensor 3 Heater Feedback Circuit DTC P23B5 Nitrogen Oxides Sensor 3 Heater Feedback Performance DTC P23B8 Nitrogen Oxides Sensor 3 Heater Feedback Circuit Low DTC P23B9 Nitrogen Oxides Sensor 3 Heater Feedback Circuit High DTC P23C1 Nitrogen Oxides Sensor 3 Performance - Sensing Element DTC P2A02 Heated Oxygen Sensor 3 Performance DTC P2C63 Heated Oxygen Sensor 3 Pump Current Trim Circuit Low DTC P2C64 Heated Oxygen Sensor 3 Pump Current Trim Circuit High DTC P2C65 Heated Oxygen Sensor 3 Performance During Deceleration Fuel Cut-Off DTC U05A8 Invalid Data Received From NOx Sensor 3 Circuit/System Description For an overview of the component/system, refer to: Exhaust Aftertreatment System Description
| Component | Description |
|---|---|
| B195 Nitrogen Oxides Sensor | NOx sensors work similar to wide-band O2 sensors. The sensors consist of two measuring cells. In the first cell, an electric pump current is used to separate out the oxygen in the exhaust. The NOx remains and is conveyed into the second chamber. Here a second pump current decomposes the NOx into nitrogen and oxygen. The oxygen concentration is measured and from there the NOx concentration can be calculated. The sensor delivers signals for wide-band lambda, digital lambda and NOx concentration. The sensor is attached to a control module that is calibrated to this particular sensor. The module communicates with the engine control module via serial data. |
| K20 Engine Control Module | The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly. |
Lean-burn engines operate with excess oxygen. This produces harmful nitrogen oxides (NOx) which are stored in the adsorber catalyst. The nitric oxide (NO) is first oxidized to nitrogen dioxide (NO2). To regenerate the catalyst when the storage capacity is reached, the engine control module cyclically uses a rich, reducing mixture so that the NO2 is converted to nitrogen (N2), water (H2O) and carbon dioxide (CO2). Two NOx sensors are mounted upstream and downstream of the selective catalytic reduction catalyst. The upstream sensor is used to determine how much reductant should be injected. The downstream sensor is used for adaptation and diagnostic of the system. Conditions for Running the DTC P1388, P1389, P138A, P14A7, P14A8, P14A9, P14AA, P14AB, P14AC, P14AD, P14AE, P14AF, P14B0, P14B1, P14B2, P14B3, P14B4, P23B1, P23B2, P23B3, P23B4, P23B8, P23B9 DTC P30B5, U02A1 = Not set Ignition and Start Switch Signal = Greater than 11 V Nitrogen Oxides Sensor 3 Heater Operation = Allowed Nitrogen Oxides Sensor 3 Supply Voltage Circuit = Greater than 9.9 V Frequency the DTC runs = Continuously — After the running conditions are met — For greater than 1.5 s P14D9 DTC P200C, U02A1 = Not set DTCs related to the following system/component = Not Set – B17 Barometric Pressure Sensor – B26 Crankshaft Position Sensor – B34 Engine Coolant Temperature Sensor – B65 Intake Manifold Pressure and Air Temperature Sensor – B75C Multifunction Intake Air Sensor – B115 Vehicle Speed Sensor – B131 Exhaust Temperature Sensor – B154 Diesel Particulate Filter Exhaust Differential Pressure Sensor – B345R Exhaust Pressure Differential Sensor - Exhaust Gas Recirculation – KR121B Reductant Control Module Relay 2 – M103 Turbocharger Vane Position Actuator – Q14 Exhaust Gas Recirculation Valve – Q17 Fuel Injector – Q18 Fuel Pressure Regulator – Q20 Intake Air Flow Valve No other DTCs related to the concerned component are set. Deceleration Fuel Cut-Off = Active Engine Speed 550 to 4,500 RPM Ignition and Start Switch Signal = Greater than 11 V Nitrogen Oxides Sensor 3 Heater Operation = Allowed Nitrogen Oxides Sensor 3 Supply Voltage Circuit = Greater than 9.9 V Particulate Filter Regeneration = Inactive — For greater than 60 s Frequency the DTC runs = Continuously — After the running conditions are met P14DA, P23AE, P23AF DTC P30B5, U02A1 = Not set Engine = Running Ignition and Start Switch Signal = Greater than 11 V Nitrogen Oxides Sensor 3 Heater Operation = Allowed Nitrogen Oxides Sensor 3 Supply Voltage Circuit = Greater than 9.9 V Frequency the DTC runs = Continuously — After the running conditions are met — For greater than 6 s P23B5 DTC U02A1 = Not set Ignition and Start Switch Signal = Greater than 11 V Nitrogen Oxides Sensor 3 Heater Operation = Allowed Nitrogen Oxides Sensor 3 Supply Voltage Circuit = Greater than 9.9 V Particulate Filter Regeneration = Inactive Frequency the DTC runs = Continuously — After the running conditions are met — For greater than 200 s P2A02 DTC B30B4, B30B5, U029D, U029E, U02A1 = Not set DTCs related to the following system/component = Not Set – B17 Barometric Pressure Sensor – B26 Crankshaft Position Sensor – B34 Engine Coolant Temperature Sensor – B65 Intake Manifold Pressure and Air Temperature Sensor – B75C Multifunction Intake Air Sensor – B131 Exhaust Temperature Sensor – B154 Diesel Particulate Filter Exhaust Differential Pressure Sensor – B195A Nitrogen Oxides Sensor 1 – B195B Nitrogen Oxides Sensor 2 – Q14 Exhaust Gas Recirculation Valve – Q17 Fuel Injector No other DTCs related to the concerned component are set. Engine Speed = 1,000 to 2,000 RPM Ignition and Start Switch Signal = Greater than 11 V Exhaust Gas Temperature Sensor 3 = −7 to 400°C (19 to 752°F) Nitrogen Oxides Sensor Heater Mode = Allowed Nitrogen Oxides Sensor 2 Heater Mode = Allowed Nitrogen Oxides Sensor 3 Heater Mode = Allowed Nitrogen Oxides Sensor Supply Voltage Circuit = Greater than 9.9 V Nitrogen Oxides Sensor 2 Supply Voltage Circuit = Greater than 9.9 V Nitrogen Oxides Sensor 3 Supply Voltage Circuit = Greater than 9.9 V Frequency the DTC runs = Continuously — After the running conditions are met P2C63, P2C64 DTC U02A1 = Not set Engine = Running Ignition and Start Switch Signal = Greater than 11 V No other DTCs related to the concerned component are set. Nitrogen Oxides Sensor 3 Heater Operation = Allowed Nitrogen Oxides Sensor 3 Supply Voltage Circuit = Greater than 9.9 V Frequency the DTC runs = Continuously — After the running conditions are met — For greater than 5 s P2C65 DTC U029D, U029E, U02A1 = Not set DTCs related to the following system/component = Not Set – B17 Barometric Pressure Sensor – B34 Engine Coolant Temperature Sensor – B65 Intake Manifold Pressure and Air Temperature Sensor – B75C Multifunction Intake Air Sensor – B131 Exhaust Temperature Sensor – B154 Diesel Particulate Filter Exhaust Differential Pressure Sensor – B170 Intake Manifold Tuning Valve Sensor – B195A Nitrogen Oxides Sensor 1 – B195B Nitrogen Oxides Sensor 2 – Q14 Exhaust Gas Recirculation Valve – Q17 Fuel Injector – Q18 Fuel Pressure Regulator – Q22 Intake Manifold Tuning Solenoid Valve No other DTCs related to the concerned component are set. Engine Speed 600 to 3,000 RPM Ignition and Start Switch Signal = Greater than 11 V Nitrogen Oxides Sensor Heater Mode = Allowed Nitrogen Oxides Sensor 2 Heater Mode = Allowed Nitrogen Oxides Sensor 3 Heater Mode = Allowed Nitrogen Oxides Sensor Supply Voltage Circuit = Greater than 9.9 V Nitrogen Oxides Sensor 2 Supply Voltage Circuit = Greater than 9.9 V Nitrogen Oxides Sensor 3 Supply Voltage Circuit = Greater than 9.9 V Frequency the DTC runs = Continuously — After the running conditions are met U05A8 Engine = Running Ignition and Start Switch Signal = Greater than 11 V No other DTCs related to the concerned component are set. Nitrogen Oxides Sensor 3 Heater Operation = Allowed Nitrogen Oxides Sensor 3 Supply Voltage Circuit = Greater than 9.9 V Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC Nitrogen Oxides Sensor 3 Circuit = Not within a calibrated range — For greater than 2 s Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type B DTC — Exceptions listed below P1388, P14A7, P14AA, P14AD, P14B0, P14B3, P23B1, P23B4, P23C1 = Type A DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type B DTC — Exceptions listed below P1388, P14A7, P14AA, P14AD, P14B0, P14B3, P23B1, P23B4, P23C1 = Type A DTC Reference Information Schematic Reference Engine Controls Schematics Connector End View Reference Master Electrical Component List 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 Circuit/System Verification
- Ignition » On / Vehicle » In Service Mode
- Verify there are no DTCs set related to the following component/system: – B17 Barometric Pressure Sensor – B26 Crankshaft Position Sensor – B34 Engine Coolant Temperature Sensor – B65 Intake Manifold Pressure and Air Temperature Sensor – B75C Multifunction Intake Air Sensor – B115 Vehicle Speed Sensor – B131 Exhaust Temperature Sensor – B154 Diesel Particulate Filter Exhaust Differential Pressure Sensor – B195A Nitrogen Oxides Sensor 1 – B195B Nitrogen Oxides Sensor 2 – B345R Exhaust Pressure Differential Sensor - Exhaust Gas Recirculation – KR121B Reductant Control Module Relay 2 – M103 Turbocharger Vane Position Actuator – Q14 Exhaust Gas Recirculation Valve – Q17 Fuel Injector – Q18 Fuel Pressure Regulator – Q20 Intake Air Flow Valve ⇒ If a related DTC is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If a related DTC is not set
- Verify the following conditions do not exist: Induction System — Leaking » Refer to: Charge Air Cooler Diagnosis Exhaust System / Turbocharger — Leaking » Refer to: Symptoms - Engine Exhaust ⇒ If a condition exists » Repair or replace as necessary ⇓ If no condition exists
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. Verify the DTC does not set. ⇒ If the DTC sets Replace the component: B195C Nitrogen Oxides Sensor 3 ⇓ If the DTC does not set
- All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Nitrogen Oxides Sensor Replacement - Position 3