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P140B




DTC P140B or P140C

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 P140B

-
Exhaust Gas Recirculation (EGR) Flow Insufficient

DTC P140C

-
Exhaust Gas Recirculation (EGR) Flow Excessive

Circuit/System Description

The exhaust gas recirculation (EGR) valve is controlled by the engine control module (ECM). The ECM controls the EGR valve by supplying a 12-volt pulse width modulated (PWM) signal to the EGR solenoid low control circuit and 12 volts to the high control circuit. The ECM monitors the difference between the desired Mass Air Flow (MAF) and the actual MAF over a calibrated sampling time. If the average difference between desired and actual MAF during the specified time period is less than or greater than a calibrated threshold level the response time of detected EGR flow is determined to be out of range.

Conditions for Running the DTC

* DTC P0045, P0047, P0048, P006E, P006F, P007C, P007D, P008F, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0128, P0200, P02E0, P02E7, P02E8, P02E9, P02EB, P0400, P0403, P0405, P0406, P0489, P0490, P122C, P122E, P122F, P140D, P140E, P140F, P1407, P1411, P1412, P1413, P1414, P168C, P168D, P16A0, P16A1, P16A2, P2228, P2229, P2263, P2453, P245A, P245C, P245D, P2493, P2494, P2495, P2564, P2565, P2598, or P2599, is not set.

* The engine speed is between 1,300-2,000 RPM.

* The calculated fuel rate is between 28-55 mm 3

* The ambient air temperature is greater than -7°C (19.4°F).

* The engine coolant temperature is greater than 70°C (158°F)

* The Barometric Pressure is greater than 74.8 kPa (10.9 psi).

* The MAF rate is not in a steady state condition.

* The EGR valve is in closed loop and active.

* The DTCs run continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the average integrated difference between the actual mass air flow and the desired mass air flow is not within a minimum or maximum calibrated range over a 15 s time period.

Action Taken When the DTC Sets

DTC P140B and P140C are Type B DTCs.

Conditions for Clearing the DTC

DTC P140B and P140C are Type B DTCs.

Diagnostic Aids

Inspect for the following conditions that may cause this DTC to set:

* Contamination on the MAF sensor element

* Restriction before or after the MAF sensor

* Skewed MAF sensor

* Aftermarket air filter

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)

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

Note:
Occasionally, when using an EGR device control, Engine Reduced Power and Clean Exhaust Filter messages may occur after a short delay when commanding large EGR positions. The messages are a result of ECM protecting hardware during device control mode. No DTCs will be stored and the Diesel Particulate Filter does not need to be service cleaned. Exiting device control will restore normal function.

1. Ignition ON, observe the scan tool Desired EGR Position and the EGR Position Sensor parameters. Command the EGR valve between 0-40 % and back down to 0 % within 20 s with a scan tool. The parameters should respond quickly and remain within 3 % throughout the commanded range.

2. Engine running command the EGR Valve to 40 % with a scan tool, then increase the engine speed to 2,500 RPM. The engine should run rough.

3. Operate the vehicle within the Conditions for Running the DTC to verify that 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

Note:

* Perform the Circuit System Verification before proceeding with Circuit/System Testing.

* Always replace the EGR valve or EGR cooler gaskets when removal or replacement of the components are necessary.

* Recording of Mass Air Flow parameter g/s are valid only if the Reduced Engine Power message is not present.

1. Engine running, perform the following:

1. Maintain engine speed at idle.

2. With a scan tool, command the EGR solenoid to 0 % and record the MAF Sensor g/s parameter.

3. Command the EGR solenoid to 40 % with a scan tool while observing the EGR Position Sensor and the MAF Sensor g/s parameters. Record the MAF Sensor parameter. The difference between the MAF Sensor parameter at 0 % EGR solenoid position and 40 % EGR solenoid position should be greater than 15 g/s.

• If the MAF Sensor parameter is not within the specified range, inspect the EGR cooler and the EGR valve passages for a restriction. If a condition is found, repair or replace the affected component as necessary.

2. Ignition OFF, inspect for the following:

* The exhaust system for leaks, restrictions, or for modification of the Original Equipment Manufacturer (OEM) part

* A restriction in the air cleaner and the air intake ducts

* A restriction in the turbocharger charge air cooler system

* A restriction in the intake manifold

• If a condition is found, repair or replace the affected component as necessary.

3. Test the air induction system for air leaks between the MAF sensor and the turbocharger. Perform the Induction System Smoke Test. 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).

4. Test the charge air cooler system for leaks. Perform the Full System Air Leak Test. 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).

5. If the exhaust, air induction, charge air cooler and mass air flow systems test normal, Test or replace the Q14 EGR Valve.

Component Testing

Note:
Perform the Circuit/System Testing before proceeding with the Component Testing.

1. Ignition OFF, remove the Q14 EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement Exhaust Gas Recirculation Valve Replacement.

2. Inspect the Q14 EGR valve for the following conditions:

* A sticking, binding, or frozen EGR valve

* A leak or restriction in the EGR valve and EGR ports and passages

* Any coking, soot build up, debris or damage that can cause the EGR valve to stick partially open or closed

• If a condition is found, replace the Q14 EGR Valve.

Repair Instructions

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

* Exhaust Gas Recirculation Valve Replacement Exhaust Gas Recirculation Valve Replacement

* Control Module References Control Module References for ECM replacement, programming, and setup

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