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Diagnosis and Testing|Removal and Installation > < Engine Emission Control

Focus 2004.75 (07.2004-)

Engine Emission Control - 1.8L Duratorq-TDCi (Lynx) Diesel - Engine Emission Control— Focus 2004.75 (07/2004-)
Diagnosis and Testing

General Equipment
Worldwide Diagnostic System (WDS) (418-F224)

Principles of Operation

Exhaust Gas Recirculation (EGR) system

To maintain the standards of low exhaust emission levels required of today's engines, the EGR system on this engine is fully electronically controlled.

The EGR valve is a proportional electric motor controlled directly by a duty-cycle signal from the powertrain control module (PCM). Integrated into the EGR valve is a valve position sensor. The signal from the EGR valve position sensor allows for the precise control of the timing and the quantity of exhaust gas to be recirculated. If the EGR valve becomes inoperative or fails to close completely, the PCM will raise a diagnostic trouble code (DTC) and the instrument cluster malfunction indicator lamp (MIL) will be illuminated.

If a new EGR valve is installed. The base setting (closed position) value must be configured to the PCM. This is initiated using WDS. If the base setting is not configured to the PCM, the setting from the previous EGR valve will be used and the control function of the EGR system will be incorrect.

The EGR system is fitted with an EGR cooler. The EGR cooler reduces the temperature of the exhaust gasses being returned to the intake system. By reducing the EGR temperature, the intake air charge density is not adversely affected, so maintaining the optimum fueling characteristics.

Positive Crankcase Ventilation (PCV) system

 
Item
Part Number
Description
1
-
PCV valve cover
2
-
PCV valve diaphragm
3
-
PCV valve bush
4
-
PCV valve spring
5
-
Valve cover

The PCV system is made up of an oil separator chamber connected to the crankcase and valve cover by hoses.

The crankcase pressure is controlled by a diaphragm operated PCV valve built into the valve cover. As the pressure in the oil separator reduces, the diaphragm valve closes against the force of the PCV valve spring, so closing the PCV valve. As the crankcase pressure rises, the PCV valve is pushed open assisted by the PCV valve spring. This allows the positive crankcase gasses to be scavenged by the air intake system.

Inspection and Verification

  1. Verify the customer concern.
  1. Visually inspect for obvious signs of mechanical or electrical damage.

Visual Inspection Chart

Mechanical Electrical
  • Exhaust gas recirculation (EGR) valve
  • EGR cooler
  • Gasket
  • PCV hoses
  • PCV oil separator
  • Electrical connector
  • Wiring harness
  1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step
  1. If the cause is not visually evident, verify the symptom and refer to the diagnostic trouble code (DTC) chart.

Diagnostic Trouble Code (DTC) Index Chart

DTC Description/Condition Possible Source Action
P1402 EGR metering orifice restricted EGR valve stuck closed or leaking GO to Pinpoint Test A.
  1. If no DTC's are retrieved, verify the symptom and refer to the symptom chart.

Symptom Chart

Symptom Chart

Symptom Possible Sources Action
Excessive exhaust black smoke
*
EGR valve.
*
GO to Pinpoint Test A.
Excessive crankcase pressure
*
Blocked or damaged PCV hose(s).
*
Blocked PCV oil separator.
*
GO to Pinpoint Test B.
*
Worn or damaged engine components.
*
REFER to Engine.

Pinpoint Tests

PINPOINT TEST A : EXCESSIVE EXHAUST BLACK SMOKE
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
A1: CHECK THE EGR VALVE
1
Using WDS, CHECK for DTC P1402.

Is DTC P1402 retrieved?
Yes
INSTALL a new EGR valve.
REFER to: Exhaust Gas Recirculation (EGR) Valve (303-08E Engine Emission Control - 1.8L Duratorq-TDCi (Lynx) Diesel, Removal and Installation).
TEST the system for normal operation.
No
Continue the diagnostic using WDS.

PINPOINT TEST B : EXCESSIVE CRANKCASE PRESSURE
TEST CONDITIONS DETAILS/RESULTS/ACTIONS
B1: CHECK THE PCV HOSES FOR BLOCKAGE

1
Remove the PCV hoses.
2
Inspect the PCV hoses for blockage.

Are the PCV hoses free from blockage?
Yes
GO to B2.
No
CLEAN or INSTALL new PCV hoses as necessary. TEST the system for normal operation.
B2: CHECK THE PCV VALVE FOR DAMAGE

1
Inspect the PCV valve for damage or blockage.

Is the PCV valve spring undamaged and the PCV valve free from blockage?
Yes
TEST the system for normal operation. If the concern persists, REFER to Engine.
No
CLEAN the PCV oil separator and PCV valve assembly or INSTALL a new valve cover as necessary TEST the system for normal operation.

Diagnosis and Testing|Removal and Installation > < Engine Emission Control