P026D

DTC P026C or P026D

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 P026C
- Injection Quantity Too Low

DTC P026D
- Injection Quantity Too High

Circuit/System Description

In order to compensate for variations in the fuel system, the fuel mass observer function adapts a correction quantity using the difference between the measured and modeled oxygen content of the exhaust gas coming from NOx Sensor 1. A DTC will set when the correction quantity reaches the emission OBD limit. If the correction quantity is below the calibrated threshold for a specified time, the corresponding "Injection Quantity Too Low" fault will be set. If the correction quantity is above the calibrated threshold for a specified time, the corresponding "Injection Quantity Too High" fault will be set.

Conditions for Running the DTC

* Ambient air temperature is above -7°C (19°F).

* NOx signal is active.

* Engine coolant temperature is greater than 65°C (149°F).

* BARO is greater than 75 kPa.

* Engine speed is between 448 and 1040 RPM.

* Diesel Particulate Filter (DPF) Regeneration not active.

* Vehicle speed less than 2 mph.

* PTO not engaged.

* Gear position is in drive or reverse.

* No other DTCs are present.

* The DTC runs once per trip.

Conditions for Setting the DTC

A fault is detected when the corrected quantity exceeds the allowed limit for greater than 12 seconds.

Action Taken When the DTC Sets

DTCs P026C and P026D are Type B DTCs.

Conditions for Clearing the DTC

DTCs P026C and P026D are Type B DTCs.

Diagnostic Aids

* This Diagnostic parameter is stored in the ECM over a period of time. Time to set this DTC may take several drive cycles.

* Contaminated or improper fuel quality may cause this DTC to set.

* Worn base engine components or differences in cylinder compression may cause this DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

Description and Operation

Fuel System Description Fuel System Description

Exhaust Aftertreatment System Description Exhaust Aftertreatment System Description

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 Control Module References for scan tool information.

Circuit/System Verification

1. Ignition ON

2. Observe the DTC information with a scan tool. Verify no other DTCs are set.

• If other DTCs are set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

• If no other DTCs.

3. Verify the scan tool MAF Sensor parameter is between 10 and 40 g/s.

• If less than 10 g/s
Check for intake system leaks. Refer to Charge Air Cooler Diagnosis (Full System Air Leak Test) Charge Air Cooler Diagnosis (Full System Air Leak Test)Charge Air Cooler Diagnosis (Induction System Smoke Test) Charge Air Cooler Diagnosis (Induction System Smoke Test).

If no intake system leaks are found, perform a Diesel Particulate Filter (DPF) Service Regeneration Diesel Particulate Filter (DPF) Service Regeneration.

• If greater than 40 g/s
Check for intake system leaks. Refer to Charge Air Cooler Diagnosis (Full System Air Leak Test) Charge Air Cooler Diagnosis (Full System Air Leak Test)Charge Air Cooler Diagnosis (Induction System Smoke Test) Charge Air Cooler Diagnosis (Induction System Smoke Test).

• If between 10 and 40 g/s

4. Verify there are no exhaust system leaks. Refer to Exhaust Leakage Testing and Inspection.

• If exhaust system leaks were found
Repair as necessary

• If no exhaust system leaks were found

Note: A/C must be in the off position

5. Engine idling at operating temperature and in drive.

6. Verify using the scan tool that the fuel injection quantity is between 9mm3 and 16mm3.

• If not between 9mm3 and 16mm3
Refer to Fuel Injector Balance Test with Tech 2 Fuel Injector Balance Test with Tech 2

• If between 9mm3 and 16mm3

7. Replace the B195 NOx sensor 1.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic repair.

* Nitrogen Oxide Sensor Replacement - Position 1 Nitrogen Oxide Sensor Replacement - Position 1

* Perform the scan tool NOx Sensor 1 Reset procedure after replacing NOx sensor 1.

* Fuel Injector Replacement (Right Side) Service and RepairFuel Injector Replacement (Left Side) Service and Repair

* Perform the Fuel Injector Flow Rate Programming Fuel Injector Flow Rate Programming and Fuel Injector Correction Reset Fuel Injector Correction Reset procedures after replacement of a fuel injector.