Content .. 441 442 443 444 ..

Nissan Frontier D22. Manual - part 443

DTC P0400 EGR FUNCTION

EC-875

[VG33E]

DTC P0400 EGR FUNCTION

PFP:14710

Description

UBS00DJY

SYSTEM DESCRIPTION

This system cuts and controls vacuum applied to the EGR valve to suit engine operating conditions. This cut-
and-control operation is accomplished through the ECM and the EGRC-solenoid valve. When the ECM
detects any of the following conditions, current does not flow through the solenoid valve. This causes the
intake manifold vacuum to be discharged into the atmosphere. The EGR valve remains closed.

●

Low engine coolant temperature

●

Engine starting

●

High-speed engine operation

●

Engine idling

●

Excessively high engine coolant temperature

●

Mass air flow sensor malfunction

COMPONENT DESCRIPTION
Exhaust Gas Recirculation (EGR) Valve

The EGR valve controls the amount of exhaust gas routed to the
intake manifold. Vacuum is applied to the EGR valve in response to
throttle valve opening and EGRC-BPT valve operation. The vacuum
controls the movement of a taper valve connected to the vacuum
diaphragm in the EGR valve.

Sensor

Input Signal to ECM

ECM function

Actuator

Camshaft position sensor

Engine speed

EGR control

EGRC-solenoid valve

Mass air flow sensor

Amount of intake air

Engine coolant temperature sensor

Engine coolant temperature

Ignition switch

Start signal

Throttle position sensor

Throttle position

SEF317U

SEF783K

EC-876

[VG33E]

DTC P0400 EGR FUNCTION

EGRC-Solenoid Valve

The EGRC-solenoid valve responds to signals from the ECM. When
the ECM sends an ON (ground) signal, the coil in the solenoid valve
is energized. The vacuum signal (from the intake manifold collector
to the EGR valve) passes through the solenoid valve. The signal
then reaches the EGR valve.
When the ECM sends an OFF signal, a plunger will then move to cut
the vacuum signal from the intake manifold to the ECR valve.

On Board Diagnosis Logic

UBS00DJZ

If the absence of EGR flow is detected by EGR temperature sensor
under the condition that calls for EGR, a low-flow malfunction is
diagnosed.

DTC Confirmation Procedure

UBS00DK0

CAUTION:

Always drive vehicle at a safe speed.
NOTE:

●

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait
at least 5 seconds before conducting the next test.

●

P0400 will not be displayed at “SELF-DIAG RESULTS” mode with CONSULT-II even though DTC work
support test result is “NG”.

WITH CONSULT-II

Turn ignition switch ON.

SEF318UA

SEF073P

DTC No.

Trouble diagnosis

name

DTC detecting condition

Possible Cause

P0400

EGRC-solenoid
valve circuit close

●

No EGR flow is detected under condi-
tions that call for EGR.

●

EGR valve stuck closed

●

EGRC-BPT valve

●

Vacuum hose

●

EGRC-solenoid valve

●

EGR passage

●

EGR temperature sensor

●

Exhaust gas leaks

DTC P0400 EGR FUNCTION

EC-877

[VG33E]

Check “COOLAN TEMP/S” in “DATA MONITOR” mode with
CONSULT-II.
Confirm COOLAN TEMP/S valve is within the range listed
below.

If the value is out of range, park the vehicle in a cool place and
allow the engine temperature to stabilize. Do not attempt to
lower the engine coolant temperature with a fan or means other
than ambient air. Doing so may produce an inaccurate diagnos-
tic result.

Start engine and let it idle monitoring “COOLAN TEMP/S” value.
When the “COOLAN TEMP/S” value reaches 70

°C (158°F), immediately go to the next step.

Select “EGR SYSTEM P0400” of “EGR SYSTEM” in “DTC WORK SUPPORT” mode with CONSULT-II.

Touch “START”.

Accelerate vehicle to a speed of 40 km/h (25 MPH) once and
then stop vehicle with engine running.
If “COMPLETED” appears on CONSULT-II screen, go to step 9.
If “COMPLETED” does not appear on CONSULT-II screen, go to
the following step.

Check the output voltage of “THRTL POS SEN” (at closed throt-
tle position) and note it.

When the following conditions are met, “TESTING” will be dis-
played on the CONSULT-II screen. Maintain the conditions until
“TESTING” changes to “COMPLETED”. (It will take approxi-
mately 60 seconds or more.)

If “TESTING” is not displayed after 5 minutes, retry from
step 2.

Make sure that “OK” is displayed after touching “SELF-DIAG
RESULTS”. If “NG” is displayed, refer to

EC-880, "Diagnostic

Procedure"

Overall Function Check

UBS00DK1

Use this procedure to check the overall EGR function. During this check, a 1st trip DTC might not be con-
firmed.

WITH GST

Start engine and warm it up to normal operating temperature.

COOLAN TEMP/S: Less than 40

°C (104°F)

SEF013Y

SEF732Y

ENG SPEED

1,600 - 2,400 rpm (A/T)
1,800 - 2,600 rpm (M/T)

B/FUEL SCHDL

6 - 9 msec

THRTL POS SEN

− (X + 0.82) V

X = Voltage value measured at step 7

Selector lever

Suitable position

SEF733Y

SEF235Y

EC-878

[VG33E]

DTC P0400 EGR FUNCTION

Check the EGR valve lifting when revving engine from 2,000 to 3,000 rpm quickly under no load using the
following methods.

EGR valve should lift up and down without sticking.
If NG, go to

EC-880, "Diagnostic Procedure"

Check voltage between ECM terminal 63 (EGR temperature
sensor signal) and ground at idle speed.
Less than 4.5V should exist.
If NG, go to next step.

Turn ignition switch OFF.

Disconnect EGR temperature sensor harness connector.

Check harness continuity between EGR temperature sensor
harness connector terminal 2 and ground.

Perform

EC-895, "Component Inspection"

SEF642Q

SEF182V

AEC660A

Continuity should exist.

SEF102S

Content .. 441 442 443 444 ..