Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1462

6E2–299

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0401 EGR Flow Insufficient

060R200050

Circuit Description

The powertrain control module (PCM) tests the exhaust
gas recirculation (EGR) system during deceleration by
momentarily commanding the EGR valve to open while
monitoring the manifold absolute pressure (MAP) sensor
signal.  When the EGR valve is opened, the PCM
monitors the change in MAP input signal.  The PCM
compares the MAP change to a RPM vs. BARO table.
When the PCM interprets the change in MAP to be out of
limits, the PCM will set DTC P0401.  The number of test
samples required to accomplish this may vary according
to the severity of the detected flow error.
Normally, the PCM will only allow one EGR flow test
sample to be taken during an ignition cycle.  To aid in
verifying a repair, the PCM allows twelve test samples
during the first ignition cycle following a Tech 2 “Clear Info”
or a battery disconnect.  Between nine and twelve
samples should be sufficient for the PCM to determine
adequate EGR flow and pass the EGR test.

Conditions for Setting the DTC

D

No TP sensor, vehicle speed sensor (VSS), MAP
sensor, IAT sensor, IAC, EGR Pintle Position sensor,
ECT sensor, misfire, or automatic transmission DTCs
set.

D

Engine coolant temperature is greater than 60

°

C

(140

°

F).

D

Ignition voltage between 11.5 and 16 volts.

D

Vehicle speed is greater than 24 km/h (15 mph).

D

A/C clutch status is unchanged.

D

TCC status is unchanged.

Start Test

D

TP angle is less than 0.8%.

D

EGR duty cycle is less than 1%.

D

MAP is steady, changing less than 2 kPa.

D

Engine speed is between 1100 RPM and 2000 RPM
(M/T).

D

MAP between 10 kPa and 40 kPa.

D

Engine speed is between 900 RPM and 1500 rpm
(A/T).
The test will be aborted if the vehicle speed changes
by more than 16 km/h (10 mph), engine speed
changes by more than 100 RPM or the EGR is
opened less than 95% of commanded position.

D

The PCM will only run the EGR test during a closed
throttle condition.

D

The PCM will only run the EGR test at vehicle speeds
above 24 km/h (15 mph).

D

Several deceleration cycles will be necessary to run a
sufficient number of EGR flow tests.

Action Taken When the DTC Sets

D

The PCM will ON the MIL after second trip with
detected fault.

6E2–300

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

D

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

Diagnostic Aids

Check for the following conditions:

D

Poor connection or damaged harness – Inspect the
wiring harness for damage.  If the harness appears to
be OK, observe the Actual EGR Position display on the
Tech 2 while moving connectors and wiring harnesses
related to the EGR valve.  A change in the display will
indicate the location of the fault.

D

Ensure EGR valve is correctly mounted.  See
On-Vehicle Service.

Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs.  This
may assist in diagnosing the condition.

NOTE: If the EGR valve shows signs of excessive heat,
check the exhaust system for blockage (possibly a
plugged catalytic converter) using the “Restricted
Exhaust System Check”.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart
3. A malfunctioning MAP sensor can set an EGR DTC.

The MAP sensor could send a constant signal which
is not low enough to set a low MAP DTC.  The
constant signal from the MAP sensor also may not
be high enough to set a high MAP DTC. This step
verifies that the MAP sensor is responding.

6E2–301

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0401 – EGR Flow Insufficient

 

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

Is DTC P1404 also set?

—

Go to 

DTC

1404

Go to 

Step 3

3

1. Start the engine.
2. Monitor the MAP signal with a Tech 2 while idling.
3. While idling, jab the accelerator pedal about halfway

down and immediately let the engine return to idle.

Did the MAP value on the Tech 2 show an immediate
large change?

—

Go to 

Step 5

Go to 

Step 4

4

Replace the MAP sensor.

Is the action complete?

—

Verify repair

—

5

1. Inspect the exhaust system for modification of

original installed parts or leaks.

2. If a problem was found, repair exhaust system as

necessary.

Was a condition present that required repair?

—

Go to 

Step 8

Go to 

Step 6

6

1. Remove the EGR valve.
2. Visually and physically inspect the pintle, valve

passages and the adapter for excessive deposits or
any kind of a restriction.

3. If a problem is found, clean or replace EGR system

components as necessary.

Was a condition present that required repair?

—

Go to 

Step 8

Go to 

Step 7

7

1. Remove the EGR inlet and outlet pipes from the

exhaust manifold and the intake manifold.

2. Inspect the manifold EGR ports and the EGR inlet

and outlet pipes for a blockage caused by excessive
deposits or other damage.

3. If a problem is found, correct the condition as

necessary.

Was a condition present that required repair?

—

Go to 

Step 8

Refer to

Diagnostic

Aids

8

1. Review and record the Tech 2 Failure Records data.
2. Clear DTC and monitor the Tech 2 System Info

Screen while operating the vehicle as specified in
“Diagnostic Aids”.

3. Using a Tech 2, monitor “DTC” info for DTC P0401

until the DTC P0401 test runs.

4. Note the test result.

Does the Tech 2 indicate DTC P0401 failed this
ignition?

—

—

Repair

complete

6E2–302

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0402 EGR Pintle Crank Error

060R200050

Circuit Description

The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to commands from the PCM, and to
detect a fault if pintle position is stuck open. If the PCM
detects a pintle position signal indicates more than 21.5%
and more than for 625 msec during cranking, the PCM will
set DTC P0402.

Conditions for Setting the DTC

D

Ignition voltage is between 11 and 16 volts.

D

At Engine revolution less than 600 RPM, EGR pintle
position indicates more than 21.0% and more than for
625 msecs.

Action Taken When the DTC Sets

D

The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

D

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in Failure
Records data.

Conditions for Clearing the MIL/DTC

D

The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

D

A history DTC P0402 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D

DTC P0402 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

Check for the following conditions:

D

Foreign material on EGR valve between pintle and
seat may cause EGR stuck open. Inspect foreign
material in EGR valve.

D

Excessive carbon deposit may cause unsmooth
operation of EGR valve shaft. Inspect for carbon
deposit and clean up inside of carbon deposit.

D

Poor connection or damaged harness–inspect the
wiring harness for damage If the harness appears to be
OK, observe the EGR actual position display on the
Tech 2 while moving connectors and wiring harnesses
related to EGR valve. A change in the display will
indicate the location of the fault.

NOTE: If the EGR valve shows signs of excessive heat,
check the exhaust system for blockage (possibly a
plugged catalytic converter) using the “Restricted
Exhaust System Check”.